Background In South Korea, injured people due to road traffic accident could receive compensation for medical cost through automobile insurance. However, automobile insurance system in health care utilization seems to be managed inefficiently. This study aimed to investigate which hospital factors were associated with length of stay (LOS) as an indicator of health care utilization under automobile insurance in inpatients with invasive cervical discectomy.

Methods We used automobile insurance claim data from 158 hospitals, consisting of 850 inpatients during 2014-2015. Poisson regression analysis was analyzed to examine the association between LOS and hospital level variables after adjusting for both inpatient and hospital level variables.

Results The average LOS under automobile insurance was 25.75 days. A higher proportion of inpatients with automobile insurance were associated with longer LOS (relative risk (RR): 1.027 per 1% increase, 95% CI: 1.012 to 1.042). In addition, such associations were significant only in hospitals with small sized and low volume. A higher hospital volume of invasive cervical discectomy (RR: 0.970 per 10 cases increase, 95% CI: 0.945 to 0.997), bed turnover rate (RR: 0.988 per 1 increase, 95% CI: 0.979 to 0.997), and number of neurosurgeric or orthopedic specialists (RR: 0.930 per 1/100 beds increase, 95% CI: 0.876 to 0.987) was associated with shorter LOS.

Conclusions Our findings suggest that higher proportion of inpatients with automobile insurance was associated longer LOS in hospitals with small sized and low provider volume including surgeon and hospital volume. On the basis of these findings, health policy makers and healthcare professionals should consider proper strategies for efficient management of automobile insurance and small sized hospitals.