Medication Adherence in Chronic Disease: Determinants, Measurement, Consequences and Evidence-Based Interventions

Abstract

Objective: To synthesize evidence on the terminology, epidemiology, conceptual models, measurement, disease-specific patterns, clinical and economic results, determinants, and evidence-based interventions relevant to medication adherence in persistent disease, incorporating India and other low- and middle-income settings.

Methods: A narrative review was conducted following SANRA principles. PubMed, Scopus, supplemented by hand-searching reference lists of fundamental evaluations and by consulting WHO and Global Initiative for Asthma plan documents. Search conditions combined “medication adherence,” “adherence,” “concordance,” and “persistence” with disease- and intervention-specific conditions; methodical and organized evaluations, meta-analyses, and landmark primary studies were prioritized for inclusion.

Outcomes: Long-term adherence to prescribed therapy in developed countries remains adjacent to 50%, and are frequently reduced in resource-limited settings. The World Health Organization (WHO) five-dimension model; patient-related, condition-related, therapy-related, health-system-related, and socioeconomic aspects; remains the predominant and prevailing organising framework. No single measurement procedure is a gold standard; impartial and unbiased and self-reported methods each include distinct trade-offs between accuracy and practicality. Multi-component interventions unifying education, behavioural support, regimen simplification, and digital condition instruments generate the most steady and regular, if modest, improvements. Indian evidence shows adherence for hypertension and type 2 diabetes frequently below worldwide averages, driven significantly by out-of-pocket medication costs.

Conclusion: Non-adherence is best approached as a flexible, multifactorial clinical problem instead than a corrected patient trait. Individualised, technology-enabled, team-based care, combined with structural interventions tackling cost and entry, provides the most encouraging path to closing the adherence gap, especially in India.