Medicare + Choice.
D005260:Female; D006801:Humans; D008297:Male; D008329:Managed Care Programs / Q000191:economics / Q000458:organization & administration*; D006278:Medicare / Q000191:economics / Q000331:legislation & jurisprudence / Q000458:organization & administration*; D008824:Michigan; D010818:Practice Patterns, Physicians'; D014481:United States