Avoidable hospitalizations due to adverse drug reactions in an acute geriatric unit. Analysis of 3,292 patients

To determine prevalence of admissions due to an adverse drug reaction (ADR) and determine whether or not admission was avoidable, and what drugs and risk factors were implicated.

Cross-sectional observational study.

All patients hospitalized in an acute geriatric unit during the period January 2001 to December 2010 were studied.

To determine whether admissions were due toADR, we used the World Health Organization-Uppsala Monitoring Centre criteria and the Naranjo scale. Beers criteria were used to detect potentially inappropriate medication.

A total of 3,292 patients (mean age 84.7 years, 60.1% women) were studied. Of these, 197 (6%) were admissions for ADR and nearly three quarters (76.4%, 152 cases) were considered avoidable admissions. The 5 most frequent drugs associated with admissions for ADR were digoxin, nonsteroidal anti-inflammatory drugs, benzodiazepines, diuretics and antibiotics. Independent risk factors for admissions for ADR were being female (OR 1.84; 95% CI 1.30-2.61), inappropriate medication according to Beers criteria (OR 4.20; 95% CI 2.90-6.03), polypharmacy (>5 drugs) (OR 1.50; 95% CI 1.04-2.13), glomerular filtration rate<30mL/min (OR 3; 95% CI 2.12-4.23) and sedative use (OR 1.40; 95% CI 1-1.91).

ADR were responsible for 6% of admissions to an acute geriatric unit, and over 75% of these admissions were considered avoidable. Associated risk factors were being female, inappropriate medication, polypharmacy, renal insufficiency and sedative use.