Case-mix adjustments for patient reported experience and outcome measures in primary care: an empirical approach to identify patient characteristics as case-mix adjusters based on a secondary analysis of an international survey among patients and their general practitioners in 34 countries

Journal of Patient-Reported Outcomes

Table 2 Summary of the analyses for the dependent variable Access (PREM), multilevel linear regression

Potential case-mix variable	Fixed effect significant (y/n)	Slope effect GP level important* (y/n)	Slope effect Country level important (y/n)	Case-mix control (y/n)
Self-reported general health	Yes Worse self-reported health → worse experienced access	No	No	Yes
Longstanding disease	No	No	No	No
Patient’s age	Yes Older than 40 → better experienced access	No	No	Yes
Patient’s sex	No	No	No	No
Education	Yes Higher education → better experienced access	No	No	Yes
Income	Yes Higher income → better experienced access	No	No	Yes
Migrant status	Yes Migrant status → lower experienced access	No	No	Yes
Place of living	Yes Outside big cities → better experienced access	Yes	No	No Importantly more variation big (inner) cities compared to rural areas

^*Important means that the difference in variance between categories is more that 0.25*variance in the model with fixed effect and random intercept