Abstract and Introduction
Abstract
Objective: To use the natural experiment of health insurance reform in Massachusetts to study the impact of increased insurance coverage on ICU utilization and mortality.
Design: Population-based cohort study.
Setting: Massachusetts and four states (New York, Washington, Nebraska, and North Carolina) that did not enact reform.
Patients: All nonpregnant nonelderly adults (age 18–64 yr) admitted to nonfederal acute care hospitals in one of the five states of interest were eligible, excluding patients who were not residents of a respective state at the time of admission.
Measurements: We used a difference-in-differences approach to compare trends in ICU admissions and outcomes of in-hospital mortality and discharge destination for ICU patients.
Main Result: Healthcare reform in Massachusetts was associated with a decrease in ICU patients without insurance from 9.3% to 5.1%. There were no significant changes in adjusted ICU admission rates, mortality, or discharge destination. In a sensitivity analysis excluding a state that enacted Medicaid reform prior to the study period, our difference-in-differences analysis demonstrated a significant increase in mortality of 0.38% per year (95% CI, 0.12–0.64%) in Massachusetts, attributable to a greater per-year decrease in mortality postreform in comparison states (–0.37%; 95% CI, –0.52% to –0.21%) compared with Massachusetts (0.01%; 95% CI, –0.20% to 0.11%).
Conclusion: Massachusetts healthcare reform increased the number of ICU patients with insurance but was not associated with significant changes in ICU use or discharge destination among ICU patients. Reform was also not associated with changed in-hospital mortality for ICU patients; however, this association was dependent on the comparison states chosen in the analysis.
Introduction
Lack of health insurance is associated with preventable morbidity and mortality in acute care, particularly among patients with critical illness. Although expanding health insurance coverage may improve overall health,it may also lead to increases in healthcare use and costs and further exacerbate existing inefficiencies in the healthcare system. ICU utilization and costs in the United States are already high relative to other nations, and although ICU care is not the sole driver of rising healthcare costs, curbing ICU costs through more efficient use is considered a key component of reducing overall healthcare spending. The degree to which efforts to broaden access to health insurance increase ICU use and improve outcomes for those that experience critical illness remains unknown.
Information on the impact of changes in health insurance status is particularly important, given the passage of the Patient Protection and Affordable Care Act (ACA), which expands access to health insurance through several provisions modeled after the health insurance reform enacted by Massachusetts in July 2006. Massachusetts health insurance reform required all adults to purchase health insurance by July 1, 2007. Within 3 years, over 430,000 Massachusetts residents were enrolled in health insurance programs, reducing the percentage of uninsured residents in Massachusetts from approximately 10.9% to less than 6.3%.
We sought to use the Massachusetts experience to anticipate the impact of the ACA on critical care use and outcomes in the United States. Prior studies of insurance expansion demonstrate increased outpatient and inpatient access to health services and decreased mortality. Greater access not only increases an individual's opportunity to seek elective procedures that require ICU care but also allows for better preventive care, which may reduce the burden of comorbid illness and ultimately an individual's risk of death in the ICU. Individuals with insurance are also more likely to present earlier in the course of their illness when their acute illness severity is lower. These are only a few of the ways that gaining insurance may impact ICU use and reduce mortality. As such, we hypothesized that insurance reform would be associated with increased ICU use and reduced mortality among the critically ill. Additionally, because insurance status is associated with differences in hospital discharge practice among the critically ill, we also examined the impact of insurance reform on hospital discharge location among ICU survivors in Massachusetts. Some of these results have been previously reported in the form of abstracts.