Clinical inertia in people with type 2 diabetes: a retrospective cohort study of more than 80,000 people

Abstract

Objective: To determine time to treatment intensification in people with type 2 diabetes treated with one, two, or three oral antidiabetes drugs (OADs) and associated levels of glycemic control.

Research design and methods: This was a retrospective cohort study based on 81,573 people with type 2 diabetes in the U.K. Clinical Practice Research Datalink between January 2004 and December 2006, with follow-up until April 2011.

Results: In people with HbA1c ≥7.0, ≥7.5, or ≥8.0% (≥53, ≥58, or ≥64 mmol/mol), median time from above HbA1c cutoff to intensification with an additional OAD was 2.9, 1.9, or 1.6 years, respectively, for those taking one OAD and >7.2, >7.2, and >6.9 years for those taking two OADs. Median time to intensification with insulin was >7.1, >6.1, or 6.0 years for those taking one, two, or three OADs. Mean HbA1c at intensification with an OAD or insulin for people taking one, two, or three OADs was 8.7, 9.1, and 9.7%. In patients taking one, two, or three OADs, median time from treatment initiation to intensification with an OAD or insulin exceeded the maximum follow-up time of 7.2 years. The probability of patients with poor glycemic control taking one, two, or three OADs, intensifying at end of follow-up with an OAD, was 21.1-43.6% and with insulin 5.1-12.0%.

Conclusions: There are delays in treatment intensification in people with type 2 diabetes despite suboptimal glycemic control. A substantial proportion of people remain in poor glycemic control for several years before intensification with OADs and insulin.

Figure 1

Time (years) from HbA_1c >7, 7.5, and 8% (53, 58, and 64 mmol/mol, respectively) to intensification by one OAD (n = 35,988, 31,375, and 25,096) (A), two OADs (n = 21,858, 20,164, and 16,991, respectively) (B), and three OADs (n = 5,050, 4,733, and 4,112, respectively) (C). (Note: for three OADs, no regimen was intensified with an additional OAD.) For OAD, the probability is estimated as 1 minus cumulative incidence function for intensification; for insulin, the probability is estimated as 1 minus cumulative incidence function for intensification. For OAD or insulin, the probability is estimated as 1 minus sum of the cumulative incidence function for OAD and insulin.

Figure 2

Time (years) from start of regimen to intensification by one OAD (n = 50,476) (A), two OADs (n = 25,600) (B), and three OADs (n = 5,677) (C). (Note: for three OADs, no regimen was intensified with an additional OAD.) For OAD, the probability is estimated as 1 minus cumulative incidence function for intensification; for insulin, the probability is estimated as 1 minus cumulative incidence function for intensification. For OAD or insulin, the probability is estimated as 1 minus sum of the cumulative incidence function for OAD and insulin.