High-deductible insurance: two-year emergency department and hospital use

To determine the 2-year impact of high-deductible health plans (HDHPs) on high-acuity, expensive medical care.

Retrospective pre-post, with propensity score-matched comparison group.

We studied emergency department visits, hospitalizations, and related expenditures among 15,847 HMO members for 1 year before and up to 2 years after an employer-mandated switch to HDHPs, compared with 15,847 propensity-matched controls who remained in HMOs. Members were aged 1 to 64 years and insured between 2001 and 2008.

Emergency department visits among HDHP members declined by 15.0% and 15.7% from baseline to the first and second follow-up years, respectively (95% confidence intervals -21.1% to -8.4% and -24.1% to -6.4%, respectively). Rates of nonemergent visits declined significantly in both years (-19.6% [-28.2% to-9.9%] and -18.1% [-29.8% to -4.4%], respectively), while intermediate-severity visits declined to a lesser degree (-13.4% [-23.0% to -2.5%] in the first and -10.9% [-24.4% to 5.1%] in the second follow-up year). Reductions in emergent visits were not detectable in either the first or second follow-up year (-9.7% [-26.9% to 11.5%] and -15.3% [-36.8% to 13.3%], respectively). Hospitalization rates decreased in the first follow-up year (-22.8% [-33.8% to -10.0%]), but hospitalization and cost reductions were not detectable by the second follow-up year (-11.8% [-27.9% to 7.9%] and 1.9% [-22.2% to 33.4%], respectively).

HDHP members experienced sustained reductions in emergency department visits over 2 years, but reductions in hospital utilization and costs were not apparent by the second year. Longer-term studies that assess deferred utilization and its effects are needed.