ASSOCIATION BETWEEN POSTDISCHARGE ADVERSE DRUG REACTIONS AND 30-DAY HOSPITAL READMISSION IN PATIENTS AGED 80 AND OLDER

Abstract

To the Editor: Nearly one-fifth of Medicare patients are rehospitalized within 30 days of discharge.1 In July 2008, the National Quality Forum adopted hospital performance measures based on the rate of hospital readmission. The Centers for Medicare and Medicaid Services (CMS) has identified several diagnoses for which 30-day readmission rates will influence future value-based hospital payments. Reduction in potentially preventable readmission is thus an important focus of current quality improvement research. Adverse drug reactions (ADRs) are a well-known cause of hospital admission in all age groups. The World Health Organization defines an ADR as “any response to a drug which is noxious and unintended, and which occurs at doses normally used in man for prophylaxis, diagnosis or therapy of disease, or for the modification of physiological function.”2 In the general population, approximately 5.3% of hospital admissions are associated with ADRs.3 ADRs are even more common in older adults; a recent population-based cohort study in older adults showed that 17.7% of patients had a repeat admission for an ADR,4 but the currently available literature is limited because it has not covered 30-day readmissions in the oldest patients (≥80), who are at the highest risk for ADRs. The study's goal was to evaluate the association between ADRs and subsequent hospital readmission in adults aged 80 and older. This institutional review board–approved retrospective observational study was conducted at a tertiary care, university-affiliated teaching hospital in Kansas City, Missouri. A retrospective review of electronic patient charts from January 1, 2008, through December 31, 2008, was performed for persons aged 80 and older who were readmitted within 30 days of previous discharge, excluding planned readmissions. ADRs were identified at the time of readmission using the stated reasons for readmission in the physicians' history and physical and discharge summary documentation. An ADR was also considered to be present if clinical symptoms or signs described in the chart were associated with the discontinuation or dosage change of a medication thought to have caused that clinical finding. For example, if a patient taking an antiplatelet drug presented with gastrointestinal bleeding, and the drug was subsequently discontinued, this was deemed an ADR. Of 282 persons with 30-day readmissions, 66 (23.4%) had an ADR that contributed to rehospitalization. The mean age was 86.8; 35% were male, and 65% were female. The average length of stay was 4.7 days. The most commonly implicated medication classes were anticoagulants and antiplatelet agents (36%), diuretics and antihypertensives (32%), and opioids (14%). The most common adverse event was bleeding (33%). The average number of drugs was 11.7 in persons with an ADR contributing to readmission and 10.9 in persons without a contributory ADR (Table 1). Nearly one-fourth of cases of 30-day readmission had an ADR contribute to the readmission. Limitations include small study size, sampling from a single hospital, and a single data abstractor. Rates of ADRs contributing to rehospitalization are several times as high for the oldest patients (∼23%) than those reported for the general hospitalized population (∼6%).5 Antiplatelet drugs, anticoagulants, and antihypertensive drugs were responsible for nearly 60% of these ADR-related readmissions. Discharge teams and outpatient care providers must collaborate to facilitate scheduling of timely hospital follow-up appointments at which the focus should be on early identification of ADRs, particularly for patients taking these higher-risk medications. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. Author Contributions: All authors contributed equally to study concept and design and analysis and interpretation of data. Dr. Teymoorian was the primary data collector and prepared the manuscript. Sponsor's Role: Not applicable.