Results of the Forecast of Drug Order Quantity Using the ABC-VEN Analysis and Three Months Moving Average: A Case of Sriboonruang Hospital

Abstract

Objective: To compare the results before and after the development of drug procurement system by using the drug classification according to the ABC-VEN analysis and three months moving average to forecast drug order quantity. Methods: The study collected the data on quantity of use in Sriboonruang hospital for the past 3 fiscal years (2019-2021) in all 355-drug items purchased by itself. The study used such drug use information to prepare a purchasing plan for the fiscal year 2022 and to classify drugs according to the ABC-VEN analysis. Subsequently, drug purchasing was carried out according to the forecasted order quantity calculated using the 3 months moving average. The study compared average drug inventory rates, drug shortage percentages, and expired drug percentages before and after system implementation (April 2021 to September 2021 and October 2021 to March 2022, respectively). Results: The numbers of drug items according to the ABC-VEN grouping were 15 items in AV group (4.2%), 16 items (4.5%) in BV group, 60 items (16.9%) in CV group, 56 items (15.8%) in AE group, 66 items (18.6%) in BE group, 105 items (29.6%) in CE group, 4 items (1.1%) in AN group , 11 items (3.1%) in BN group and 22 items (6.2%) in CN group. The AN group had the smallest mean absolute percentage error at 20.96%. After the implementation of the system, average six-month drug inventory rate decreased from 83.56 to 58.80 days. Drug shortage percentage also decreased from 2.25 to 1.13%. No expired drugs were found both before and after the system implementation. Conclusion: The purchasing system based on the ABC-VEN analysis and three months moving averages forecasting helps decrease drug inventory and drug shortage. In addition, there was no expired drugs.