A prevalência de interações medicamentosas em idosos institucionalizados e fatores associados

Abstract

With the increase in life expectancy, chronic diseases and comorbidities become frequent in the elderly, as well as the use of medications and polymedication. The elderly population is a risk group for adverse drug reactions, drug interactions and other adverse events, mainly due to the use of multiple drugs, characterized by polypharmacy. In this sense, the objective was to verify the potential drug interactions with the pharmacological class of antihypertensive drugs and associated factors in prescriptions of institutionalized elderly. A cross-sectional study was conducted from 2017 to 2018, which included 469 individuals aged 60 years and over, residing in 18 Long-Term Care Elderly Institutions (ILPI), who used medicines, and residing in the municipalities of Passo Fundo, Carazinho and Bento Gonçalves, in Rio Grande do Sul - RS. Data were collected through the structured questionnaire interview instrument, and the drugs were previously classified according to Anatomical Therapeutical Chemical (ATC). The prevalence of potential drug-drug interactions was evaluated, and the verification was performed using the Micromedex program. The sociodemographic variables were: age, gender, color / race, marital status, education, type of LSIE and time of residence. The health variables were: heart disease, lung disease, systemic arterial hypertension, diabetes mellitus, stroke, malignant tumor / cancer, insomnia, rheumatism, dementia and chronic pain (in the last 6 months). Descriptive and inferential analysis of the data was performed. To verify the association between categorical variables, Pearson's chi-square and Fisher's exact tests were used at 5% significance level and Poisson regression with robust variance for crude and adjusted analysis. For entry into the multiple model, variables with p <0.20 were considered. Of the study participants, 56.9% belonged to philanthropic ILPI, 57.3% were long-lived, 71.4% were female, 32.4% had lived in ILPI for about 12 to 35 months, 89.5% were white and 73.5% studied around 1 to 8 years. The number of drugs prescribed by the elderly was median of 8, and in relation to drug interactions, the median was 4. Regarding the severity of potential interactions, 77.7% of the elderly had at least one interaction classified as severe, 75.5 moderate, 19.7% lower and 2.5% contraindicated. 67% (n = 314) of the elderly used antihypertensive drugs, and of these 69.7% (n = 219) had drug interactions. In the bivariate analysis the highest prevalence of drug interactions was among the elderly using polypharmacy (56.8%; p <0.001), and in the multivariate analysis the polypharmacy was associated with drug interactions, with the prevalence ratio being 29.3 % (95% CI: 0.191; 0.449). Association with polypharmacy was evidenced in both outcomes, both in bivariate and multivariate analysis. The results of this study contribute to support actions of pharmaceutical assistance in the development of care for institutionalized elderly, and alert health professionals about the rich of polypharmacy and drug interactions.