Medical costs of cigarette smoking in a health maintenance organization.

This study involved direct observation of the differences in utilization of medical care by smokers, nonsmokers, and former smokers. A household interview survey conducted in 1970-1971 obtained detailed information about the smoking patterns of 2,582 adult members of the Northwest Kaiser Permanente health maintenance organization in metropolitan Portland, Oregon. These data were linked to computerized medical records which documented all inpatient and outpatient care for 1967-1974. Current smokers used 20% more hospital days/1,000 person-years (adjusted for age, sex, alcohol intake, duration of observation) than did never smokers. Former smokers, but not smokers, used more outpatient services than did nonsmokers. Among smokers, there was no detectable relationship between use of medical care services and number of cigarettes smoked per day.