Potentially inappropriate prescribing and drug-drug interactions among elderly Chinese nursing home residents in Macao

Background The ageing of the population has become a concern all over the world, including Macao. In general, older people are more prone to adverse drug events which can result from potentially inappropriate medication (PIM) use and drug-drug interactions (DDIs). Objective This study was designed to evaluate the prevalence of PIM use and DDIs among elderly nursing home residents in Macao, and to find out the factors associated with these drug-related problems. Setting This study was conducted in the largest nursing home in Macao, with a bed capacity of 168. Method All data of this cross-sectional study were collected from medical charts and medication administration records. PIM use was determined by the screening tool of older person's prescription (STOPP) criteria and potential DDIs were detected using the preset criteria of two compendia, Drug-Reax and Lexi-Interact. Multivariate logistic regression analysis was performed to identify the independent factors associated with each drug-related problem. Main outcome measures The proportions of elderly nursing home residents who regularly used PIMs and who were exposed to DDIs. Results A total of 114 elderly residents were eligible for PIM analysis. They consumed an average of 6.9 ± 3.1 different medications. About 46.5 % of them regularly used one or more PIMs. The prevalence of DDIs was 37.8 % among the 111 elderly residents who consumed at least two different medications. An increased number of drugs used was identified as the independent factor associated with PIM use and DDIs (p < 0.05). However, the use of STOPP-related PIMs did not appear to raise the likelihood of DDIs among the study population. Conclusion Both PIM use and DDIs are common among elderly nursing home residents in Macao. Further studies should be conducted to evaluate the clinical outcomes of pharmacist-led interventions for elderly residents in the local nursing home setting.