Aims: We investigated the failure of monotherapy in patients with type 2 DM in real practice settings.
Methods: The Korea National Diabetes Program was a prospective, multicenter observational cohort study of type 2 DM patients in Korea. Of the 3,950 patients enrolled in the study, we studied 998 who were continuously maintained on monotherapy for at least 90 days at six participating centers. To balance the baseline characteristics of patients in each group, we employed propensity-matching at a 1:1 ratio (metformin vs. sulfonylureas) and 4:1 ratios (metformin vs. meglitinides and metformin vs. alpha-glucosidase inhibitors [aGIs]). The hazard ratios of treatments (compared with metformin) were determined via Cox’s proportional hazards regression modeling.
Results: The median follow-up time was 56 months and monotherapy failed in 45% of all patients. The annual incidences of failure were 15.6%, 21.3%, 27%, and 9.6% in the metformin, sulfonylurea, meglitinide, and aGI groups. Compared with metformin, sulfonylureas and meglitinides were associated with higher risks of monotherapy failure (HR 1.39, CI 1.08–1.80; HR 1.92, CI 1.13–3.27) and aGIs with risk similar to that of metformin (HR 0.80, CI 0.44–1.45). When analyzed by failure type, sulfonylureas, meglitinides and aGIs were associated with a higher risk of a switch to other agents (HR 4.43, CI 2.14–9.17; HR 18.80, CI 6.21–56.93; HR 4.25 CI 1.49–12.13) and aGIs with a lower risk of prescription of add-on second agents (HR 0.16, CI 0.04–0.64).
Conclusions: Metformin was associated with a lower failure risk than were sulfonylureas and meglitinides, but a comparable aGI failure rate.
