Assessing the performance of a method for case-mix adjustment in the Korean Diagnosis-Related Groups (KDRG) system and its policy implications

Sujeong Kim,Sangmin Lee,Kyunghee Lee,Byoongyong Choi,Sukil Kim

doi:10.1186/s12961-021-00739-5

Abstract

BackgroundTo evaluate the performance of the patient clinical complexity level (PCCL) mechanism, which is the patient-level complexity adjustment factor within the Korean Diagnosis-Related Groups (KDRG) patient classification system, in explaining the variation in resource consumption within age adjacent diagnosis-related groups (AADRGs).MethodsWe used the inpatient claims data from a public hospital in Korea from 1 January 2017 to 30 June 2019, with 18 846 claims and 138 AADRGs. The differences in the total average payment between the four PCCL levels for each AADRG was tested using ANOVA and Duncan’s post hoc test. The three patterns of differences with R-squared were as follows: the PCCL reflected the complexity well (valid); the average payment for PCCL 2, 3, and 4 was greater than PCCL 0 (partially valid); the PCCL did not reflect the complexity (not valid).ResultsThere were 9 (6.52%), 26 (18.84%), and 103 (74.64%) ADRGs included in the valid, partially valid, and not valid categories, respectively. The average R-squared values were 32.18, 40.81, and 35.41%, respectively, with an average R-squared for all patterns of 36.21%.ConclusionsAdjustment using the PCCL in the KDRG classification system exhibited low performance in explaining the variation in resource consumption within AADRGs. As the KDRG classification system is used for reimbursement under the new DRG-based prospective payment system (PPS) pilot project, with plans for expansion, there should be an overall review of the validity of the complexity and rationality of using the KDRG classification system.

Highlights

To evaluate the performance of the patient clinical complexity level (PCCL) mechanism, which is the patient-level complexity adjustment factor within the Korean Diagnosis-Related Groups (KDRG) patient classification system, in explaining the variation in resource consumption within age adjacent diagnosis-related groups (AADRGs)
The PCCL score and DRG code per episode were automatically assigned by the DRG grouper distributed by the Health Insurance Review and Assessment Service (HIRA), which is responsible for the development of the KDRG classification system
Of the 532 AADRGs, 138 (25.94%) AADRGs in 18 846 (70.36%) claims were included for analysis

Summary

Introduction

To evaluate the performance of the patient clinical complexity level (PCCL) mechanism, which is the patient-level complexity adjustment factor within the Korean Diagnosis-Related Groups (KDRG) patient classification system, in explaining the variation in resource consumption within age adjacent diagnosis-related groups (AADRGs). The main method for payment is the fee-for-service model, with no separate payments between hospitals and doctors by the National Health Insurance System. The single public insurer (National Health Insurance Service, NHIS) pays 80% of the hospital charge for inpatient stay, and the patient pays the remainder. The mandatory DRG-based PPS, including payments for both hospitals and doctors, targets seven relatively simple surgical disease groups, and was first introduced to certain clinics and hospitals in July 2012. The new DRG-based PPS targeted public hospitals with physician procedures, expensive therapeutic materials, and some expensive drugs paid separately as fee-forservice payments in the system. Since 2018, the new DRG-based PPS has been extended to private hospitals through voluntary participation

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