Development of MY-DRG Casemix Pharmacy in-patient service weights in UKM Medical Centre, Malaysia

Abstract

The service weight is among several issues and challenges in the implementation of casemix in developing countries, including Malaysia. The aim of this study is to develop the Malaysian Diagnosis Related Group (MY-DRG) casemix pharmacy service weight in University Kebangsaan Malaysia-Medical Center (UKMMC) by identifying the cost of pharmacy services by each casemix groups in the hospital. All patients admitted to UKMMC in 2011 were recruited in this study. Combination of step-down and bottom-up costing methodology was used in this study. The drug and supplies cost, the cost of staff, the overhead cost and the equipment cost make up the four components of pharmacy cost. The total pharmacy cost was obtained by summing all the pharmacy components’ cost per each MY-DRG. Descriptive analyses, bivariate correlation and multiple linear regression analyses were conducted to predict the total pharmacy cost from various potential predictors. A total of 13,673 patients were investigated with average age of 43.53 years (SD 22.27 years) of which 5,767 (42.2%) were males and 7,906 (57.8%) were females. Majority were Malay (49.3%), followed by Chinese (27.8%), Indian (13.8%), others (9.1%) respectively. Majority of cases were medical cases (61.9%) compared to (38.1%) as surgical cases. Most of the patients (53.6%, n=7,329) were in severity level I, 30.8% (n=4,210) patients were in severity level II and 15.6% (n=2,134 patients) were in severity level III respectively. The average length of stay is 6.76 (SD 7.16) days and median of 4 days. The total number of drugs and supplies (items) prescribed for all 13,673 patients were over 111,794 items with average of 8.18 (SD=5.81) and median of 6 items. Drugs and supplies were the main component (86.0%) of pharmacy cost compared to overhead cost (7.3%), staff cost (6.5%) and pharmacy equipments (0.2%) respectively. Out of 789 inpatient MY-DRGs casemix groups, 450 (57.0%) groups were utilized by the UKMMC. Pharmacy service weight was calculated for each of these 450 MY-DRGs groups. MY-DRG casemix group of Lymphoma & Chronic Leukemia group with severity level three (C-4-11-III) has the highest pharmacy service weight of 11.8 equivalents to average pharmacy cost of RM 5,384. While the MY-DRG casemix group for male circumcision with severity level one (V-1-15-I) has the lowest pharmacy service weight of 0.04 equivalents to average pharmacy cost of RM 18. The multivariate model with demographic and clinical variables explained 32.7% of variance in total pharmacy cost, F (8, 13,664) = 829.328, P < 0.0005, R2 = 0.327. Length of stay (B = 0.349, P <0.0005) and severity level III (B = 0.253, P < 0.0005) appeared to be the strongest predictors of the total pharmacy cost; followed by the number of items (B = 0.081, P < 0.0005) and severity level II (B = 0.050, P = <0.0005). In conclusion, increase in the hospitalization period accompanied with a major complication and comorbidity had the highest influence on the total pharmacy cost. Knowing which DRG consumes the bulk of the resources would greatly support decision makers regarding budget planning of pharmacy services and patients’ outcomes, and eventually will contribute in the quality of care and services improvement as well as an efficient use of resources in UKMMC.