Factors associated with potentially inappropriate medication use by the elderly in the Brazilian primary care setting.

Background: The exposure of elderly patients to potentially inappropriate medication (PIM) is associated with the increased use of health care services.

Objective: To evaluate both the prevalence of and the factors associated with the use of PIM by elderly patients who are being treated in primary healthcare facilities.

Setting: Family Health Programme centres in northeastern Brazil.

Method: A prospective survey of the medications used by elderly patients was performed. A total of 142 participants were randomly selected via systematic sampling. Beers criteria were applied to assess the use of PIM among the investigated sample. All of the medications included in these criteria were assessed for their availability in Brazil. The prevalence of inappropriate medications was chosen as an occurrence measure and was compared among the exposure groups using the prevalence ratio (PR) as a measure of association.

Main Outcome Measure: Prevalence and various factors associated with the use of PIM. Results The prevalence of PIM usage was 34.5 %. The factors that exhibited associations included the following: illiteracy (PR = 1.51; 95 % CI = 1.02-2.24); black skin colour (PR = 1.80; 95 % CI = 1.40-2.32); the use of ≥4 drugs per day (PR = 2.36; 95 % CI = 1.79-3.11); the use of medications prescribed by a doctor (PR = 2.52; 95 % CI = 1.12-5.69), and the use of medications supplied by the Brazilian government (PR = 1.42; 95 % CI = 1.10-1.81). The most frequently prescribed PIM included short-acting nifedipine (34.5 %) and methyldopa (9.1 %).

Conclusion: The data collected in this study indicated a high prevalence of the use of PIM. The factors that contributed the most to this prevalence included medical prescriptions, polypharmacy, medications supplied by the Brazilian National Health System, and black skin colour (specifically, being of African descent).