INCIDENCE OF HOSPITALIZATION FOR DIGITALIS TOXICITY AMONG ELDERLY AMERICANS

OBJECTIVE: To document the prevalence of digitalis use and the inciden ce of hospitalization caused by digitalis toxicity. DESIGN: Observatio nal cohort followed for 6 years. SETTING: Urban community. PARTICIPANT S: Persons were eligible if they were (1) enrolled in the Yale Health and Aging Project and (2) using digitalis when interviewed in 1982 or 1985. The Project comprises a sample of noninstitutionalized persons a ged 65 years and over living in New Haven, Connecticut. METHODS: Betwe en 1982 and 1988 when a Project participant was hospitalized in New Ha ven, a researcher reviewed the medical record and coded up to 16 Inter national Classification of Diseases-Class 9 (ICD-9) diagnoses. To iden tify hospitalizations caused by digitalis, we reexamined records with ICD-9 codes suggesting toxicity. We confirmed the admission illness wa s an adverse drug reaction with a decision algorithm. RESULTS: The pre valence of digitalis use was 13% in 1982 and 12% in 1985. The incidenc e of hospitalization caused by definite or probable toxicity was 4.2% (95% confidence interval = 0.3% to 8.1%) over 6 years. Manifestations of toxicity were malaise or gastrointestinal symptoms (two patients) a nd heart block plus malaise or gastrointestinal symptoms (six patients ). Use of quinidine was associated (p<.05) with toxicity. CONCLUSION: Knowledge about the incidence of severe, morbid toxicity may help clin icians estimate and compare the risks and benefits of digitalis and al ternate therapies.