Uncovering the Predictors of Nonadherence to Insulin Therapy Among Patients With Type 1 and Type 2 Diabetes Attending an Endocrinology Outpatient Clinic of a Tertiary Care Hospital

<h2>Abstract</h2><h3>Background/Objective</h3> Nonadherence to insulin therapy remains a major challenge to achieving optimal glycemic control, leading to complications and increased healthcare costs. Despite accessible insulin therapy in tertiary hospitals, barriers such as injection fear, complex regimens, inadequate storage, stigma, and limited health literacy contribute to poor adherence. Evidence on determinants of insulin nonadherence in tertiary care settings in India remains limited. This study aimed to determine the prevalence and predictors of insulin nonadherence among adults with diabetes mellitus. <h3>Methods</h3> A cross-sectional survey was conducted from February to July 2025 among adults (≥18 years) with type 1 or type 2 diabetes mellitus receiving insulin therapy for at least 6 months, selected using a consecutive sampling technique. The 8-item Morisky Medication Adherence Scale (MMAS-8) assessed adherence; scores <6 indicated nonadherence. Data were analyzed using SPSS version 29, and binary logistic regression identified independent predictors. <h3>Results</h3> Of 402 participants, 36.8% were nonadherent. Independent predictors of nonadherence included upper-middle socioeconomic status (AOR 2.11; 95% CI 1.07–4.15; p=0.031), type 2 diabetes (AOR 2.23; 95% CI 1.20–4.14; p=0.011), lack of insulin storage (AOR 4.72; 95% CI 2.28–9.76; p<0.001), polypharmacy (AOR 4.00; 95% CI 0.99–16.14; p=0.046), and poor lifestyle adherence (AOR 1.62; 95% CI 0.95–2.77; p=0.047). Primary education was associated with lower odds of non-adherence (AOR 0.26; 95% CI 0.08–0.83; p=0.023). <h3>Conclusion</h3> Over one-third of patients were nonadherent to insulin therapy. Findings highlight the need for focused educational support, behavioural counseling, and structural solutions such as improved storage provisions to enhance adherence and metabolic outcomes.