Month: February 2025

How Long Does It Take for Pancreatic Enzyme Replacement Therapy (PERT) to Start Working for People With Exocrine Pancreatic Insufficiency (EPI / PEI)?

by Dana Lewis

How long does it take for pancreatic enzyme replacement therapy to start working? A blog from Dana M. Lewis on DIYPS.orgIf you have been prescribed pancreatic enzyme replacement therapy (PERT), aka enzymes for exocrine pancreatic insufficiency (EPI or PEI), you may be wondering how long it will take before you start to feel better or it starts to work. This is a common question, and the answer depends on several factors, including the dosage, meal composition, and how well your body uses the enzymes. Some improvements can be seen within a single meal, while other benefits take longer to manifest. It also depends on whether you have EPI, or if you have EPI in concert with other types of gastrointestinal conditions, because some of your symptoms may be coming from other conditions.

Immediate Effects of PERT

PERT should start working with your very first meal, if your dose is in the ballpark of being ideal for you and your food intake. The enzymes help break down fats, proteins, and carbohydrates so your body can absorb nutrients more effectively. If you are taking somewhere in the ballpark of the right dose, you may notice immediate improvements in digestion, such as:

  • Less bloating or cramping after eating
  • Reduced gas
  • A decrease in diarrhea or greasy, foul-smelling stools

These improvements should occur on a per-meal basis. If you take PERT with one meal but not another, you may notice a stark difference in symptoms after each of those meals. This is a good indicator that the enzymes are working when you do take them.

Why Some People Don’t See Immediate Improvement With PERT

While PERT can provide relief after a meal or noticeable effects within a day or so, many people do not take a sufficient dose initially. Under-dosing is common, which means you may still experience symptoms as you fine-tune your enzyme intake.

Here are some reasons why you might not see immediate results:

  • Not taking enough enzymes: Many people are prescribed a starting dose well below the standard guidelines, and this may not be enough for their specific needs. This is because your body is unique, and what you eat varies from what other people eat. The combination of these two factors means that your dose is not going to be the same as someone else’s, regardless of which “category” of EPI you fall into or even with an identical fecal elastase test result. If you still experience symptoms, you may need to increase your dose of enzymes.
  • Miscalculating enzyme dosing: If you eat a small salad with a few bites of chicken, this is likely a lower fat and lower protein meal, when you compare it to a large hamburger with bacon and cheese and a side of french fries. These meals likely need different doses of enzymes. The dose you start with may work for some of your existing meals, but don’t be surprised if you have symptoms with meals with more protein or more fat than your lower quantity meals. Some people can use the same, fixed dose for all their meals…but that usually means their meals don’t vary a lot. Other people like me can have a wide range of meal quantities, so we adjust our dosing for every meal. (It gets easier over time!)
  • Enzyme timing may be wrong: PERT needs to be taken with the first few bites of a meal, and sometimes additional enzymes are needed if the meal is prolonged. It’s ok if you get halfway through a meal and haven’t taken your enzymes – start taking them then. But don’t take them well before you eat or well after. The point is to get them into your system at the same time that you are eating (or drinking any drink with fat/protein). If you have a 5 course meal at a restaurant that lasts 2 hours, you will need to take more enzymes even if your usual dose would normally cover the total quantity of what you consumed. The fact that it’s so spread out matters. Rule of thumb most people use is 20-30 minutes, so if you’re eating longer than that, you likely need another pill (or more than one more).
  • Other gastrointestinal conditions: Some people have additional digestive issues such as SIBO or other conditions like pancreatitis that have their own symptoms, and it can be challenging to tell what are EPI-specific symptoms due to enzyme dosing or timing issues as opposed to symptoms of these other conditions.

Here are some example scenarios where you might not see the improvements right away:

  • If you eat a hamburger with fries as your first meal, but your prescription is for two pills of 10,000 lipase of PERT. This is unlikely to be enough for the meal, as the standard dose for regular meals is 40-50,000 units; many people need more than that; and this type of meal is higher in fat and protein than a standard meal. Thus, symptoms.
  • If you take your PERT 30 minutes before you eat, even if the dose matches your food perfectly, the timing is off and the enzymes won’t be where they need to be to help digest your food. Thus, symptoms.

Short-Term vs. Long-Term Improvements

Short-Term (Days to Weeks)

Once you find the right PERT dosage, the most noticeable and immediate improvements should occur within your first several meals and across a few days, including:

  • Reduction in diarrhea or loose stools
  • Less bloating and discomfort after eating
  • Improved stool consistency
  • Decreased urgency to use the bathroom

If you are still experiencing symptoms after a few days of consistent PERT use, consider adjusting your dose, especially in the context of looking at what quantity is in your meal. (You’ll find some other tips here walking you through how to look at what’s in your food and how to track it, including tools like PERT Pilot for tracking it on your phone over time.)

Long-Term (Weeks to Months)

While digestion-related symptoms can improve within days, some longer-term health effects take weeks or months to resolve or notice improvements. These include:

  • Nutritional deficiencies: If you have been malabsorbing fats and nutrients for a long time, it may take months of improved digestion to correct deficiencies in fat-soluble vitamins (A, D, E, K), iron, or B12.
  • Weight stabilization: Weight gain or stabilization may occur over weeks to months. (Not everyone gains weight, but if you’re looking for weight gain to occur after you improve digestion with enzymes, it will take some time).
  • Improved energy levels: Once your body starts absorbing nutrients more efficiently, you may notice a gradual increase in energy.

Do some people see improvement on these and other symptoms sooner? Yes! However, it’s different for everyone, so don’t expect every single symptom to magically get better after your first few days on PERT.

How to Know If PERT Is Working for You

The key to determining if PERT is effective lies in tracking your symptoms and adjusting accordingly. Signs that your PERT is working include:

  • Well-formed stools without oiliness or a greasy appearance
  • Normal bowel movement frequency (not too frequent or urgent)
  • Reduction in gas, bloating, and stomach discomfort
  • Gradual improvements in weight and energy levels over time, if those were bothersome to you before

Note a key factor that does NOT tell you if PERT is working for you, which is that changes in fecal elastase score do not tell you anything about whether your enzymes are working for you. Elastase is not affected directly by your enzymes, meaning the elastase test measures human elastase (and enzymes are not human elastase, so they’re not measured by the elastase test). Elastase can naturally fluctuate a bit over time; test precision is not perfect; and for a lot of reasons it’s common to see different numbers in elastase. Read this blog post for a lot more detail, but a change from 23 to 84, or from 154 to 137, or from 58 to 101 are not meaningful changes and do not change the diagnosis of EPI. The categorization of EPI as ‘moderate’ or ‘severe’ does not matter for either diagnosis overall (EPI is EPI) and does not matter for whether or not enzymes are effective because elastase can’t answer that question.

When to Adjust or Reassess Enzyme Dosing

If you do not see some improvements within a few meals or a few days, it may indicate that your dose is too low or not properly timed or you are eating different size meals and need to pay attention to your dose size relative to what you are eating. Work with your healthcare provider to fine-tune your dosage (note that they may not be aware of the guidelines for starting doses or aware that dose ranges vary person to person), and consider tracking your meals and symptoms to identify patterns. Once you’ve ruled that out, say by tracking your meals and increasing your doses and eating consistently sized meals, you may want to investigate other conditions contributing to symptoms.

For most people, PERT should start showing effects within a single meal if the dose is in the ballpark of being correct, even if it’s not fully covering your meal. However, because under-dosing is common, it may take days or weeks of adjustments to see consistent improvement or to improve or eliminate all symptoms.

Immediate symptoms like bloating, diarrhea, and gas should improve quickly (days to weeks), while long-term nutritional recovery (if you had any nutritional deficiencies) may take longer (weeks to months).
A gif showing a square moving along a spectrum from "too little" to "too much enzyme". Too little enzyme and you have symptoms, not enough and you reduce but don't eliminate symptoms. Enough enzymes and you eliminate symptoms. Too much risks constipation.

Other posts you may find helpful:

Beware “too much” and “too little” advice in Exocrine Pancreatic Insufficiency (EPI / PEI)

by Dana Lewis

If I had a nickel every time I saw conflicting advice for people with EPI, I could buy (more) pancreatic enzyme replacement therapy. (PERT is expensive, so it’s significant that there’s so much conflicting advice).

One rule of thumb I find handy is to pause any time I see the words “too much” or “too little”.

This comes up in a lot of categories. For example, someone saying not to eat “too much” fat or fiber, and that a low-fat diet is better. The first part of the sentence should warrant a pause (red flag words – “too much”), and that should put a lot of skepticism on any advice that follows.

Specifically on the “low fat diet” – this is not true. A lot of outdated advice about EPI comes from historical research that no longer reflects modern treatment. In the past, low-fat diets were recommended because early enzyme formulations were not encapsulated or as effective, so people in the 1990s struggled to digest fat because the enzymes weren’t correctly working at the right time in their body. The “bandaid” fix was to eat less fat. Now that enzyme formulations are significantly improved (starting in the early 2000s, enzymes are now encapsulated so they get to the right place in our digestive system at the right time to work on the food we eat or drink), medical experts no longer recommend low-fat diets. Instead, people should eat a regular diet and adjust their enzyme intake accordingly to match that food intake, rather than the other way around (source: see section 4.6).

Think replacement of enzymes, rather than restriction of dietary intake: the “R” in PERT literally stands for replacement!

If you’re reading advice as a person with EPI (PEI), you need to have math in the back of your mind. (Sorry if you don’t like math, I’ll talk about some tools to help).

Any time people use words to indicate amounts of things, whether that’s amounts of enzymes or amounts of food (fat, protein, carbs, fiber), you need to think of specific numbers to go with these words.

And, you need to remember that everyone’s body is different, which means your body is different.

Turning words into math for pill count and enzymes for EPI

Enzyme intake should not be compared without considering multiple factors.

The first reason is because enzyme pills are not all the same size. Some prescription pancreatic enzyme replacement therapy (PERT) pills can be as small as 3,000 units of lipase or as large as 60,000 units of lipase. (They also contain thousands or hundreds of thousands of units of protease and amylase, to support protein and carbohydrate digestion. For this example I’ll stick to lipase, for fat digestion.)

If a person takes two enzyme pills per meal, that number alone tells us nothing. Or rather, it tells us only half of the equation!

The size of the pills matters. Someone taking two 10,000-lipase pills consumes 20,000 units per meal, while another person taking two 40,000-lipase pills is consuming 80,000 units per meal.

That is a big difference! Comparing the two total amounts of enzymes (80,000 units of lipase or 20,000 units of lipase) is a 4x difference.

And I hate to tell you this, but that’s still not the entire equation to consider. Hold on to your hat for a little more math, because…

The amount of fat consumed also matters.

Remember, enzymes are used to digest food. It’s not a magic pill where one (or two) pills will perfectly cover all food. It’s similar to insulin, where different people can need different amounts of insulin for the same amount of carbohydrates. Enzymes work the same way, where different people need different amounts of enzymes for the same amount of fat, protein, or carbohydrates.

And, people consume different amounts and types of food! Breakfast is a good example. Some people will eat cereal with milk – often that’s more carbs, a little bit of protein, and some fat. Some people will eat eggs and bacon – that’s very little carbs, a good amount of protein, and a larger amount of fat.

Let’s say you eat cereal with milk one day, and eggs and bacon the next day. Taking “two pills” might work for your cereal and milk, but not your eggs and bacon, if you’re the person with 10,000 units of lipase in your pill. However, taking “two pills” of 40,000 units of lipase might work for both meals. Or not: you may need more for the meal with higher amounts of fat and protein.

If someone eats the same quantity of fat and protein and carbs across all 3 meals, every day, they may be able to always consume the same number of pills. But for most of us, our food choices vary, and the protein and fat varies meal to meal, so it’s common to need different amounts at different meals. (If you want more details on how to figure out how much you need, given what you eat, check out this blog post with example meals and a lot more detail.)

You need to understand your baseline before making any comparisons

Everyone’s body is different, and enzyme needs vary widely depending on the amount of fat and protein consumed. What is “too much” for one person might be exactly the right amount for another, even when comparing the same exact food quantity. This variability makes it essential to understand your own baseline rather than following generic guidance. The key is finding what works for your specific needs rather than focusing on an arbitrary notion of “too much”, because “too much” needs to be compared to specific numbers that can be compared as apples to apples.

A useful analogy is heart rate. Some people have naturally higher or lower resting heart rates. If someone tells you (that’s not a doctor giving you direct medical advice) that your heart rate is too high, it’s like – what can you do about it? It’s not like you can grow your heart two sizes (like the Grinch). While fitness and activity can influence heart rate slightly, individual baseline differences remain significant. If you find yourself saying “duh, of course I’m not going to try to compare my heart rate to my spouse’s, our bodies are different”, that’s a GREAT frame of mind that you should apply to EPI, too.

(Another example is respiratory rate, where it varies person to person. If someone is having trouble breathing, the solution is not as simple as “breathe more” or “breathe less”—it depends on their normal range and underlying causes, and it takes understanding their normal range to figure out if they are breathing more or less than their normal, because their normal is what matters.)

If you have EPI, fiber (and anything else) also needs numbers

Fiber also follows this pattern. Some people caution against consuming “too much” fiber, but a baseline level is essential. “Too little” fiber can mimic EPI symptoms, leading to soft, messy stools. Finding the right amount of fiber is just as crucial as balancing fat and protein intake.

If you find yourself observing or hearing comments that you likely consume “too much” fiber – red flag check for “too much!” Similar to if you hear/see about ‘low fiber’. Low meaning what number?

You should get an estimate for how much you are consuming and contextualize it against the typical recommendations overall, evaluate whether fiber is contributing to your issues, and only then consider experimenting with it.

(For what it’s worth, you may need to adjust enzyme intake for fat/protein first before you play around with fiber, if you have EPI. Many people are given PERT prescriptions below standard guidelines, so it is common to need to increase dosing.)

For example, if you’re consuming 5 grams of fiber in a day, and the typical guidance is often for 25-30 grams (source, varies by age, gender and country so this is a ballpark)…. you are consuming less than the average person and the average recommendation.

In contrast, if you’re consuming 50+ grams of fiber? You’re consuming more than the average person/recommendation.

Understanding where you are (around the recommendation, quite a bit below, or above?) will then help you determine whether advice for ‘more’ or ‘less’ is actually appropriate in your case. Most people have no idea what you’re eating – and honestly, you may not either – so any advice for “too much”, “too little”, or “more” or “less” is completely unhelpful without these numbers in mind.

You don’t have to tell people these numbers, but you can and should know them if you want to consider evaluating whether YOU think you need more/less compared to your previous baseline.

How do you get numbers for fiber, fat, protein, and carbohydrates?

Instead of following vague “more” or “less” advice, first track your intake and outcomes.

If you don’t have a good way to estimate the amount of fat, protein, carbohydrates, and/or fiber, here’s a tool you can use – this is a Custom GPT that is designed to give you back estimates of fat, protein, carbohydrates, and fiber.

You can give it a meal, or a day’s worth of meals, or several days, and have it generate estimates for you. (It’s not perfect but it’s probably better than guessing, if you’re not familiar with estimating these macronutrients).

If you don’t like or can’t access ChatGPT (it works with free accounts, if you log in), you can also take this prompt, adjust it how you like, and give it to any free LLM tool you like (Gemini, Claude, etc.):

You are a dietitian with expertise in estimating the grams of fat, protein, carbohydrate, and fiber based on a plain language meal description. For every meal description given by the user, reply with structured text for grams of fat, protein, carbohydrates, and fiber. Your response should be four numbers and their labels. Reply only with this structure: “Fat: X; Protein: Y; Carbohydrates: Z; Fiber; A”. (Replace the X, Y, Z, and A with your estimates for these macronutrients.). If there is a decimal, round to the nearest whole number. If there are no grams of any of the macronutrients, mark them as 0 rather than nil. If the result is 0 for all four variables, please reply to the user: “I am unable to parse this meal description. Please try again.”

If you are asked by the user to then summarize a day’s worth of meals that you have estimated, you are able to do so. (Or a week’s worth). Perform the basic sum calculation needed to do this addition of each macronutrient for the time period requested, based on the estimates you provided for individual meals.

Another option is using an app like PERT Pilot. PERT Pilot is a free app for iOS for people with EPI that requires no login or user account information, and you can put in plain language descriptions of meals (“macaroni and cheese” or “spaghetti with meatballs”) and get back the estimates of fat, protein, and carbohydrates, and record how much enzymes you took so you can track your outcomes over time. (Android users – email me at Dana+PERTPilot@OpenAPS.org if you’d like to test the forthcoming Android version!) Note that PERT Pilot doesn’t estimate fiber, but if you want to start with fat/protein estimates, PERT Pilot is another way to get started with seeing what you typically consume. (For people without EPI, you can use Carb Pilot, another free iOS app that similarly gives estimates of macronutrients.)

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Beware advice of "more" or "less" that is vague and non-numeric (not a number) unless you know your baseline numbers in exocrine pancreatic insufficiency. A blog by Dana M. Lewis from DIYPS.orgTL;DR: Instead of arbitrarily lowering or increasing fat or fiber in the diet, measure and estimate what you are consuming first. If you have EPI, assess fat digestion first by adjusting enzyme intake to minimize symptoms. (And then protein, especially for low fat / high protein meals, such as chicken or fish.) Only then consider fiber intake—some people may actually need more fiber rather than less than what they were consuming before if they experience mushy stools. Remember the importance of putting “more” or “less” into context with your own baseline numbers. Estimating current consumption is crucial because an already low-fiber diet may be contributing to the problem, and reducing fiber further could make things worse. Understanding your own baseline is the key.

You Can Create Your Own Icons (and animated gifs)

by Dana Lewis

Over the years, I’ve experimented with different tools for making visuals. Some of them are just images but in the last several years I’ve made more animations, too.

But not with any fancy design program or purpose built tool. Instead, I use PowerPoint.

Making animated gifs

I first started using PowerPoint to create gifs around 2018 or 2019. At the time, PowerPoint didn’t have a built-in option to export directly to GIF format, so I had to export animations as a movie file first and then use an online converter to turn them into a GIF. Fortunately, in recent years, PowerPoint has added a direct “Export as GIF” feature.

The process of making an animated GIF in PowerPoint is similar to adding animations or transitions in a slide deck for a presentation. I’ve used this for various projects, including:

Am I especially trained? No. Do I feel like I have design skills? No.

Elbow grease and determination to try is what I have, with the goal of trying to use visuals to convey information as a summary or to illustrate a key point to accompany written text. (I also have a tendency to want to be a perfectionist, and I have to consciously let that go and let “anything is better than nothing” guide my attempts.)

Making icons is possible, too

Beyond animations, I’ve also used PowerPoint to create icons and simple logo designs.

I ended up making the logos for Carb Pilot (a free iOS app that enables you to track the macronutrients of your choice) and PERT Pilot (a free iOS app that enables people with exocrine pancreatic insufficiency, known as EPI or PEI, to track their enzyme intake) using PowerPoint.

This, and ongoing use of LLMs to help me with coding projects like these apps, is what led me to the realization that I can now make icons, too.

I was working to add a widget to Carb Pilot, so that users can have a widget on the home screen to more quickly enter meals without having to open the app and then tap; this saves a click every time. I went from having it be a single button to having 4 buttons to simulate the Carb Pilot home screen. For the “saved meals” button, I wanted a list icon, to indicate the list of previous meals. I went to SF Symbols, Apple’s icon library, and picked out the list icon I wanted to use, and referenced it in XCode. It worked, but it lacked something.

A light purple iOS widget with four buttons - top left is blue and says AI: top right is purple with a white microphone icon; bottom left is periwinkle blue with a white plus sign icon; bottom right is bright green with a custom list icon, where instead of bullets the three items are an apple, cupcake, and banana mini-icons. It occurred to me that maybe I could tweak it somehow and make the bullets of the list represent food items. I wasn’t sure how, so I asked the LLM if it was possible. Because I’ve done my other ‘design’ work in PowerPoint, I went there and quickly dropped some shapes and lines to simulate the icon, then tested exporting – yes, you can export as SVG! I spent a few more minutes tweaking versions of it and exporting it. It turns out, yes, you can export as SVG, but then the way I designed it wasn’t really suited for SVG use. When I had dropped the SVG into XCode, it didn’t show up. I asked the LLM again and it suggested trying PNG format. I exported the icon from powerpoint as PNG, dropped it into XCode, and it worked!

(That was a good reminder that even when you use the “right” format, you may need to experiment to see what actually works in practice with whatever tools you’re using, and not let the first failure be a sign that it can’t work.)

Use What Works

There’s a theme you’ll be hearing from me: try and see what works. Just try. You don’t know if you don’t try. With LLMs and other types of AI, we have more opportunities to try new and different things that we may not have known how to do before. From coding your own apps to doing data science to designing custom icons, these are all things I didn’t know how to do before but now I can. A good approach is to experiment, try different things (and different prompts), and not be afraid to use “nontraditional” tools for projects, creative or otherwise. If it works, it works!

Facing Uncertainty with AI and Rethinking What If You Could?

by Dana Lewis

If you’re feeling overwhelmed by the rapid development of AI, you’re not alone. It’s moving fast, and for many people the uncertainty of the future (for any number of reasons) can feel scary. One reaction is to ignore it, dismiss it, or assume you don’t need it. Some people try it once, usually on something they’re already good at, and when AI doesn’t perform better than they do, they conclude it’s useless or overhyped, and possibly feel justified in going back to ignoring or rejecting it.

But that approach misses the point.

AI isn’t about replacing what you already do well. It’s about augmenting what you struggle with, unlocking new possibilities, and challenging yourself to think differently, all in the pursuit of enabling YOU to do more than you could yesterday.

One of the ways to navigate the uncertainty around AI is to shift your mindset. Instead of thinking, “That’s hard, and I can’t do that,” ask yourself, “What if I could do that? How could I do that?”

Sometimes I get a head start by asking an LLM just that: “How would I do X? Layout a plan or outline an approach to doing X.” I don’t always immediately jump to doing that thing, but I think about it, and probably 2 out of 3 times, laying out a possible approach means I do come back to that project or task and attempt it at a later time.

Even if you ultimately decide not to pursue something because of time constraints or competing priorities, at least you’ve explored it and possibly learned something even in the initial exploration about it. But, I want to point out that there’s a big difference between legitimately not being able to do something and choosing not to. Increasingly, the latter is what happens, where you may choose not to tackle a task or take on a project: this is very different from not being able to do so.

Finding the Right Use Cases for AI

Instead of testing AI on things you’re already an expert in, try applying it to areas where you’re blocked, stuck, overwhelmed, or burdened by the task. Think about a skill you’ve always wanted to learn but assumed was out of reach. Maybe you’ve never coded before, but you’re curious about writing a small script to automate a task. Maybe you’ve wanted to design a 3D-printed tool to solve a real-world problem but didn’t know where to start. AI can be a guide, an assistant, and sometimes even a collaborator in making these things possible.

For example, I once thought data science was beyond my skill set. For the longest time, I couldn’t even get Jupyter Notebooks to run! Even with expert help, I was clearly doing something silly and wrong, but it took a long time and finally LLM assistance to get step by step and deeper into sub-steps to figure out the step that was never in the documentation or instructions that I was missing – and I finally figured it out! From there, I learned enough to do a lot of the data science work on my own projects. You can see that represented in several recent projects. The same thing happened with iOS development, which I initially felt imposter syndrome about. And this year, after FOUR failed attempts (even 3 using LLMs), I finally got a working app for Android!

Each time, the challenge felt enormous. But by shifting from “I can’t” to “What if I could?” I found ways to break through. And each time AI became a more capable assistant, I revisited previous roadblocks and made even more progress, even when it was a project (like an Android version of PERT Pilot) I had previously failed at, and in that case, multiple times.

Revisiting Past Challenges

AI is evolving rapidly, and what wasn’t possible yesterday might be feasible today. Literally. (A great example is that I wrote a blog post about how medical literature seems like a game of telephone and was opining on AI-assisted tools to aid with tracking changes to the literature over time. The day I put that blog post in the queue, OpenAI announced their Deep Research tool, which I think can in part address some of the challenges I talked about currently being unsolved!)

One thing I have started to do that I recommend is keeping track of problems or projects that feel out of reach. Write them down. Revisit them every few months, and explore them with the latest LLM and AI tools. You might be surprised at how much has changed, and what is now possible.

Moving Forward with AI

You don’t even have to use AI for everything. (I don’t.) But if you’re not yet in the habit of using AI for certain types of tasks, I challenge you to find a way to use an LLM for *something* that you are working on.

A good place to insert this into your work/projects is to start noting when you find yourself saying or thinking “this is the way we/I do/did things”.

When you catch yourself thinking this, stop and ask:

  • Does it have to be done that way? Why do we think so?
  • What are we trying to achieve with this task/project?
  • Are there other ways we can achieve this?
  • If not, can we automate some or more steps of this process? Can some steps be eliminated?

You can ask yourself these questions, but you can also ask these questions to an LLM. And play around with what and how you ask (the prompt, or what you ask it, makes a difference).

One example for me has been working on a systematic review and meta analysis of a medical topic. I need to extract details about criteria I am analyzing across hundreds of papers. Oooph, big task, very slow. The LLM tools aren’t yet good about extracting non-obvious data from research papers, especially PDFs where the data I am interested may be tucked into tables, figure captions, or images themselves rather than explicitly stated as part of the results section. So for now, that still has to be manually done, but it’s on my list to revisit periodically with new LLMs.

However, I recognized that the way I was writing down (well, typing into a spreadsheet) the extracted data was burdensome and slow, and I wondered if I could make a quick simple HTML page to guide me through the extraction, with an output of the data in CSV that I could open in spreadsheet form when I’m ready to analyze. The goal is easier input of the data with the same output format (CSV for a spreadsheet). And so I used an LLM to help me quickly build that HTML page, set up a local server, and run it so I can use it for data extraction. This is one of those projects where I felt intimidated – I never quite understood spinning up servers and in fact didn’t quite understand fundamentally that for free I can “run” “a server” locally on my computer in order to do what I wanted to do. So in the process of working on a task I really understood (make an HTML page to capture data input), I was able to learn about spinning up and using local servers! Success, in terms of completing the task and learning something I can take forward into future projects.

Another smaller recent example is when I wanted to put together a simple case report for my doctor, summarizing symptoms etc, and then also adding in PDF pages of studies I was referencing so she had access to them. I knew from the past that I could copy and paste the thumbnails from Preview into the PDF, but it got challenging to be pasting 15+ pages in as thumbnails and they were inserting and breaking up previous sections, so the order of the pages was wrong and hard to fix. I decided to ask my LLM of choice if it was possible to automate compiling 4 PDF documents via a command line script, and it said yes. It told me what library to install (and I checked this is an existing tool and not a made up or malicious one first), and what command to run. I ran it, it appended the PDFs together into one file the way I wanted, and it didn’t require the tedious hand commands to copy and paste everything together and rearrange when the order was messed up.

The more I practice, the easier I find myself switching into the habit of saying “would it be possible to do X” or “Is there a way to do Y more simply/more efficiently/automate it?”. That then leads to portions which I can decide to implement, or not. But it feels a lot better to have those on hand, even if I choose not to take a project on, rather than to feel overwhelmed and out of control and uncertain about what AI can do (or not).

Facing uncertainty with AI and rethinking "What if you could?", a blog post by Dana M. Lewis on DIYPS.orgIf you can shift your mindset from fear and avoidance to curiosity and experimentation, you might discover new skills, solve problems you once thought were impossible, and open up entirely new opportunities.

So, the next time you think, “That’s too hard, I can’t do that,” stop and ask:

“What if I could?”

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If you appreciated this post, you might like some of my other posts about AI if you haven’t read them.

How Medical Research Literature Evolves Over Time Like A Game of Telephone

by Dana Lewis

Have you ever searched for or through medical research on a specific topic, only to find different studies saying seemingly contradictory things? Or you find something that doesn’t seem to make sense?

You may experience this, whether you’re a doctor, a researcher, or a patient.

I have found it helpful to consider that medical literature is like a game of telephone, where a fact or statement is passed from one research paper to another, which means that sometimes it is slowly (or quickly!) changing along the way. Sometimes this means an error has been introduced, or replicated.

A Game of Telephone in Research Citations

Imagine a research study from 2016 that makes a statement based on the best available data at the time. Over the next few years, other papers cite that original study, repeating the statement. Some authors might slightly rephrase it, adding their own interpretations. By 2019, newer research has emerged that contradicts the original statement. Some researchers start citing this new, corrected information, while others continue citing the outdated statement because they either haven’t updated their knowledge or are relying on older sources, especially because they see other papers pointing to these older sources and find it easiest to point to them, too. It’s not necessarily made clear that this outdated statement is now known to be incorrect. Sometimes that becomes obvious in the literature and field of study, and sometimes it’s not made explicit that the prior statement is ‘incorrect’. (And if it is incorrect, it doesn’t become known as incorrect until later – at the time it’s made, it’s considered to be correct.) 

By 2022, both the correct and incorrect statements appear in the literature. Eventually, a majority of researchers transition to citing the updated, accurate information—but the outdated statement never fully disappears. A handful of papers continue to reference the original incorrect fact, whether due to oversight, habit (of using older sources and repeating citations for simple statements), or a reluctance to accept new findings.

The gif below illustrates this concept, showing how incorrect and correct statements coexist over time. It also highlights how researchers may rely on citations from previous papers without always checking whether the original information was correct in the first place.

Animated gif illustrating how citations branch off and even if new statements are introduced to the literature, the previous statement can continue to appear over time.

This is not necessarily a criticism of researchers/authors of research publications (of which I am one!), but an acknowledgement of the situation that results from these processes. Once you’ve written a paper and cited a basic fact (let’s imagine you wrote this paper in 2017 and cite the 2016 paper and fact), it’s easy to keep using this citation over time. Imagine it’s 2023 and you’re writing a paper on the same topic area, it’s very easy to drop the same citation from 2016  in for the same basic fact, and you may not think to consider updating the citation or check if the fact is still the fact.

Why This Matters

Over time, a once-accepted “fact” may be corrected or revised, but older statements can still linger in the literature, continuing to influence new research. Understanding how this process works can help you critically evaluate medical research and recognize when a widely accepted statement might actually be outdated—or even incorrect.

If you’re looking into a medical topic, it’s important to pay attention not just to what different studies say, but also when they were published and how their key claims have evolved over time. If you notice a shift in the literature—where newer papers cite a different fact than older ones—it may indicate that scientific understanding has changed.

One useful strategy is to notice how frequently a particular statement appears in the literature over time.

Whenever I have a new diagnosis or a new topic to research on one of my chronic diseases, I find myself doing this.

I go and read a lot of abstracts and research papers about the topic; I generally observe patterns in terms of key things that everyone says, which establishes what the generally understood “facts” are, and also notice what is missing. (Usually, the question I’m asking is not addressed in the literature! But that’s another topic…)

I pay attention to the dates, observing when something is said in papers in the 1990s and whether it’s still being repeated in the 2020s era papers, or if/how it’s changed. In my head, I’m updating “this is what is generally known” and “this doesn’t seem to be answered in the literature (yet)” and “this is something that has changed over time” lists.

Re-Evaluating the Original ‘Fact’

In some cases, it turns out the original statement was never correct to begin with. This can happen when early research is based on small sample sizes, incomplete data, or incorrect assumptions. Sometimes that statement was correct, in context, but taken out of context immediately and this out of context use was never corrected. 

For example, a widely cited statement in medical literature once claimed that chronic pancreatitis is the most common cause of exocrine pancreatic insufficiency (EPI). This claim was repeated across numerous papers, reinforcing it as accepted knowledge. However, a closer examination of population data shows that while chronic pancreatitis is a known co-condition of EPI, it is far less common than diabetes—a condition that affects a much larger population and is also strongly associated with EPI. Despite this, many papers still repeat the outdated claim without checking the original data behind it.

(For a deeper dive into this example, you can read my previous post here. But TL;DR: even 80% of .03% is a smaller number than 10% of 10% of the overall population…so it is not plausible that CP is the biggest cause of EPI/PEI.)

Stay Curious

This realization can be really frustrating, because if you’re trying to do primary research to help you understand a topic or question, how do you know what the truth is? This is peer-reviewed research, but what this shows us is that the process of peer-review and publishing in a journal is not infallible. There can be errors. The process for updating errors can be messy, and it can be hard to clean up the literature over time. This makes it hard for us humans – whether in the role of patient or researcher or clinician – to sort things out.

But beyond a ‘woe is me, this is hard’ moment of frustration, I do find that this perspective of literature as a process of telephone makes me a better reader of the literature and forces me to think more critically about what I’m reading, and take papers in context of the broader landscape of literature and evolving knowledge base. It helps remove the strength I would otherwise be prone to assigning any one paper (and any one ‘fact’ or finding from a single paper), and encourages me to calibrate this against the broader knowledge base and the timeline of this knowledge base.

That can also be hard to deal with personally as a researcher/author, especially someone who tends to work in the gaps, establishing new findings and facts and introducing them to the literature. Some of my work also involves correcting errors in the literature, which I find from my outsider/patient perspective to be obvious because I’ve been able to use fresh eyes and evaluate at a systematic review level/high level view, without being as much in the weeds. That means my work, to disseminate new or corrected knowledge, is even more challenging. It’s also challenging personally as a patient, when I “just” want answers and for everything to already be studied, vetted, published, and widely known by everyone (including me and my clinician team).

But it’s usually not, and that’s just something I – and we – have to deal with. I’m curious as to whether we will eventually develop tools with AI to address this. Perhaps a mini systematic review tool that scrapes the literature and includes an analysis of how things have changed over time. This is done in systematic review or narrative reviews of the literature, when you read those types of papers, but those papers are based on researcher interests (and time and funding), and I often have so many questions that don’t have systematic reviews/narrative reviews covering them. Some I turn into papers myself (such as my paper on systematically reviewing the dosing guidelines and research on pancreatic enzyme replacement therapy for people with exocrine pancreatic insufficiency, known as EPI or PEI, or a systematic review on the prevalence of EPI in the general population or a systematic review on the prevalence of EPI in people with diabetes (Type 1 and Type 2)), but sometimes it’s just a personal question and it would be great to have a tool to help facilitate the process of seeing how information has changed over time. Maybe someone will eventually build that tool, or it’ll go on my list of things I might want to build, and I’ll build it myself like I have done with other types of research tools in the past, both without and with AI assistance. We’ll see!

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TL;DR: be cognizant of the fact that medical literature changes over time, and keep this in mind when reading a single paper. Sometimes there are competing “facts” or beliefs or statements in the literature, and sometimes you can identify how it evolves over time, so that you can better assess the accuracy of research findings and avoid relying on outdated or incorrect information.

Whether you’re a researcher, a clinician, or a patient doing research for yourself, this awareness can help you better navigate the scientific literature.

A screenshot from the animated gif showing how citation strings happen in the literature, branching off over time but often still resulting in a repetition of a fact that is later considered to be incorrect, thus both the correct and incorrect fact occur in the literature at the same time.