Patients with active cancer (PAC) and a bloodstream infection caused by Staphylococcus aureus were found to have a significantly decreased risk for incident infective endocarditis (IE) compared with those without cancer (PWC), according to results of a multicenter retrospective cohort study published in Infectious Diseases and Therapy.

Investigators analyzed data collected prospectively from adult patients with and without cancer who were hospitalized for a S aureus bloodstream infection (SABSI) between 2011 and 2019. They compared the incidence of SABSI and S aureus IE between PACs and PWCs. The investigators defined SABSI as at least 1 positive blood cultured obtained from a patient with signs and symptoms of infection.

The investigators collected demographic, epidemiologic, clinical, and microbiologic data from patients with SABSIs. The follow-up period with infectious disease specialists was up to 90 days after hospital admission. The primary outcome was all-cause mortality 30 days after bacteremia onset.


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Among a total of 978 patients included in the analysis, the mean age was 64.6 (SD, 15.9) years, the mean Charlson comorbidity index score was 5.4 points, and 66.3% were male. Compared with PWC, PAC were younger, had fewer chronic comorbidities, and were less likely to receive antiplatelet therapy.

The incidence of SABSI was significantly increased in PWC vs in PAC (7.3 vs 2.9 of 1000 hospital discharges per year; P <.001), with 77.8% of SABSI episodes occurring in PWC and 22.2% occurring in PAC. Although community-acquired SABSI was more common in PWC than in PAC, healthcare-acquired SABSI was more common in PAC (P <.001).

There were 89 patients (9.1%) diagnosed with IE, 6 of whom were PAC. In a univariate analysis that compared patients with IE vs those with other sources of BSI, patients with IE were more likely to report cardiopathy (49.4% vs 16.5%; P <.001), valvulopathy (37.5% vs 14.5%; P <.001), use of cardiac devices (21.3% vs 4.3%; P <.001), and sepsis (44.9% vs 31.2%; P <.008). Of note, patients with IE were less likely to have an underlying malignant disease vs those with a BSI from other sources (6.7% vs 23.7%; P <.001).

Results of a multivariate analysis showed that previous cardiopathy (adjusted odds ratio [aOR], 4.392; 95% CI, 2.719-7.094; P <.001) and persistent bacteremia (aOR, 3.545; 95% CI, 2.159-5.820; P <.001) were the only risk factors independently associated with IE. Of note, active cancer, both solid organ tumor and hematologic malignancy, was identified as a protective factor (aOR, 0.338; 95% CI, 0.142-0.806; P =.011).

There were no differences found in all-cause 30-day mortality between PAC and PWC. Risk factors that remained independently associated with 30-day mortality in a multivariate analysis included being older than 65 years, a Charlson comorbidity index score of greater than 6 points (aOR, 1.881; 95% CI, 1.265-2.797; P =.002), unknown source of infection (aOR, 2.759; 95% CI, 1.650-4.611; P <.001), sepsis (aOR, 7.578; 95% CI, 5.177-11.090; P <.001), infection due to methicillin-resistant S aureus (aOR, 1.619; 95% CI, 1.006-2.608; P <.047), and persistent bacteremia (aOR, 5.666; 95% CI, 3.314-9.687; P <.001).

This study was limited by its retrospective design and the decreased prevalence of IE in PWC.

According to the investigators, “[this] study suggests that PAC without previous cardiopathy and with rapid clearance of bacteremia [are at a decreased] risk of developing IE.”

Disclosure: One author declared an affiliation with the Spanish Network for Research in Infectious Diseases. Please see the original reference for a full list of disclosures.

Reference

Grillo S, Cuervo G, Laporte-Amargós J, et al. Bloodstream infection and endocarditis caused by Staphylococcus aureus in patients with cancer: A multicenter cohort study. Infect Dis Ther. Published online December 2, 2021. doi:10.1007/s40121-021-00575-8

This article originally appeared on Infectious Disease Advisor