Using Nonparametric Control Chart to Build a Surveillance Mechanism of Medical Care Expenses

Abstract

According to the Diagnosis Related Groups (DRGs) policy initiated in Taiwan in 2010, hospital payments within a given diagnosis group should be fixed, making it critical for hospitals to monitor growth of medical care costs. This study investigates how to monitor the cost of unusual factors on single vessel percutaneous transluminal coronary angioplasty (PTCA) and attempts to build a surveillance mechanism for DRGs medical care expenses. This investigation sampled objects from the National Health Insurance Database of Taiwan during 2010. This study analyzed variation in fees of single vessel PTCA in selected medical centers, and chose inpatients over 17 years old as objects for study. This study used two nonparametric control charts, Nonparametric Shewhart control chart and Nonparametric Exponentially Weighted Moving Average control chart, contributing further to constructing the mechanism for surveying medical care expenses. The selected medical center underwent construction changes, and medical expenses rose gradually increased following August 2010. The selected medical center thus had good fiscal control of single vessel PTCA surgery, and the medical expenses for most cases were lower than the standardized payment rate of National Health Insurance. This study used a Nonparametric Shewhart control chart to analyze monthly medical costs and identify unusual months. This approach was suitable for monitoring large changes in process. This study also used the Nonparametric Exponentially Weighted Moving Average control chart to estimate the current data and long-term trend data to reduce Nonparametric Shewhart control chart error, because this could not be achieved by analyzing past long-term trends. Nonparametric Exponentially Weighted Moving Average control chart had better detection of small process changes and achieved early awareness of gradual financial losses. This study used two nonparametric control charts to build the surveillance mechanism for DRGs. This study provided effective information to medical providers seeking to maintain health care quality and obtain sufficient profits to enable sustainable development by developing a mechanism for surveying medical care expenses.