Development and validation of a clinical instrument to predict risk of an adverse drug reactions in hospitalized patients.

Objective: Development and internal validation of a clinical tool for assessment of the risk of adverse drug reactions (ADR) in hospitalized patients.

Methodology: Nested case-control study in an open cohort of all patients admitted to a general hospital. Cases of ADR were matched to two controls. Eighty four patient variables collected at the time of the ADR were analyzed by conditional logistic regression. Multivariate logistic regression with clustering of cases in a random sample of 2/3 of the cases and respective controls, with baseline odds-ratio corrected with an estimate of ADR incidence, was used to obtain regression coefficients for each risk factor and to develop a risk score. The clinical tool was validated in the remaining 1/3 observations. The study was approved by the institution's research ethics committee.

Results: In the 8060 hospitalized patients, ADR occurred in 343 (5.31%), who were matched to 686 controls. Fourteen variables were identified as independent risk factors of ADR: female, past history of ADR, heart rate ≥72 bpm, systolic blood pressure≥148 mmHg, diastolic blood pressure <79 mmHg, diabetes mellitus, serum urea ≥ 67 mg/dL, serum sodium ≥141 mmol/L, serum potassium ≥4.9 mmol/L, main diagnosis of neoplasia, prescription of ≥3 ATC class B drugs, prescription of ATC class R drugs, prescription of intravenous drugs and ≥ 6 oral drugs. In the validation sample, the ADR risk tool based on those variables showed sensitivity 61%, specificity 73% and area under the ROC curve 0.73.

Conclusion: We report a clinical tool for ADR risk stratification in patients hospitalized in general wards based on 14 variables.