Congestive heart failure incidence and prognosis: case identification using central adjudication versus hospital discharge diagnoses.

PURPOSE: We compared hospitalized congestive heart failure (CHF) incidence and prognosis estimates using hospital discharge diagnoses or central adjudication.
METHODS: We used the Cardiovascular Health Study (CHS), a population-based cohort study of 5888 elderly adults. A physician committee adjudicated potential CHF events, confirmed by signs, symptoms, clinical tests, and/or medical therapy. A CHF discharge diagnosis included any of these ICD-9 codes in any position: 428, 425, 398.91, 402.01, 402.11, 402.91, and 997.1. We constructed an inception cohort of 1209 hospitalized, nonfatal, incident CHF cases, identified by discharge diagnosis, adjudication, or both.
RESULTS: Incidence rates for hospitalized CHF were 24.6 per 1000 person-years using discharge diagnoses and 17.1 per 1000 person-years using central adjudication. Compared to the group identified as having CHF by both methods, the group with only a discharge diagnosis (hazard ratio=0.77, 95% confidence interval=0.65-0.91) and the group with central adjudication only (hazard ratio=0.72, 95% confidence interval=0.55-0.94) had lower mortality rates.
CONCLUSIONS: In the elderly, studies using only discharge diagnoses, as compared to central adjudication, may estimate higher rates of incident hospitalized CHF. Mortality following CHF onset may be similar for these methods and higher if both methods are used together.