Association for Public Policy Analysis & Management

Background: Rising health care expenditures in the United States have led to substantial growth in health insurance premiums. The reduced affordability of health care has become a pressing national concern, and a variety of proposals have been suggested to limit costs and increase access to health care. A prominent strategy for containing health insurance premiums is through increasing demand-side cost-sharing. As a result, the US health insurance markets have experienced a boom of high-deductible health plans (HDHP). Several studies have documented that many HDHP enrollees defer essential medical care and experience diagnostic and treatment delays.

Objective: To test whether enrollment in an HDHP leads to increased risk-adjusted mortality.

Sample: We used data from the Truven Health MarketScan^® Commercial Claims and Encounters database for 2007-2015, a large collection of health care claims compiled from select employer-sponsored health plans across the US. We limited the sample to individuals aged 26-64 years who were enrolled in a health plan for at least 1 year, and we followed each study subject until loss to follow-up or death.

Methods: We implemented a quasi-experimental design based on instrumental variable analysis. We used the first year of each subject’s data to calculate baseline mortality risk scores using the Aggregated Diagnosis Groups obtained from the Johns Hopkins ACG System. Because health plan choices are endogenous, we used an indicator of whether an employer offered a HDHP to its employees in a given calendar year as the instrument to estimate the predicted probability of HDHP enrollment. In the second stage, we estimated the effect of HDHP enrollment on mortality using the Cox proportional hazards model with time-varying instrumented probabilities of HDHP enrollment as the main predictor, adjusted for age, sex, baseline mortality risk, calendar year fixed effects, and employer random effects. Because the outcome (death) may be delayed from the exposure (enrollment in HDHP), we conducted a sensitivity analysis by shifting the outcome by 1, 2, and 3 months to the past.

Results: The sample consisted of 2,001,877 distinct individuals (7,457,890 person-years), 50.8% of which were female. The mean age was 43.2 (SD = 10.8) years. On average, employers offered an HDHP in a given calendar year within the study period to 58.9% of study subjects; however, only 13.5% of study subjects enrolled in an HDHP while the rest chose different health plan types. Over the study period, we observed 3,059 deaths (death rate of 41.0 per 100,000 per year). The second stage Cox regression model revealed a strong effect of HDHP enrollment on risk-adjusted mortality: HR = 1.88 (point estimate = 0.6297, SE = 0.2608, p = 0.016).

Conclusion: Enrollment in an HDHP leads to significantly increased risk of death likely due to diagnostic and treatment delays caused by the substantial financial barrier to care. Abandoning deductibles, however, would lead to substantially increased premiums. Thus, policymakers should develop new cost-sharing mechanisms that better reflect people’s ability to afford health care.