IDENTIFYING DIABETES-MELLITUS OR HEART-DISEASE AMONG HEALTH MAINTENANCE ORGANIZATION MEMBERS - SENSITIVITY, SPECIFICITY, PREDICTIVE VALUE, AND COST OF SURVEY AND DATABASE METHODS

We conducted a study of the sensitivity, specificity, positive predict ive value, and cost of two methods of identifying diagnosed diabetes m ellitus or heart disease among members of a health maintenance organiz ation (HMO). Among 3186 adult HMO members who were attending one prima ry cave clinic, 2326 were reached for a telephone survey (efficiency = 0.73). Among these members, 1991 answered standardized questions to a scertain whether they had diabetes or heart disease (corrected respons e rate 0.85). Linkage was then made to computerized diagnostic databas es. By means of both a database method and a survey method, the 1976 m embers with complete data for analysis were classified as having or no t having diabetes or heart disease. When results with the two methods disagreed, charts were reviewed to confirm the presence or absence of diabetes or heart disease. Diabetes was identified among 4.7% of adult members, and heart disease was identified among 3.7%. Identification of diabetes differed between the database method and the survey method (sensitivity 0.91 vs 0.98, specificity 0.99 vs 0.99, positive predict ive value 0.94 vs 0.83). Identification of heart attack history was si milar for the database method and the survey method (sensitivity 0.89 vs 0.95, specificity 0.99 vs 0.99, positive predictive value 0.79 vs 0 .81). The cost of obtaining data was $13.50 per member for the survey method and $0.30 per member for the database method. Database methods or survey methods of identifying selected chronic diseases among HMO m embers may be acceptable for various purposes, but database identifica tion methods appear to be less expensive and provide information on a higher proportion of HMO members than do survey methods. Accurate iden tification of chronic diseases among patients supports clinic-level me asures for clinical improvement, research, and accountability.