Effect of high-deductible insurance on health care use in bipolar disorder.

To determine the impact of high-deductible health plans (HDHPs) on health care use among individuals with bipolar disorder. Interrupted time series with propensity score-matched control group design, using a national health insurer's claims data set with medical, pharmacy, and enrollment data. The intervention group was composed of 2862 members with bipolar disorder who were enrolled for 1 year in a low-deductible (≤$500) plan and then 1 year in an HDHP (≥$1000) after an employer-mandated switch. HDHP members were propensity score matched 1:3 to contemporaneous controls in low-deductible plans. The main outcomes included out-of-pocket spending per health care service, mental health-related outpatient visits (subclassified as visits to nonpsychiatrist mental health providers and to psychiatrists), emergency department (ED) visits, and hospitalizations. Mean pre- to post-index date out-of-pocket spending per visit on all mental health office visits, nonpsychiatrist mental health provider visits, and psychiatrist visits increased by 21.9% (95% CI, 15.1%-28.6%), 33.8% (95% CI, 2.0%-65.5%), and 17.8% (95% CI, 12.2%-23.4%), respectively, among HDHP vs control members. The HDHP group experienced a -4.6% (95% CI, -11.7% to 2.5%) pre- to post change in mental health outpatient visits relative to controls, a -10.9% (95% CI, -20.6% to -1.3%) reduction in nonpsychiatrist mental health provider visits, and unchanged psychiatrist visits. ED visits and hospitalizations were also unchanged. After a mandated switch to HDHPs, members with bipolar disorder experienced an 11% decline in visits to nonpsychiatrist mental health providers but unchanged psychiatrist visits, ED visits, and hospitalizations. HDHPs do not appear to have a "blunt instrument" effect on health care use in bipolar disorder; rather, patients might make trade-offs to preserve important care.