Older and sicker--and happier in an HMO.
D000368:Aged; D000369:Aged, 80 and over; D001294:Attitude to Health; D003625:Data Collection; D006279:Health Maintenance Organizations / Q000592:standards*; D006801:Humans; D006278:Medicare / Q000592:standards* / Q000706:statistics & numerical data; D017060:Patient Satisfaction / Q000706:statistics & numerical data*; D014481:United States