Survey of drug inventory control process and performance among hospital pharmacy departments in Thailand

Abstract

The objectives of this study were to explore the processes of drug inventory control systems, as well as develop and evaluate the performance indicators of drug inventory control system. The study design was a cross-sectional survey research. It was conducted in two parts. The first part was the development of major drug inventory indicators. A list of drug inventory indicators from literature review was assessed by 20 hospital pharmacists and 9 experts according to the 3 criteria of the good indicators. The second part was a survey of drug inventory process and performance by mailing questionnaire to 720 samples of both public and private hospitals in Thailand. Descriptive statistics were used to explain the process and performance of drug inventory control. Then, the Mann-Whitney U test and Kruskal- Wallis tests were used to find out the association between the processes and performances. Nine indicators were selected as major drug inventory controls: the percentage of essential drug stock outs, the percentage of drug stock outs at dispensing unit, the percentage of error in receiving drugs per purchasing order, a list of expired drugs, total cost of expired drugs in a year, the average months of drug inventory, the list of non-movement drugs exceeding 3 months period, a list of drugs not being issued to customers and the number of customer complaints. For the second part, the overall response rate of this study was 42.92% (309 from 720 hospitals). When hospitals were categorized according to type and bed sizes, there were differences in the drug inventory control processes. As a result, the drug inventory performance and outcomes were also different. A combination of good drug inventory system was ABC, VEN system, group purchasing, verification of quantity in drug issuing according to the real usage, drugs accepted with the expiration dates more than one year, and vendor performance evaluation. Another important finding was that the level of drug inventory value (Baht/OPD visit) in each size of hospital could be used as a benchmark to improve their drug inventory process and performance. The results of this study demonstrated a benchmark of inventory value and provided a thorough understanding of drug inventory processes and their impact on drug inventory performance. The study results can serve as a guideline for hospital pharmacists in both the public and private sectors and help them maximize the efficiency of drug inventory systems.