Effect of High-Deductible Insurance on High-Acuity Outcomes in Diabetes: A Natural Experiment for Translation in...

High-deductible health plans (HDHPs) are now the predominant commercial health insurance benefit in the U.S. We sought to determine the effects of HDHPs on emergency department and hospital care, adverse outcomes, and total health care expenditures among patients with diabetes.

We applied a controlled interrupted time-series design to study 23,493 HDHP members with diabetes, aged 12-64, insured through a large national health insurer from 2003 to 2012. HDHP members were enrolled for 1 year in a low-deductible (≤$500) plan, followed by 1 year in an HDHP (≥$1,000 deductible) after an employer-mandated switch. Patients transitioning to HDHPs were matched to 192,842 contemporaneous patients whose employers offered only low-deductible coverage. HDHP members from low-income neighborhoods (n = 8,453) were a subgroup of interest. Utilization measures included emergency department visits, hospitalizations, and total (health plan plus member out-of-pocket) health care expenditures. Proxy health outcome measures comprised high-severity emergency department visit expenditures and high-severity hospitalization days.

After the HDHP transition, emergency department visits declined by 4.0% (95% CI -7.8, -0.1), hospitalizations fell by 5.6% (-10.8, -0.5), direct (nonemergency department-based) hospitalizations declined by 11.1% (-16.6, -5.6), and total health care expenditures dropped by 3.8% (-4.3, -3.4). Adverse outcomes did not change in the overall HDHP cohort, but members from low-income neighborhoods experienced 23.5% higher (18.3, 28.7) high-severity emergency department visit expenditures and 27.4% higher (15.5, 39.2) high-severity hospitalization days.

After an HDHP switch, direct hospitalizations declined by 11.1% among patients with diabetes, likely driving 3.8% lower total health care expenditures. Proxy adverse outcomes were unchanged in the overall HDHP population with diabetes, but members from low-income neighborhoods experienced large, concerning increases in high-severity emergency department visit expenditures and hospitalization days.