Increased ambulatory care copayments and hospitalizations among the elderly.

BACKGROUND When copayments for ambulatory care are increased, elderly patients may forgo important outpatient care, leading to increased use of hospital care. METHODS We compared longitudinal changes in the use of outpatient and inpatient care between enrollees in Medicare plans that increased copayments for ambulatory care and enrollees in matched control plans--similar plans that made no changes in these copayments. The study population included 899,060 beneficiaries enrolled in 36 Medicare plans during the period from 2001 through 2006. RESULTS In plans that increased copayments for ambulatory care, mean copayments nearly doubled for both primary care ($7.38 to $14.38) and specialty care ($12.66 to $22.05). In control plans, mean copayments for primary care and specialty care remained unchanged at $8.33 and $11.38, respectively. In the year after the rise in copayments, plans that increased cost sharing had 19.8 fewer annual outpatient visits per 100 enrollees (95% confidence interval [CI], 16.6 to 23.1), 2.2 additional annual hospital admissions per 100 enrollees (95% CI, 1.8 to 2.6), 13.4 more annual inpatient days per 100 enrollees (95% CI, 10.2 to 16.6), and an increase of 0.7 percentage points in the proportion of enrollees who were hospitalized (95% CI, 0.51 to 0.95), as compared with concurrent trends in control plans. These estimates were consistent among a cohort of continuously enrolled beneficiaries. The effects of increases in copayments for ambulatory care were magnified among enrollees living in areas of lower income and education and among enrollees who had hypertension, diabetes, or a history of myocardial infarction. CONCLUSIONS Raising cost sharing for ambulatory care among elderly patients may have adverse health consequences and may increase total spending on health care.