Adherence

Adherence refers to the extent to which a person’s behavior aligns with agreed recommendations from a health professional. In clinical contexts it most often concerns taking medications as prescribed, but it also includes following dietary restrictions, completing prescribed therapies, and maintaining recommended lifestyle changes.

Adherence is distinct from compliance in that it emphasizes collaboration between patient and clinician. It covers a range of behaviors, including medication-taking, attending appointments, and following rehabilitation or preventive regimens over time.

Adherence can be categorized as intentional or unintentional. Intentional adherence arises from choices based on beliefs, values, or perceived risks and benefits. Unintentional nonadherence results from forgetfulness, misunderstanding, or practical barriers such as cost, access, or complex dosing schedules.

Measurement of adherence uses methods such as patient self-report, pharmacy refill data, electronic monitoring, and pill counts. Each method has limitations, and adherence is often viewed as a continuous spectrum rather than a binary state. Persistence, the duration of continued therapy, is closely related to adherence and helps distinguish early discontinuation from intermittent nonadherence.

Factors influencing adherence include patient factors (health literacy, beliefs about illness and treatment), regimen factors (complexity, dosing frequency, side effects), and system factors (costs, access, clinician-patient relationship). Interventions to improve adherence typically aim to simplify regimens, provide reminders, enhance education, support shared decision making, address financial and access barriers, and foster ongoing patient engagement.

Overall, adherence is a critical determinant of treatment effectiveness and health outcomes, with better adherence generally linked to improved clinical results and reduced healthcare costs.