Prevalence of Potentially Inappropriate Medication (PIM) and Factors Associated with PIM in Elderly Outpatient Prescriptions at a District Hospital in the Southern Region of Thailand

Abstract

The aims of study are to know the prevalence of, and to describe factors associated with prescribing PIM at a district hospital in the South of Thailand. A cross-sectional study conducting the retrospective data in a district hospital during October 1, 2011 to September 30, 2012, the study participants were a ≥ 65-year outpatient and had at least 1 prescribed medication from the hospital. Overall, 430 out of 5,265 participants were randomized and their 2,128 prescriptions were examined. The 2012 Beers criteria was applied to detect PIM. Prevalence of PIM were calculated by their total prescriptions. Prescription, patient, and prescriber characteristics associated with PIM were analyzed by logistic regression. Results showed that 39.1% of all participants were female and 53.7% aged 65-74 years; 28.1% of total prescriptions had at least 1 PIM. The highest prevalence of PIM prescription was observed in mental and behavioural disorders, while, Lorazepam was mostly frequent prescribed. Results showed the statistically significantly positive association between the presence of PIM and the number of medications. There was the more likelihood of a patient receiving PIM at outpatient department increased significantly when that patient was prescribed more medications (p<0.01). In addition, the positively associated factors to the presence of PIM were age of participant (OR=1.018, p= 0.040) and age of prescriber (OR=1.105, p=0.046). In contrast, the result showed a likelihood of an elderly outpatient who had more frequent outpatient visits had less PIM prescription as compared to the reference (outpatient visits: 4-6 vs. ≥7: OR = 0.578, p=0.002 vs. OR=0.674, p=0.011, respectively). However, no statistically significant associations between the presence of PIM and participant's gender, number of diagnoses, health insurance schemes, hospitalizations, prescriber's gender, types of prescriber and length of prescriber's years work were observed. In conclusion, similar to other international studies, the prevalence of PIM prescription among elderly outpatients in this study hospital was 28.1%. The significant factors associated with PIM prescriptions were number of medications, participant's age, prescriber's age, and outpatient visits.