Fig. 1

Odds ratios of choosing generic drugs between high- and general-income groups for 311 drugs. Notes: This figure shows odds ratios estimated from the logistic regression Eq. (1) described in the main text for the whole sample including 311 drugs: logistic regression of a binary variable for generic drug dispensed on a 30% co-payment rate (high-income group) dummy adjusting for individual characteristics conducted separately for each drug. Adjusted characteristics include sex, age, prescribed amount, area of patient’s residence, monthly medical expenditure (excluding spending on drugs), and monthly spending on drugs besides the analyzed drug. Each spending is calculated as the sum of spending by the patient and the insurer. Estimated odds ratios for each drug are shown in filled circles. 95% confidence intervals for each drug are shown in horizontal lines. Dotted line shows where odds ratio = 1 holds