Objective: Past research provides insufficient evidence to inform second-line diabetes medication prescribing when metformin is no longer sufficient. We evaluated patient, prescriber, and health plan characteristics associated with selection of second-line diabetes medications in the USA.
Research design and methods: We used a multiple case-comparison study design to identify characteristics associated with the probability of starting each of six second-line diabetes medication alternatives within 77 744 adults enrolled in commercial or Medicare Advantage health plans from 2011 to 2015. National administrative data were provided by a large commercial health payer. Multinomial logistic regression models were used to identify characteristics independently associated with selecting each diabetes drug class.
Results: From 2011 to 2015, sulfonylureas still represented 47% of all second-line drug starts, with proportionately higher use in patients ≥75 years of age (63% of drug starts). Basal insulin was more likely to be selected when a past A1c test result was >10% (13.0% vs 4.5% for those with A1c <8%; p<0.001). Initiation of a glucagon-like peptide-1 receptor agonist was associated with being female (10.1% vs 6.0% for male; p<0.001) and having a diagnosis code for obesity (10.8% vs 6.9% for no diagnosis; p<0.001). For all drug classes, the recent prescribing behavior of the provider was a strong correlate of subsequent second-line drug selection.
Conclusions: Sulfonylureas continue to represent almost half of second-line diabetes medication starts in the USA. This could reflect overuse for some groups such as older adults, for whom some alternatives may be safer, although more costly and potentially less effective. Future research should compare outcomes of medication choices and conditions under which particular classes are most effective.
Keywords: case comparison study design; diabetes mellitus; medication utilization; pharmacoepidemiology; type 2.