Sara Horst, MD, on Medication Adherence Among Patients With IBD
Dr Horst cautions that physicians often believe their patients with inflammatory bowel disease are more adherent to their medication regimens than they are. She discusses the facts about medication adherence and how to help patients become more compliant.
Sara Horst, MD, is a gastroenterologist from Vanderbilt University Medical Center and Section Editor in inflammatory bowel disease for the Gastroenterology Learning Network.
Hello. I'm Sara Horst, a gastroenterologist at Vanderbilt University Medical Center in Nashville, Tennessee, who specializes in the care of patients with IBD. I would like to talk today about an issue I'm interested in, which is medication adherence in patients with IBD.
Now, medication adherence can be a big deal. Studies have shown nonadherence leads to clinical relapse and treatment failure for both oral and injectable infusion medications in patients with IBD. Nationally, overall medication adherence is frankly not good in the US. It averages about 50%. We as doctors think that patients are doing better than they are. One study showed providers overestimated adherence for their patients by at least 20%.
How adherence is measured is even difficult, so it can make studying it hard. Newer data often relies on pharmacy fill data. You might see rates like medication possession ratio or portion of days covered in newer studies.
Data on medication adherence is a little sparse in IBD, but it's getting better. Prior work around oral 5‑ASA medicines showed a nonadherence rate between 30% and 45%, which feels pretty high.
The next important thing to think about is which patient is at risk for nonadherence. Again, this literature is a little bit heterogeneous, but patient factors include lack of understanding and education about why they need to take their medications regularly, younger patients, and patients with psychiatric disease, to name just a few.
Probably the biggest risk factor when you're thinking about oral nonadherence rate involves complex dosing regimens, especially if it's more than once daily. A lot of work has gone into helping us as providers understand how important it is to simplify this for patients, as well as formulary options going to once‑daily dosing, which has been helpful for our patients.
The next group of medicines to think about in adherence are biologic medicines. We've learned the importance of keeping adherence to these medicines to keep therapeutic drug levels, especially for anti‑tumor necrosis factor medications, where up to one‑third of our patients could develop antibodies to the medicines and render them less effective.
Nonadherence and low drug levels, obviously, increase this risk. The good news is that biologic medication adherence in IBD seems to be higher than overall medication adherence, with data suggesting adherence between 50% and 80%. But that's still a pretty wide range.
I think one of the things I learned when thinking about this literature is, what is the optimal adherence rate for biologics? A very nice recent national healthcare database study looked at adherence to subcutaneous biologics, anti‑TNFs in particular, and found a nice cutoff marker for adherence, which was an MPR of about 0.85. Patients who had adherence below that rate had increased risk of prednisone use and hospitalizations, which are endpoints for our patients with IBD that we really care about.
Now, this is a little bit higher than a usual generic MPR of 0.8 that a lot of older studies have used. This would equate to being about 2 to 3 days late on a subcutaneous biologic medication at every dose. That's not a lot. That has to be pretty tightly kept close for your patient.
What's really intriguing about this is that using that adherence cutoff reach, the national average of adherence for sub-q biologics was only about 55% to 60 %, which is not great, right? Recently, our group looked further into this to see about risk factors for nonadherence to subcutaneous biologics, so who was going to be nonadherent.
The good news is that, in our multicenter group, we had a little bit higher rates of adherence, so about 70% overall. A multicenter team approach with high patient advocacy is likely helpful. However, even within our population, we found that some patients only had 40% adherence rates.
We found that adherence seemed to be mostly affected by psychological factors or social factors or medication history factors, like smoking, psychiatric history, prior biologic use, or chronic opiate use. Severity of disease or disease characteristics really didn't seem to matter. Also, adherence dropped the more risk factors the patient had.
So how do we fix this? In terms of medication adherence improvement in IBD, prior data has shown improvement involves patient education. When a patient understands that adherence can alter their disease course, they tend to be more adherent.
Also, studies show that the more support a patient has, such as with pharmacy interventions for education and reminders, the more adherent the patient was. As research continues for this, there is more data emerging about the field of behavior change and how this may be needed to push the needle more towards approved adherence at an individual level.
However, I think in the short term, a simple thing for physicians and providers to remember is that our patients are not as adherent as we think they are. We need to remain vigilant about educating patients about taking their medications all the time, not just when they feel poorly, and how adherence can prevent recurrence of disease.
So when they come back for routine follow‑up, even when they're doing well, continuing to focus on education to medication adherence can be important. We need to try to continually improve our understanding of who's at risk for nonadherence, and perhaps focus more resources towards that group in the future.