Polypharmacy & Probability: Why the Numbers Matter
I spend a fair bit of time looking at medical literature. Studies are drier than a well-done steak, and packed with a complex gristle of acronyms. AE, CI, T1/2, PRN, RCT… there are a whole lot. A particularly important one, though, I had to learn while doomscrolling Youtube. That was NNT, the Number Needed to Treat.
The field of medical statistics doesn’t come up often in casual conversation, but I don’t think I’m the only one who wasn’t aware of NNT. As it turns out, despite its value as a patient-centered evaluation of treatment efficacy, it’s often improperly used in studies or ignored completely.
So, let’s explore NNT, what it is, and why you should know it.
NNT: Numbers Nerds Treasure
The Number Needed to Treat (NNT) is the kind of statistic that makes doctors squirm a little. It asks, “Okay, but how many people does this drug actually help?” Here’s how it works: let’s say we have a hundred patients taking the fancy new drug ‘Confidenz’ to prevent dying from embarrassment. In a study’s control group, 50 people are given nothing, and 50 take Confidenz. They discover that in the control group 10 people die from embarrassment when leaving the toilet with paper stuck to their pants. But for those who take Confidenz, only 8 die.
Conflidenz’s manufacturer wants to sell the product, so they’ll tell you and the doctor that their drug reduces the risk of death by embarrassment by 20% - because 8 is twenty percent less than 10. But this ignores the 90 people who were completely unaffected. Taking the entire study population into account, that 20% drops to just 2%.
Not so dramatic, but hey! Two percent more alive people is great! The rub comes when you consider side effects and drug interactions. If, for instance, 4% of people who take Confidenz experience spontaneous combustion, that’s two times the likelihood than you benefiting from the drug. In this extreme example, you’re mor likely to die by conflagration than by embarrassment (which is probably also true to real life).
Let’s illustrate this with a real-world example. Statins, like Lipitor, are among the most prescribed drugs in the world. They lower cholesterol and are supposed to prevent heart attacks and strokes. But for people at low risk, the numbers are less impressive.
Here’s the breakdown: about 217 people need to take a statin for one person to avoid a nonfatal heart attack (NNT = 217). For strokes, the number climbs to 313. Now, let’s talk side effects. Roughly one in 21 people will develop muscle pain, and one in 204 will get diabetes they didn’t sign up for. Which means if you’re low-risk, you could easily be one of the folks stuck with the side effects rather than the benefits. Ten times more likely.
Jagged Little Pill
Nearly half of all Americans take at least one prescription drug every month, and about one in four take four or more every single day. Even more eye-opening, kids born in 2019 are expected to spend almost half their lives on medications. For women, it’s closer to 60 percent. Forget apple pie, prescriptions might be the most American thing around.
Now, remember those odds for statins above? If you’re taking four medications, those risks for side effects and adverse events compound. Here’s a frightening statistic: Adverse drug events—overdoses, drug interactions, allergic reactions, etc—are now estimated to be the third leading cause of death in the U.S. That’s about 250,000 to 300,000 deaths every year. Only heart disease and cancer beat it.
Polypharmacy, which is science for “taking a ton of meds at once,” makes things worse. People on 5 to 9 prescriptions have a 50 percent chance of experiencing a drug interaction. If you’re on 20 or more (yes, that’s a real thing), the risk hits 100 percent. That’s right: guaranteed. And among older adults, almost half are already taking five or more medications.
If you’re thinking, “Wow, that sounds dangerous,” you’re not wrong. It’s one reason polypharmacy accounts for nearly a third of all hospital admissions.
Thanks for all the Depression. Now what?
So, what’s a person to do in this sea of pills and statistics? Start with curiosity. Ask your doctor: “What’s the NNT for this drug?” and “What’s the risk of harm?” These are smart questions to ask, and if your doctor doesn’t want to answer, that should tell you something.
Consider a “spring cleaning” with your doctor or pharmacist, especially if you’re taking four or more medications. It’s called deprescribing, and it’s an essential part of effective medical practice. Ask which medications can be safely tapered or removed, and whether they are likely to be helping at all.
The truth about medications is both sobering and empowering. NNT reminds us that not every pill works for every person, and adverse drug events remind us that “more” isn’t always better. At the same time, being informed can make all the difference. The next time you’re considering a new treatment or medication, look at the numbers, and make sure the odds are ever in your favor.
If you’d like help discovering your body condition, or optimizing your health to make the most of the season, come in to the clinic for a visit. Herbal medicines and acupuncture can protect against latent pathogens as well as correct internal imbalances. Call us at (786) 514-3942 or schedule online.
References
CivicScience. (2025, February). More Americans are taking 4+ prescriptions daily. Voices for Affordable Health. https://voicesforaffordablehealth.com/more-americans-are-taking-4-prescriptions-daily/
CivicScience. (2025). Trend to watch: The percentage of Americans taking four or more prescription medications daily continues to rise. https://civicscience.com/trend-to-watch-the-percentage-of-americans-taking-four-or-more-prescription-medications-daily-continues-to-rise/
Ho, J. (2023, October 6). Americans born in 2019 can expect to spend half their lives taking prescription drugs. Penn State News. https://www.psu.edu/news/research/story/americans-will-spend-half-their-lives-taking-prescription-drugs-study-finds
Martin, A., et al. (2019). Life course patterns of prescription drug use in the United States. Demography. https://pmc.ncbi.nlm.nih.gov/articles/PMC10656114/
Martin, A., et al. (2019). Nearly half of people in the United States use prescription drugs over a month. U.S. Pharmacist. https://www.uspharmacist.com/article/nearly-half-of-people-in-united-states-use-prescription-drugs-over-a-month
National Health and Nutrition Examination Survey. (2015–2016). Prescription drug use amongadults aged 40–79. CDC Data Brief. https://www.cdc.gov/nchs/products/databriefs/db347.htm
U.S. Pharmacist. (2016). Polypharmacy. American Pharmacist. https://www.uspharmacist.com/article/polypharmacy
Verywell Health. (2023). Is it time to review the medications you take? Verywell Health. https://www.verywellhealth.com/is-it-time-to-review-the-medications-you-take-7568542
Kaiser Family Foundation. (2024). Public opinion on prescription drugs and their prices. KFF. https://www.kff.org/health-costs/public-opinion-on-prescription-drugs-and-their-prices
CDC via Health.com. (2023). CDC report: 9 million Americans not taking medications as prescribed due to cost. Health.com. https://www.health.com/drug-costs-united-states-cdc-
