Evaluating patient adherence to medication regimens for chronic disease

The brief

A research agency needed to understand why patients on long-term medication for chronic conditions stop taking it as prescribed, across six markets with very different health systems. The study needed both a quantitative measure of adherence behaviour and qualitative depth on the reasons behind it.

The problem

Patients with the specified conditions were reachable, but adherence is a sensitive subject and self-reported adherence is known to be over-stated. A straightforward survey question would have produced a comfortable number and no insight.

What we did

• Recruited through patient advocacy networks and clinical referral rather than general panel supply
• Measured adherence behaviourally — refill timing, missed-dose recall against a fixed window — rather than by direct self-report
• Ran 40 in-depth interviews alongside the survey, with the same respondents where consent allowed
• Applied local-language interviewers in every market, with safeguarding briefing on disclosure of clinical distress

The outcome

Behavioural measurement produced adherence estimates materially lower than the self-reported figures collected in the same interview, and the interview work explained the gap: most non-adherence was intentional and reasoned rather than forgetful, and it clustered around side-effect management.

The agency was able to present a finding their client could act on, with the method documented well enough to survive the client's internal review.