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Are Prescription Drugs and Preventive Health Behavior Substitites? Evidence from Medicare Part D
Using the National Health Interview Survey and Medical Expenditure Panel Survey, I examine whether prescription drug use substitutes investment in preventive health behaviors. To identify their causal relationship, I estimate the differences in the regression discontinuity of prescription drug uses and preventive health behavior at age 65 before and after the implementation of Medicare Part D. The resulting estimates indicate that the implementation of Medicare Part D increases prescription drug insurance coverage and prescription drug use. This led to a 10 percentage point reduction in the probability of engaging in moderate physical activity at the extensive margin, a 6.47% reduction in the probability of having healthy-weight and a 9.56 percentage point increases in the probability of being overweight. The effects on moderate physical activity at the intensive margin, vigorous strength physical activity--both at the intensive and extensive margin--cigarette smoking, body mass index and obesity are not statistically significant. The physical exercise, healthy-weight and overweight effect of prescription drug use is stronger among sub-group of individuals that experienced greater prescription drug coverage gain due to Medicare Part D .
Key Words: Prescription Drug, Preventive Health Behavior, Medicare Part D, Regression Discontinuity