Emergency department use by primary care patients at a safety-net hospital.

beneficiaries was $6832, but expenditures were significantly less for overweight and obese beneficiaries ($5473 [P .001] and $5790 [P=.02], respectively). Expenditures increased over time for all groups but appeared to increase more quickly in obese beneficiaries. In regression analysis adjusting for demographic and economic covariates, expenditures increased by a mean of $122 per year (P .001) for normal-weight beneficiaries, and increased significantly faster for overweight (excess increase of $108 per year [P=.01]) and obese beneficiaries (excess increase of $149 per year [P=.001]). Adjusting for chronic conditions accounted for differences in the trend across BMI groups. After adjusting for chronic conditions, interactions between overweight and time (P=.71) and obesity and time (P=.98) were no longer significant.