Cardiovascular disease risk and the time to insulin initiation for Medicaid enrollees with type 2 diabetes

AIMS: We evaluated the relationship between the timing of insulin initiation and cardiovascular diseases (CVD) risk in Pennsylvania Medicaid enrollees with type 2 diabetes (T2D). METHODS: We included 17,873 enrollees (age 47.4 ± 10.3 years; range 18–64 years) initially treated with non-insulin glucose-lowering agents (GLAs) in 2008–2016. Based on clinical guidelines, we identified early (N = 1,158; 6%; insulin initiation ≤ 6 months after first-line GLAs), in-time (N = 569; 3%; 6–12 months), delayed (N = 2,761; 15%; >12 months), and non-insulin users (N = 13,385; 75%). The Prentice-Williams-Peterson (PWP) models with inverse probability weighting estimated CVD risk across the four groups and the change in risk after insulin initiation. RESULTS: Regardless of time to insulin initiation, insulin users had higher CVD risks after first-line GLAs than non-insulin users (aHR: early: 2.0 [1.5–2.5], in-time: 1.8 [1.2–2.6], delayed: 1.9 [1.6–2.3]). However, we found only a borderline increase in CVD risk after insulin initiation vs. before in early (aHR: 1.4 [1.1–1.8]) and delayed users (aHR: 1.3 [1.0–1.7]), and no increase in in-time users (aHR: 1.3 [0.9–2.0]). CONCLUSIONS: We observed no gains in CVD benefits from insulin initiation in the early stages of pharmacotherapy possibly because CVD developed before insulin initiation. Additional management of hypertension and dyslipidemia may be important to reduce CVD risk in this young and middle-aged T2D cohort.