Bloodstream infections in patients with kidney disease: risk factors for poor outcome and mortality

Abstract

Background: Information regarding bloodstream infections (BSIs) in patients with kidney diseases is scarce and mainly derived from selected groups of patients.

Aim: To assess the characteristics of BSI in an unselected population of patients with kidney disease, including renal transplant recipients and patients with chronic kidney failure who were receiving or not receiving dialysis.

Methods: A retrospective cohort study of all patients who presented with BSI in the nephrology department of a large teaching hospital. Clinical records were reviewed according to a pre-established protocol. Standard definitions were used.

Findings: In all, 155 episodes of BSI were recorded in 108 patients. The incidence of BSI was 77.3 episodes per 1000 admissions, and 4.5 episodes per 100 patient-years. Haemodialysis patients had the highest incidence of BSI. The distribution of micro-organisms was as follows: Gram-negative, 52.3%; Gram-positive, 46.5%; fungi, 1.2%. Escherichia coli was the most frequently isolated micro-organism (27%). The BSI was classed as bacteraemia of unknown source (29.7%), urinary tract infection (23.2%), vascular access infection (17.4%), and other (29.7%). Eighteen patients (11.6%) developed septic shock or multi-organ failure, and the same proportion had persistent bacteraemia. The crude mortality rate was 14.6%. The risk factors for mortality were high Charlson index, persistent bacteraemia, and absence of fever.

Conclusion: Nephrology patients have a high incidence of BSI, particularly patients undergoing haemodialysis. The predominant micro-organisms causing BSI episodes were Gram-negative bacilli. Patients with kidney disease have high BSI-related morbidity and mortality. Risk factors for mortality were high Charlson comorbidity index and persistent BSI. The presence of fever during the BSI episodes was found to be a protective factor.

Keywords: Bacteraemia; Chronic kidney disease; Mortality; Peritoneal dialysis; Renal transplantation.