Consumo inadequado de medicamentos entre idosos em Montes Claros, Minas Gerais

Abstract

The purpose of this survey is to investigate the prevalence of inappropriate drug use and its associated factors in community dwelling elderly. We conducted in home interviews with 165 subjects aged 60 years and older, living in the community of one neighborhood of Montes Claros, Brazil (population 306.0000 approximately). Trained interviewers visited all clients at home. Subjects were asked to report all use of prescription drugs and over-thecounter medications. In addition the interviewers collected information on health and health care use, as well as data on the social demographics, education, income, number of chronic conditions, retirement, occupation and general perception on one's own health. Inappropriate medication use was evaluated using explicit criteria developed through a Delphi consensus process by BEERS et al (1991). This criteria identifies drugs that should generally be avoided in elderly use in nursing homes subjects regardless of clinical circumstances. It uses, basically, three concepts: prescription medicines that should be entirely avoided in the elderly, excessive dosage, and excessive duration of treatment. The units of analysis on all computations were the individual subject and the drug consumption. At first there was a distribution of frequency on the different variables analyzed in order to evaluate the general characteristics of the subjects. The use of inappropriate drugs was the independent variable. To identify the associated factors of using inappropriate drugs, the subjects were compared in two groups of appropriate and inappropriate users of drugs in relation to one specific factor at a time. To verify the odds between the associated factors and the use of inappropriate drugs was utilized the odds ratio on a 95% interval (confidence limit). The statistic significance of the differences was detected using the chi-square on a level of p < 0,05. The survey was answered by 90,3% solely and 9,7% had a companion to help. The age of the elderly varied from 60 to 94 with an average of 69 years of age. The age class between 60 and 74 years counted 77%. There were 57,ó% women. There were 58,2% married, 31,5% widowed and 10,3% single or separated. There were 67,3% that had an income of one minimum salary. Most of the elderly were illiterate with 65,5% and 34,5% informed that they knew how to read and write. The elders mentioned their problems in order of most frequent as being: high blood pressure, diabetes, "rheumatism", generic pain and changes in humor. According to the standard of medicine consumption, out of the 165 elders, only 9,7% did not use any medication and 90,3% consumed at least one prescribed medication (81,8%) or over-the-counter drugs (8,5%). The average medicine use is 3,8 drugs per patient. Over a quarter of the subjects used four or more medications (polypharmacy). There were 33 therapeutical classes and 45 pharmaceutical substances which could not be classified because they didn't follow model list of essential drugs (1999). On the class of the patients who used prescribed medicines, 68,9 % of them were inadequate. The inadequate drugs prescribed were the antihypertensives and sedative-hypnotics. There weren't any statistic association between the inadequate prescribed drugs and some variables (age, gender, marital status, school education, income, self perception of health and memory, number of office visits, hospital admissions). On the other hand, the elderly people who use more than 3 medicines are 4,26 times more likely to be taking at least one inadequate drug (OR=4,26; 1,41 -13,82). The polypharmacy (4 or more medications) is also associated with the self referred illnesses. The elder who self referred more than 3 illnesses is 4 times more likely to be taking more than 3 medicines (OR=3,87; 1,68-9.04) and 6 times more likely if he referred 4 illnesses (OR=6,00; 1,99-19,37). This results demonstrated an important progressive association. The older people who dispense medicine on the public pharmacy unit is 7 times more likely to be getting some inappropriate drug than the ones who buy it on the private pharmacy (OR=6,57; 2,70-16,01). The polypharmacy is associated with the negative self health perception too. The ones who have a negative self perception are 3,34 times more likely to use more than 3 medicines (OR=3,34;

1,49-7,61). This study provides representative data of medication usage among older people in Montes Claros - Brazil. The prevalence of inappropriate prescribed drug use was very high. That might demonstrate that the physicians lack knowledge about the differences of pharmacokinetics and pharmacodynamics applied to the elderly people. Another hypothesis is that the public health system doesn't offer appropriate drugs for the older people. As there aren't the appropriate drugs on the public pharmacy, the tendency is that the medical doctor will prescribe the medicines available, even when they aren't the safest.