In-Hospital mortality in Spondylodiscitis: Risk factors assessed through the National Inpatient Sample analysis

Spondylodiscitis (SD) poses an increasing challenge to healthcare providers by its insidious onset and diverse clinical manifestations, concurrent with an aging population, immunocompromising conditions and various influencing comorbidities. Overall mortality remains relatively high, up to 7.3%, despite advancements in diagnostics and treatment. Past studies have struggled to differentiate leading causes for mortality. With this study we want to utilize the large data group available through the National Inpatient Sample (NIS) to assess the in-hospital mortality in patients with SD in different age-groups and to identify risk factors.

Utilizing the 2020 NIS, Healthcare Utilization Project (HCUP) adults (>18 years) were screened using the primary diagnosis of SD by ICD-10 Code (M46.2x, M46.3x and M46.4x). Demographic information, admission details, clinical data, comorbidities, and surgical treatment were extracted using the Clinical Classifications Software Refined (CSSR) categories. Comorbidities include pre-existing conditions and those acquired during hospitalization. Age was categorized into 3 groups (<65 years; 65-79: ≥ 80). The primary outcome was in-hospital mortality, with multivariable logistic regression analysis used to identify independent risk factors.

In total 3,975 patients met our inclusion criteria resulting with an in-hospital mortality rate of 0.9 %. The mortality group was significantly older (70.86 years to 58.74 years compared to the survival group) with elective admission being more common (p=<0.001) with a similar sex distribution. Patients ages 65-79 were more common in the mortality group. Overall fourteen comorbidities differed significantly between the two groups. Chronic diseases were more common in the mortality group, whereas alcohol and substance abuse were more prevalent in the survival group. Age, especially patients < 65 years, elective admission status, paralysis and pneumonia were identified as independent risk factors for mortality.

Management of SD remains complex. Our study revealed a lower rate of in-hospital mortality and length of stay than previous studies. Elective admission status was the strongest predictor of mortality, highlighting the benefits of early diagnosis and treatment. Patients > 65 years, especially octogenarians, were identified to be particular at risk. Risk factors contributing to mortality in SD may differ from etiological risk factors, highlighting areas for potential further research.