Vertebral osteomyelitis in patients with infective endocarditis: prevalence, risk factors and mortality

Infective endocarditis (IE) can be complicated by vertebral osteomyelitis (VO). This study investigates risk factors associated with VO in patients with infective endocarditis, and 6-month mortality and relapse rates in patients with IE and concomitant VO.

We performed a observational study in two hospitals between September 2016 and October 2022. Patients with possible or definite IE according European Society of Cardiology (2015) modified criteria were retrieved from the local endocarditis team registries. The VO diagnosis was based on radiological signs, irrespective of clinical symptoms. Multivariable logistic regression analysis was performed to identify risk factors for vertebral osteomyelitis.

We included 633 consecutive patients with IE. A total of 229 (36.2%) patients had prosthetic valves and 127 (20.1%) had cardiac implantable electronic devices. The most frequent causative micro-organism was Streptococcus species (217, 34.3%), followed by Staphylococcus aureus (167, 26.4%). VO was diagnosed in 73 patients (11.5%, 95% CI 9.0%-14.0%). Enterococcus spp.(OR 2.48, 95% CI 1.31-4.52) and age (OR 1.04 per year, 95% CI 1.02-1.06) were independently associated with concomitant VO. The 6-month mortality risk did not differ between patients with (16/73, 21.9%) or without (110/560, 19.6%) VO (HR 1.13, 95% CI 0.67-1.91). Relapse rate was higher in patients with VO but the difference was not statistically significant (16.1 vs. 7.5%, OR 3.62, 95% CI 0.94-13.34).

Twelve percent of patients with IE also had VO. Among older patients and patients with IE caused by enterococci, there should be a higher index of suspicion for vertebral infection.