Nonemergency emergency room use in patients with and without primary care physicians.
D000328:Adult; D004630:Emergencies; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D008297:Male; D008824:Michigan; D010548:Personal Health Services / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012907:Smoking