Readmissions and adverse drug reactions in internal medicine: the economic impact

Abstract. Dormann H, Neubert A, Criegee-Rieck M,Egger T, Radespiel-Tro¨ger M, Azaz-Livshits T, LevyM, Brune K, Hahn EG (University of Erlangen-Nuremberg, Germany; and Hadassah-HebrewUniversity Medical Center, Jerusalem, Israel)Readmissions and adverse drug reactions ininternal medicine: the economic impact. J InternMed 2004; 255: 653–663.Background. Recent studies show that nearly halfof the hospitalized patients are readmitted within6 months from discharge. No data exist about therelationship between adverse drug reactions (ADRs)and readmittance to a department of internalmedicine.Objectives. The primary aims of the study were todetermine if ADRs could be used as predictors forrecurrent hospitalizations in internal medicine andto evaluate the economic impact of ADRs onhospitalization costs.Design and setting. A cohort-based, prospective,18-month pharmacoepidemiological survey wasconducted in the Department I of InternalMedicine at the University Hospital of Erlangen. Allpatients were intensively monitored for ADRs by apharmacoepidemiological team. ADRs wereevaluated for their offending drugs, probability,severity, preventability and classified by WHO-ART. During a 6-month period ADR-positivepatients were matched to non-ADR patientsapplying diagnosis-related group categorization inorder to measure the impact of ADRs on theduration and frequency of hospitalization.Results. Of 1000 admissions 424 patients hadsingle admissions and 206 patients had recurrentreadmissions (min 1, max 9). The prevalence ofreadmissions was 37% (n ¼ 370). In 145 (23%) of630 patients, 305 ADRs were observed. The ADRincidence was similar in first admissions andreadmissions. ADRs were not found to predictfurther readmissions and lack of ADRs did notpreclude readmissions. ADRs caused hospitalizationsin 6.2% of first admissions and in 4.2% ofreadmissions. According to the Schumockalgorithm 135 (44.3%) ADRs were found to bepreventable. The occurrence and numbers of ADRsper admission were found to prolong hospitalizationperiod significantly (r ¼ 0.48 and 0.51, P 973 days) of all treatment days were judgedto be preventable.Conclusions. Intensified drug monitoring supportedby information technology in internal medicine isessential for early detecting and prevention of ADRsand saving hospital resources.Keywords: adverse drug reaction, hospitalreadmission, information technology, pharmaco-vigilance, quality of care, resource utilization.