Is age an independent risk factor of adverse drug reactions in hospitalized medical patients?

OBJECTIVE

To study the incidence and the risk factors of adverse drug reactions.

DESIGN

Multicenter survey.

SETTING

Hospitalized care: 22 internal medicine and 19 geriatric wards.

PATIENTS

All patients (n = 9,148) consecutively admitted during two observation periods of 2 months.

MAIN OUTCOME MEASURE

Incidence of adverse drug reactions.

RESULTS

The mean age was 67.1 +/- 0.17 years (median 72); the mean duration of hospital stay was 18.1 +/- 0.19 days (median 14). Each patient was administered 5.1 +/- 0.03 (median 5) drug prescriptions. The incidence of probable or definite adverse drug reactions was 5.8% (532/9,148). In univariate analysis, the incidence of adverse drug reactions increased from 3.3% at under age 50 to 6.5% at age 70-79 and decreased over age 80 (5.8%). In multivariate logistic regression, taking more than four drugs (OR = 2.94, CI = 2.38-3.62), staying in hospital more than 14 days (OR = 2.82, CI = 2.26-3.52), having more than 4 active medical problems (OR = 1.78, CI = 1.29-2.45), staying in a medical ward instead of geriatric ward (OR = 1.33, CI = 1.09-1.63), and drinking alcohol (OR = 1.28, CI = 1.03-1.58) were positively correlated with adverse drug reactions occurrence (P less than 0.05). Age, gender, and smoking cigarettes were not significant predictors of adverse drug reactions.

CONCLUSION

Age is not an independent risk factor of adverse drug reactions, and good geriatric care can reduce the incidence of adverse drug reactions.