Long-term mortality after Staphylococcus aureus spondylodiscitis: a Danish nationwide population-based cohort study

Abstract

Objectives: To determine the long-term mortality and the causes of death after Staphylococcus aureus spondylodiscitis.

Methods: Nationwide, population-based cohort study using national registries of adults diagnosed with non postoperative S. aureus spondylodiscitis from 1994-2009 and alive 1 year after diagnosis (n Z 313). A comparison cohort from the background population individually matched on sex and age was identified (n Z 1565). Kaplan-Meier survival curves were constructed and Poisson regression analyses used to estimate mortality rate ratios (MRR) adjusted for comorbidity.

Results: 88 patients (28.1%) and 267 individuals from the population-based comparison cohort (17.1%) died. Un-adjusted MRR for S. aureus spondylodiscitis patients was 1.77 (95% CI, 1.39-2.25) and 1.32 (95% CI, 1.02-1.71) after adjustment for comorbidity. We observed increased mortality due to infectious (MRR 8.57; 95% CI, 2.80-26.20), endocrine (MRR 3.57; 95%CI, 1.01-12.66), cardiovascular (MRR 1.59; 95% CI, 1.02-2.49), gastrointestinal (MRR 3.21; 95% CI, 1.178.84) and alcohol and drug abuse-related (MRR 10.71; 95% CI, 3.23-35.58) diseases.

Conclusions: Patients diagnosed with S. aureus spondylodiscitis have substantially increased long-term mortality, mainly due to comorbidity. To improve survival after S. aureus spondylodiscitis these patients should be screened for comorbidity and substance abuse predisposing to the disease [corrected].

Keywords: Long-term mortality; Prognosis; Spondylodiscitis; Staphylococcus aureus; Vertebral osteomyelitis.