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Table 2 Identified themes and representative participant quotes

From: Researchers’ perspectives on methodological challenges and outcomes selection in interventional studies targeting medication adherence in rheumatic diseases: an OMERACT-adherence study

Theme

Representative quote

1. Improving measurement of adherence

a. Considering all phases of adherence

“… first of all it’s very important that researchers define exactly the impact on which element of medication adherence, this is very poorly defined typically if it’s improving initiation of treatment, implementation of treatment or persistence to treatment. Secondly choosing the appropriate measurement depending on the elements of adherence and providing the appropriate analysis.”

“Long term the issue has been about measurements because people confuse and conflate various aspects of medication adherence. They talk just using the word adherence, not referring to precisely what it means […] there are three main phases which are initiation, start your first dose, there’s implementation which is what you do from one day to the next, and there’s persistence which is how long you continue on treatment before you give up. And most researchers to date have completely confused those three issues […] I think that’s hindered so much potential progress in adherence research.”

b. Using appropriate and relevant adherence measures

“Well adherence the big issue is that none of the outcomes are perfect. They all have their pros and cons either in terms of feasibility or their validity, sensitivity or specificity and it’s not clear to a researcher what combination of various outcomes should they use to capture that in the context of when they are measuring adherence to, within the study that they are, they are, that they are working on.”

“I think the most challenging is how to measure the adherence because it’s so many ways to measure it but it’s not, not one is the gold standard, we don’t have a gold standard for adherence.”

c. Establishing clinically meaningful thresholds

“..often people use this kind of 80% cutoff and but then when you look at where that comes from […]. So it’s got very, just a relevance to a lot of the clinical condition(s), a lot of the diseases to which that cutoff’s applied. And it might well be that for some conditions and some medications and some patients maybe 60% adherence is fine”

“I think one of the key areas is, is how much adherence you need for an individual to, to have a better result or a good result. I think there’s virtually no work on that that I’m familiar with and it’s very important. Why impose strict adherence criteria on people who may not need it, so in other words, can adherence be individualized?”

2. Challenges in designing and appraising adherence intervention studies

a. Confusion from a plethora of outcomes choices

“I guess you have a kind of whole range of outcomes, so you can have psychological outcomes, say things like anxiety, depression, quality of life, self-reported, self-rated health, […] kind of perspectives on general wellbeing. There’s often measures of health care utilization and so things like attendance at hospital, attendance to primary care, nurse appointments and duration, things like times off work, or not able to undertake other kind of routine responsibilities, […]. And also I guess all the you know […] most relevant clinical outcomes.”

“I would advocate using the EQ-5D quite often because it measures utility that can be used to estimate quality adjusted life years for calculating the cost-effectiveness of healthcare interventions, to assess the value for money of health technologies so I insist on including that, in my clinical trials as an outcome measure for economic analyses. But it depends on the trial. If it’s a trial of 20 patients and […] you just want to check to see if it (the intervention) has an impact on adherence then these would be very low sort of secondary outcomes on that scale. You could also have cost as an outcome […], but I’m interested in seeing whether that intervention represents good value for money.”

b. Difficulty powering studies to demonstrate meaningful changes

“I think one of the major things is often power because for, and kind of related to that is recruitment and in particular, because typically you have quite a large number of people in your sample that are already adherent […] and then recruiting sufficient numbers can be a challenge, particularly given that the people you often most want in your sample are the people who are non-adherent and often the people who are non-adherent are the people who are hardest to recruit.”

“A key challenge though is power because you’d need an enormous study in many of these types of conditions in order to detect the (clinical) difference through improvements in adherence.”

c. Suboptimal description of adherence interventions

“… often the intervention contents are poorly recorded, […] there’s often no systemic use of key terms around the intervention contents so terms such as medication counselling or you know education are used to describe intervention contents and then often can mean lots and lots of different things, so it can be very hard to actually evaluate […] if you’ve got a trial where you’ve got nil results and it says we counselled patients on their medications, it’s very hard to conclude whether it had a nil result because medication counselling doesn’t work or if it’s a particular type of process that doesn’t work, or if often you know there’s all those issues around things like fidelity to protocols, […] so it might be that the intervention itself was beautifully designed but then it wasn’t delivered properly.”

3. Advancing outcome assessment in adherence intervention studies

a. Rationale for a core domain set for adherence intervention studies

“… it will make trials more comparable and it will increase the likelihood that you’d be able to combine efforts internationally or you know with people doing kind of research or benefit work in different contexts. So I think that’s probably likely to increase the strength of the evidence base for what works and which I would hope would increase you know the willingness of policy makers to support services that used whatever the effect or the approach as identified were.”

“I think it’s needed because if, if nothing it’ll give more clarity with regards to the measures, their limitation and how they apply to […] our conditions and will bring a lot of attention to, attention and emphasis to, to context and design sort of issues.”

b. Prioritizing outcome for a core domain set for adherence intervention studies

“it would be important to include some sort of patient centered outcome, you know some sort of objective measure of adherence ideally. We triangulate adherence ideally from a couple of different measurement perspectives so you know self-report we know has some real advantages in that we’re able to determine barriers or reasons for non-adherence but certainly patients on average tend to over-report their adherence.”

“ultimately it’s the clinical outcome that relate to quality of life and survival that matter to the patient […] That hasn’t been done extensively. There are many examples in hypertension where they’ve assessed blood pressure perhaps as an intermediary clinical outcome but not necessarily anything more than that.”

“what matters is the clinical. It may affect someone’s adherence and that’s very interesting but does it actually give them better control of their disease? It doesn’t matter if it changes their adherence, it only matters whether the patient has a good clinical outcome from it.”

“Well it would depend on the design of the intervention so depending on how the intervention […] I would want to see those outcomes, those assessed and reported as outcomes. So for example, if it was an education intervention that’s designed to increase knowledge, I would want to see a measure of knowledge as one of the outcome measures or if it was an intervention that was designed to increase social support for medication taking, I would want to see a measure of you know perceptions of social support.”

c. Challenges in developing and implementing a core domain set for adherence intervention studies

“Context is also critically important, and I think generally not assessed well in the literature. There are often some practical limitations in data availability so if we’re doing things that are recruiting patients from the community, we might not have access to things like electronic health records or certainly certain countries don’t have access to electronic health record data so all of those things might impact how we would design outcome data collection.”

“I think as a clinician my, the context for me is can I help to improve patients’ disease control. The context for a pharmaceutical company looking to improve adherence may be with a patient support program, it may be different, that might be about health economics for example and it also depends on what country and how the, what the economic model is for delivering healthcare in the country.”

“The issue is very much to do with you know what’s the intention of the trial, is it a definitive study to show that so when an intervention let’s say has a demonstrable impact on health and outcomes or in the smaller scales do they to just check to see whether intervention has efficacy in improving adherence.”

“I would just be clear on when and why you’re doing this, what the consequences and, and rewards are. And you know then if people chose not to do that that you know that’s, that’s something that they can do in an informed way.”

d. Inclusivity and representativeness of a core domain set for stakeholders in adherence intervention research

“… to get buy in so that always in these things the stakeholder involvement early on in making likely that it’s representative, which is very hard to do, but that’s I think being open and transparent about that and allowing it as a sort of an open source approach to a useful set of guidance if you like. I think getting the companies, regulators, patient groups, together to really support this and be enthusiastic’s a huge job.”

“was thinking that still I believe in the core set but you can look at different points or different, with different glasses through that core set because sometimes as a researcher you have a glass looking at the effects of an intervention but also the mechanism, the […] effect whereas if you look at, from the patient point of view, you would like to know what means it for me as patients and they’re less interested in the mechanism behind it and clinicians tend to look mostly at the clinical aspects. So each of, of, of different point of view you have different demands from this core set.”