Therapeutic Inertia in Patients Treated with Two or More Antidiabetics in Primary Care: Factors Predicting Intensification of Treatment

Aims: To determine the patterns and predictors of treatment intensification in patients with type 2 diabetes on ≥2 non-insulin antidiabetic drugs (NIADs) and inadequate glycaemic control in primary care in Catalonia, Spain.

Material And Methods: This was a retrospective analysis using electronic medical records from patients with HbA1c ≥ 7% and a first prescription for a new NIAD or insulin recorded from January 2010 to December 2014. Therapeutic inertia was defined as no intensification if HbA1c was ≥8% at baseline or during follow-up. Time to first intensification was evaluated by time-to-event analysis, and factors predicting intensification through a competing-risk regression model.

Results: Among 23 678 patients with HbA1c ≥ 7%, 26.2% were censored without treatment intensification after a median follow up of 4.2 years. Among the 12 730 patients in the subgroup with HbA1c ≥ 8% at baseline or during follow-up, therapeutic inertia was present in 18.1% of cases. In the overall cohort, mean HbA1c at initiation of insulin and NIAD were 9.4% ± 1.5% and 8.7% ± 1.3%, respectively. Median time to first intensification was 17.1 months in patients with HbA1c 8.0% to 9.9%, and 10.1 months in those with HbA1c > 10%. Variables strongly associated with intensification were HbA1c values 8.0% to 9.9% (subhazard ratio [SHR], 1.7; 95% CI, 1.65-1.78) and >10% (SHR, 2.5; 95% CI, 2.37-2.68); diabetes duration ≥20 years (SHR, 1.25; 95% CI, 1.11-1.41) and, to a lesser extent, female gender, presence of comorbidities, chronic kidney disease and microvascular complications.

Conclusions: Intensification was not undertaken in 1 in 5 patients. Both HbA1c thresholds and time until therapy intensification exceeded current recommendations.