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

To assess adherence and persistence to insulin therapy and identify its associated factors among Chinese insulin-naïve patients with type 2 diabetes (T2D).

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.

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.

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.