Time to Treatment Intensification in Newly Treated Adult Type 2 Diabetes Patients: Comparison of Canada and the United States

Abstract

ObjectivesOur aim in this study was to determine whether differences exist in time to treatment intensification in newly treated type 2 diabetes patients in Canada and the United States (US). MethodsTwo separate retrospective cohorts of diabetes patients were used from Canada and the US. Time to treatment intensification (i.e. addition of a second antihyperglycemic agent after initial metformin use) was determined using multivariate Cox proportional hazard models. ResultsAmong new metformin users in 2004‒2007 (2,116 Canadians and 2,631 Americans) >65 years of age, the median time to treatment intensification was 362 days for Canadians and 170 days for Americans (adjusted hazard ratio, 1.99; 95% confidence interval, 1.69 to 2.36). In a second cohort of all adult ages with clinical data between 2008 and 2010 (23,022 Canadians and 19,318 Americans), the median time to treatment intensification was 197 days for Canadians and 119 days for Americans (adjusted hazard ratio, 5.62; 95% confidence interval, 5.246 to 6.029). At treatment intensification, the mean glycated hemoglobin was 9.0% (standard deviation, 2.0) in Canada and 8.6% (standard deviation, 2.2) in the US (p<0.01). ConclusionsAlthough clinical practice guidelines are similar between Canada and the US, Canadian clinicians have historically demonstrated more clinical inertia compared with their US counterparts with respect to intensifying antihyperglycemic therapy. It is relatively unknown whether these differences currently exist or whether Canadian clinicians have closed the gap.