Treatment adherence in acne vulgaris: systematic review and narrative synthesis

Acne vulgaris is common and has a substantial impact on patients' quality of life. Low adherence to acne treatments is a barrier to successful management.

To examine the prevalence of adherence to oral and topical treatments for acne, factors associated with adherence and reasons for nonadherence.

We included primary quantitative studies that investigated acne-related experiences and behaviours, including predictors, determinants and outcomes associated with treatment adherence. We searched the following databases from inception until 24 March 2025, with no language restrictions: MEDLINE, PubMed, Embase, PsycINFO and CINAHL. Quality was appraised using the Mixed Methods Appraisal Tool. We present the findings related to observational studies, analysed using narrative synthesis.

Twenty-six eligible papers reported studies in the Americas, Europe and Asia. Thirteen papers reported quantitative descriptive studies (8111 survey participants plus 2 studies that reported data from electronic health records) and 13 papers (12 studies, 37 884 participants) reported other designs such as analytic cross-sectional or cohort studies. Methods for evaluating adherence varied: 21 studies used self-report with differing questionnaire designs, 3 used prescription data to evaluate medication possession ratio, 3 assessed drug refills, 1 carried out database drug survival analysis and 1 used pill count or tube weighing. Four studies used more than one method. The prevalence of adherence estimates varied from 6% to 84%, with larger studies estimating 50-65% adherence. Adherence was lower among younger people, but there was inconsistent evidence for differences between men and women, or between topical and oral treatments. Reasons for nonadherence included cost, side effects, perceived treatment ineffectiveness or symptom resolution.

Improving treatment adherence in acne remains a priority, particularly for younger people. Interventions addressing the management of side effects and time to effectiveness of treatments may be beneficial.