Interações medicamentosas em pacientes hospitalizados: exposição, relação com indicadores de internação e intervenção

Abstract

Introduction: Drug-drug interactions (DDI) are an important health problem as they can lead to adverse events, including adverse drug reactions. Risk of occurrence is associated with several factors, among them the number of drugs prescribed and patients age. Objectives: To verify the frequency of potential drug-drug interactions in hospital settings and to identify the associated factors for these; to assess the association between DDIs and hospital outcomes and to evaluate the impact of prospective DDIs screening system coupled with pharmaceutical intervention on decreasing the frequency of drug interactions. Methods: Prescriptions of adult patients admitted to the Hospital Geral de Vitória da Conquista, Bahia, were evaluated for drug interactions in a retrospective study covering one-year period (2007). Results of this baseline study, when DDIs screening system was not provided, were compared with those from a prospective four-month study (20092010) to assess differences in the frequency of drug interactions. Additionally, factors associated with DDIs and the influence of these on length of hospital and Intensive Care Unit (ICU) stays, mortality and readmission were also investigated in the baseline study. Results: A total of 7.480 drug-drug interactions were found in both phases of the study resulting in an average of 3,2 events per admission and 40 events per 100 prescriptions. Having a DDI screening coupled with pharmaceutical intervention resulted in statistically significant decrease in the incidence of DDI. The incidence density rate ratio (measured by Poisson regression) was 0,47, meaning that the presence of intervention decreased potential DDI rate in 53%. According to the multiple Cox regression, DDI was associated with prolonged length of hospital stay and length of ICU stay in the baseline period. Multiple logistic regression also indicated that drug interaction was significantly associated with higher odds of readmission and inpatient mortality rates were similar for those with and without drug interaction. Conclusion: Patients are submitted to high risk of potential drug interactions in hospital and they should be continuously monitored to identify such events. A screening software coupled with pharmaceutical intervention produced a significantly reduction in DDI frequency. This approach can yield many benefits and represents an important issue for patient safety.