Determinants of Non-adherence to Long Term Therapy With Prescription Medicines in Adult Patients Attending Medical Outpatient Clinic at Mbagathi Hospital

Abstract

Background Non-adherence is a drug therapy problem and can be due to economic factors, patient related factors among others. Studies have shown that non-adherence to prescribed medicines in general is as high as 20% to 60% irrespective of disease, setting or prognosis. This study is informed by there being minimal data on non-adherence among the study population in Kenya and Sub Saharan Africa in general. Study objective The aim of the study was to determine the magnitude and to identify the determinants of non-adherence to long term prescription medicines among adult outpatients attending medical outpatient clinic at Mbagathi Hospital. Methodology The study was hospital based, descriptive cross-sectional study to establish factors associated with non-adherence to prescribed medication for those patients attending the medical outpatient clinic of Mbagathi Hospital and on long term therapy. The study population was adult patients, on follow up. Data was collected over a period of one month. An adjusted sample size of 167 patients was used. Convenient sampling method was used to consecutively select every accessible patient who met the inclusion criteria. Data was collected using pretested questionnaires. Data collected was entered in a modified excel sheet and STATA version 13 used for analysis. Continuous variables were summarized to measures of central tendency. Categorical variables were summarized as percentages. Data was presented in the form of graphs, pie charts and tables. Inferential data analysis was carried out to look for association between the outcome variable (non-adherence to long term medicines) and the predictor variables for example patient related causes of non-adherence. Bivariate and multivariate logistic regression (backward stepwise) was done to identify the independent predictors of non-adherence to long term prescription medicines. Results A total of 167 respondents participated in the study with a mean age of 53.5±13.5 years. Majority were of the female gender (101, 60.5%).Overall, a third (57, 34.1%) of the participants were non-adherent to their long term therapy while 110 (64.9%) were adherent. Hypertension was the most prevalent (127, 76.1%) condition in the study population. Bivariate analysis showed statistically significant associations between non-adherence and patient understanding their disease(p=0.001),being aware of the need to take their drugs daily (p=<0.001),understanding dosage instructions (p=0.018),forgetting to take drugs, careless about taking their drugs, stopping to take after feeling better or worse all with (p=<0.001).Awareness of the need to take drugs daily was an independent predictor of non-adherence as indicated by bivariate analysis (COR =0.07; 95% CI 0.02-0.2; p<0.001) and on multivariate regression analysis (AOR=0.13; 95% CI 0.3-0.54 p=0.005),being bothered by the duration of treatment (COR = 2.13; 95% CI 1.1-4.11; p=0.024) together with patient understanding dosage instructions (COR=0.25; 95% CI 0.08-0.8;p=0.019). Headache as a side effect was an independent predictor of non-adherence as indicated by bivariate analysis (COR =5.31; 95% 2.5-11.3; p<0.001) and this prediction further affirmed on multivariate logistic regression (AOR=5.48; 95% CI 1.61-18.6 p=0.006). Conclusion Non adherence as a drug therapy problem is predominant on patients on long term therapy. This non adherence can in effect result to treatment failure and a bad medication experience and therefore there is an immediate need to curb this in our outpatient set ups.