This study aims to estimate the volume of unnecessarily utilized hospital outpatient services in Korea and quantify the total cost resulting from the inappropriate utilization. The analysis included a sample of 27,320,505 outpatient claims from the 2009 National Inpatient Sample database. Using the Charlson Comorbidity Index (CCI), patients were considered to have received 'unnecessary hospital outpatient utilization' if they had a CCI score of 0 and were concurrently admitted to hospital for treatment of a single chronic disease - hypertension (HTN), diabetes mellitus (DM), or hyperlipidemia (HL) - without complication. Overall, 85% of patients received unnecessary hospital services. Also hospitals were taking away 18.7% of HTN patients, 18.6% of DM and 31.6% of HL from clinics. Healthcare expenditures from unnecessary hospital outpatient utilization were estimated at: HTN (94,058 thousands USD, 38.6% of total expenditure); DM (17,795 thousands USD, 40.6%) and HL (62,876 thousands USD, 49.1%). If 100% of patients who received unnecessary hospital outpatient services were redirected to clinics, the estimated savings would be 104,226 thousands USD. This research proves that approximately 85% of hospital outpatient utilizations are unnecessary and that a significant amount of money is wasted on unnecessary healthcare services; thus burdening the National Health Insurance Service (NHIS) and patients.
Keywords: Costs and Cost Analysis; Primary Health Care; Referral and Consultation; Utilization.