Insulin adherence and persistence among Chinese patients with type 2 diabetes: a retrospective database analysis

OBJECTIVE: To assess adherence and persistence to insulin therapy and identify its associated factors among Chinese insulin-naïve patients with type 2 diabetes (T2D). METHODS: Tianjin Urban Employee Basic Medical Insurance claims database was used (2008–2011). Adult patients with T2D who initiated insulin therapy during January 2009 through December 2010 and were continuously enrolled for 12 months pre-(baseline) and 12 months post-initiation (follow-up) were included. Patients who had a ≥80% medication possession ratio were deemed adherent, while patients who had no gaps of ≥90 days in insulin therapy were deemed persistent. Associated factors of insulin adherence and persistence were detected by univariate and multivariate analyses. RESULTS: A total of 24,192 patients were included; the patients had a mean age of 58.9 years, with 49.5% being female. About 51.9% of the patients had human insulin as initiation therapy, while 39.1% were initiated with insulin analog and 9.0% with animal-derived insulin. Premixed insulin (77.3%) was prescribed most often in comparison with basal (11.8%) and prandial (10.9%) insulin. Only 30.9% of patients were adherent, and the mean (standard deviation) medication possession ratio was 0.499 (0.361). About 53.0% of patients persisted insulin therapy during follow-up, and the mean time to nonpersistence was 230.3 (145.5) days. Patients initiated with analog were more likely to be adherent (adjusted odds ratio: 1.07, P=0.036) and persistent (adjusted hazard ratio: 0.88, P<0.001) compared with those initiated with human insulin. Patients initiation with basal insulin had lower adherence relative to premixed (adjusted odds ratio: 0.79, P<0.001). Patients comorbid with hypertension or dyslipidemia, initiated with prandial insulin, and with baseline severe hypoglycemic events were more likely to be nonadherent/nonpersistent. CONCLUSION: The insulin adherence and persistence among Chinese patients with T2D are generally poor. Initiation with insulin analog or premixed insulin may result in better adherence/persistence to insulin therapy.