OBJECTIVES: The objectives of this study were to review the characteristics of patients admitted with septic arthritis in Spanish hospitals and to measure the associated direct medical costs.

METHODS: Records of hospital admissions of patients with septic arthritis as a primary diagnosis registered between 2010 and 2019 were evaluated in a retrospective study. Admission costs in the database were based on the diagnosis-related group-based hospital payment systems, determined by the Spanish Ministry of Health.

RESULTS: Files from 16,438 patients were evaluated; median age was 56 years and 62.8% of patients were males. The knee was the most commonly involved joint, registered in 49% of the cases. The most frequently registered pathogen was Staphylococcus, and 2.7% of admissions registered an antibiotic resistant infection. Most of the admissions were urgent or non-scheduled, and median hospitalization time was 14 days for adult patients and 8 days for children. An intensive care unit (ICU) stay was registered in 4.5% of hospital admissions, with a median length of ICU stay of 3 days. The in-hospital mortality rate was 3.7% for adult patients; median age of deceased patients was 81 years, and no deaths were registered in children. Median admission cost was €6382 per patient, with no significant differences between age groups. Admission cost increased significantly with length of hospital stay. In addition, admissions in which an arthrotomy was registered had a significantly lower cost than those without an arthrotomy in all age groups. The total annual medical cost was 12.7 million euros.

CONCLUSIONS: This study provides new data on the medical costs of septic arthritis in Spain, providing a basis for the revision of resource allocation decisions in order to reduce the burden of this condition at the healthcare system level. Further research will be required to quantify the total burden associated to this condition.