Attributable vs Crude Mortality in Candida Bloodstream Infections

The rate of 90-day all-cause mortality attributable to candida bloodstream infections (BSI) was found to be significantly increased among patients who were the least likely to develop candida BSI, according to results of a study published in Clinical Infectious Diseases.

This study was conducted at the Barnes-Jewish Hospital in Saint Louis, Missouri between 2012 and 2019. Patients (n=634) diagnosed with Candida BSI were matched in a 1:10 fashion against patients (n=6340) without candida BSI who had at least 1 risk factor commonly associated with an increased risk for the infection. Common risk factors associated with candida BSI were presence of central venous catheter (CVC) or hemodialysis catheter, prior surgical procedure, stem cell transplantation, history of substance use disorder, myelodysplastic syndrome (MDS), metastatic cancer, pancreatitis, chronic liver disease, and acute kidney injury. The primary outcome was 90-day all-cause mortality.

Among patients in both the positive and negative candida BSI groups, the median age was 58 (IQR, 46-66) and 61 (IQR, 52-70) years; 42.8% and 47.1% were women; 69.8% and 73.4% were White; 54.0% and 53.9% had a CVC or hemodialysis catheter; and 22.8% and 22.6% had leukemia, MDS, or had undergone bone marrow transplantation, respectively.

All-cause mortality at 30 days occurred among 24.6% and 11.5% of patients in the positive vs negative candida BSI groups, respectively. The rate of all-cause mortality at 90 days was 42.4% among patients in the positive candida BSI group vs 17.1% among those in the negative group. These rates indicated a crude group difference in all-cause mortality of 13.1% at 30 days and 25.3% at 90 days.

The researchers performed a propensity score-matched analysis and found that mortality attributable to candida BSI was increased at both 30 (hazard ratio [HR], 1.68; 95% CI, 1.56-1.80) and 90 (HR, 2.12; 95% CI, 1.98-2.25) days.

After stratification by risk quintiles, the greatest increased risk of mortality attributable to candida BSI was observed among patients in the lowest risk quintile at both 30 (HR, 2.35; 95% CI, 1.75-3.15) and 90 (HR, 3.13; 95% CI, 2.33-4.19) days. Patients in the second lowest risk quintile were also found to have an increased risk of mortality at both 30 (HR, 1.78; 95% CI, 1.32-2.41) and 90 (HR, 1.97; 95% CI, 1.46-2.67) days. The researchers found no increase in the risk of mortality among patients in the highest 3 risk quintiles for candida BSI compared with those in the negative candida BSI group.

Among a subset of untreated patients with candida BSI (n=32), most were in the lowest 2 risk quintiles (68.7%). The odds ratio (OR) for mortality among untreated patients in the lowest risk quintile was 3.3 (95% CI, 2.0-5.4).

Limitations of this study included a lack of generalizability due to its single-center setting, potential unmeasured confounding due to its observational design, and the exclusion of patients who died within 24 hours of index blood culture.

The researchers concluded, “it is imperative that clinicians maximize efforts to adhere to guideline recommendations and seek infectious disease consultation to assist in timely, efficacious treatment of candida BSI.”

Disclosure: Multiple authors declared affiliations with industry. Please see the original reference for a full list of disclosures.

Reference

Mazi PB, Olsen MA, Stwalley D, et al. Attributable mortality of Candida bloodstream infections in the modern era: A propensity score analysis. Clin Infect Dis. 2022;ciac004. doi:10.1093/cid/ciac004