Risk Factors and Outcomes of Hematogenous Vertebral Osteomyelitis in Patients With <i>Staphylococcus aureus</i> Bacteremia

Authors/contributors
Abstract
Background Hematogenous vertebral osteomyelitis (HVOM) is an incompletely understood complication of Staphylococcus aureus bacteremia (SAB). Methods Eligible SAB patients with and without HVOM were prospectively enrolled from 1995 through 2019 at Duke University Health System. HVOM was diagnosed either radiographically or microbiologically. Multivariable logistic regression analysis was performed to identify clinical and microbial factors associated with HVOM risk. All bloodstream S. aureus isolates were genotyped using spa typing. Results Of 3165 cases of SAB, 127 (4.0%) developed HVOM. Patients who experienced HVOM were more likely to have community-acquired SAB (30.7% vs 16.7%, P &lt; .001), have a longer time to diagnosis of SAB (median, 5 days; interquartile range [IQR], 2–10.5 vs median, 2 days; IQR, 0–4; P &lt; .001), and to exhibit persistent bacteremia (48.8% vs 20.6%, P &lt; .001). A significant number of HVOM patients developed infective endocarditis (26% vs 15.2%, P = .002). Overall, 26.2% (n = 33) of SAB patients with HVOM underwent surgical intervention. Methicillin resistance (46.6% vs 41.7%, P = .318) and bacterial genotype were not associated with the development of HVOM. At the 12-month follow-up, 22% of patients with HVOM had died. Of the surviving patients, 20.4% remained on antibiotic therapy, and 29.6% had recurrence of either HVOM or SAB. Conclusions Among patients with SAB, HVOM risk was associated with clinical factors and not bacterial genotype. Despite being a rare complication of SAB, patients with HVOM had high all-cause mortality rates and healthcare resource requirements up to 1 year after their HVOM diagnosis. Close clinical monitoring is indicated in this vulnerable population.
Publication
Clinical Infectious Diseases
Date
2023-09-25
Notes

Key Question: What are the risk factors and outcomes associated with hematogenous vertebral osteomyelitis (HVOM) in patients with Staphylococcus aureus bacteremia (SAB)?

Findings:

  • The incidence of HVOM was 4% in this cohort of SAB patients.
  • Risk factors for HVOM included community-acquired SAB, injection drug use, unknown source of bacteremia, longer time to SAB diagnosis, and persistent bacteremia.
  • HVOM patients had higher mortality, longer hospital stays, and increased healthcare utilization in the year after diagnosis compared to SAB patients without HVOM.
  • Neither methicillin resistance nor specific S. aureus genotypes were associated with increased HVOM risk.

Clinical Implications:

  • Clinicians should have increased suspicion for HVOM in SAB patients with community-onset infections, IDU history, unknown source, delays in diagnosis, or persistent bacteremia.
  • Patients with HVOM have poor short and long-term outcomes, requiring close monitoring after diagnosis.
  • HVOM risk is related to clinical not microbial factors.

Strengths:

  • Large, prospective cohort of SAB patients at a single center over 25 years.
  • Detailed clinical data collection with 1-year follow-up.
  • Objective HVOM diagnosis based on imaging and/or microbiological culture.

Limitations:

  • Referral bias, as some HVOM patients were transferred from other hospitals.
  • Details lacking on clinical decision-making for treatment duration, imaging, etc.
  • Small sample size limited subgroup analyses.
  • Did not collect data on history of spine fractures.
Citation
1.
Kinamon T, Dagher M, Park L, Ruffin F, Fowler VG, Maskarinec SA. Risk Factors and Outcomes of Hematogenous Vertebral Osteomyelitis in Patients With Staphylococcus aureus Bacteremia. Clinical Infectious Diseases. Published online September 25, 2023:ciad377.