Associated factors to insulin adherence in type 1 diabetes in Tehran and Karaj, Iran

Purpose Type 1 diabetes mellitus (T1DM) is a chronic metabolic disorder, and its prevalence and incidence are increasing globally. Insulin therapy is the basis of T1DM management that can prevent numerous complications. Identifying and resolving the factors involved in patients’ non-adherence can reduce complications, mortality, and economic burden. Methods In this cross-sectional study, a sample of patients with T1DM were included from Alborz and Tehran cities of Iran in 2020. Patients filled the questionnaires consisting of sociodemographic and diabetes characteristics, weight and height measurements, 8-item Morisky Medication Adherence Scale (MMAS), and barriers to insulin therapy. Patients with < six scores of MMAS were considered to have low adherence, while ≥ 6 scores showed moderate/high adherence. Data were analyzed using SPSS, and a P-value of less than 0.05 was considered statistically significant. Results 189 patients with T1DM with a mean (± SD) age of 17.95 (± 10.98) years were enrolled in the study, and 73.5% of patients had moderate/high adherence to insulin therapy. Younger age and owning insurance were significantly associated with being classified in the higher adherence group. The barriers that were significantly associated with non-adherence were forgetting to buy, physician inaccessibility, cost, exhaustion from the long-term injection, forgetfulness, injection site reaction, and rebellion against parents in the < 20 years age group. The main barriers in ≥ 20 years age group were forgetting to buy and insufficient injection instruction. Conclusion The identified barriers to insulin injection would be helpful for policymakers and clinicians to increase insulin adherence among patients with T1DM.