Relationship between hospital specialization and health outcomes in patients with nonsurgical spinal joint disease in South Korea: A nationwide evidence-based study using national health insurance data.

Previous studies on hospital specialization in spinal joint disease have been limited to patients requiring surgical treatment. The lack of similar research on the nonsurgical spinal joint disease in specialized hospitals provides limited information to hospital executives.To analyze the relationship between hospital specialization and health outcomes (length of stay and medical expenses) with a focus on nonsurgical spinal joint diseases.The data of 56,516 patients, which were obtained from the 2018 National Inpatient Sample, provided by the Health Insurance Review and Assessment Service, were utilized. The study focused on inpatients with nonsurgical spinal joint disease and used a generalized linear mixed model with specialization status as the independent variable. Hospital specialization was measured using the Inner Herfindahl-Hirschman Index (IHI). The IHI (value ≤1) was calculated as the proportion of hospital discharges accounted for by each service category out of the hospital's total discharges. Patient and hospital characteristics were the control variables, and the mean length of hospital stay and medical expenses were the dependent variables.The majority of the patients with the nonsurgical spinal joint disease were female. More than half of all patients were middle-aged (40-64 years old). The majority did not undergo surgery and had mild disease, with Charlson Comorbidity Index score ≤1. The mean inpatient expense was 1265.22 USD per patient, and the mean length of stay was 9.2 days. The specialization status of a hospital had a negative correlation with the length of stay, as well as with medical expenses. An increase in specialization status, that is, IHI, was associated with a decrease in medical expenses and the length of stay, after adjusting for patient and hospital characteristics.Hospital specialization had a positive effect on hospital efficiency. The results of this study could inform decision-making by hospital executives and specialty hospital-related medical policymakers.