Self-administration of medications for chronic diseases and drug-related hospital admissions in elderly patients at a Thai hospital

Background Studies of self-administered medications associated with hospital admissions are limited. Objective This study aimed to identify drug-related hospital admissions among elderly patients with diabetes, hypertension and chronic obstructive pulmonary disease and its association with self-administered medications. Method This was a prospective study of 335 patients admitted to a district hospital in Thailand from October 2018 to April 2019. The patients were divided into two groups: one with self-administered medication and the other with caregiver-administered medication. Pharmaceutical Care Network Europe V8.02-defined drug-related problems were identified. Those that conformed to the Hallas contribution and causality criteria were deemed drug-related hospital admissions and causes of the problems were examined. Main outcome measure An association between self-administration of medications and hospital admission was determined using a multivariable logistic regression analysis. Results The prevalence of drug-related hospital admissions was 20.6% (95% confidence interval, CI 16.4-25.3%) as an overall and was significantly higher in the self-administration group (25.4%) than in the caregiver administration group (12.7%). Among the drug-related hospital admissions in the self-administration and caregiver administration groups respectively, 71.7 and 62.5% were preventable, 63.2 and 37.7% were caused by patient themselves, and 26.3 and 37.5% were from adverse drug reactions. Medical conditions frequently caused by the patients included the exacerbation of chronic obstructive pulmonary disease due to using inhalers less than prescribed or administering drugs in the wrong manner in the self-administration group and hypoglycemia due to a long interval between insulin injection and meal consumption in the caregiver administration group. Compared to caregiver-administered medications, self-administration of medications increased the odds of hospital admission by approximately two-fold (adjusted odds ratio, OR 2.24, 95% CI 1.13-4.43). Other independent risk factors included the use of five or more medications a day (OR 2.65, 95% CI 1.16-6.07), the presence of underlying chronic obstructive pulmonary disease (OR 2.11, 95% CI 1.05-4.23) and self-medication (OR 2.59, 95% CI 1.12-5.99). Conclusion Self-administered medication was associated with hospital admissions in elderly patients with chronic diseases. To prevent problems, priority should be given to interventions to ensure the appropriate administration of inhaled medications for chronic obstructive pulmonary disease and antihyperglycemic agents.