Fig 4. Association between equivalent income and duration of outpatient care.

Adjusted means and 95% CIs are shown. The number of subjects who received outpatient care services in the survey year was 180,256. The duration of outpatient care was predicted by the GEE with a Poisson distribution and log function considering the correlation within household. This model has main associations (age, sex, and equivalent income), two-way interactions (age*sex, age*equivalent income, sex*equivalent income), three-way interaction (age*sex*equivalent income), and two covariates (the number of family members and residence).