Incidence of bloodstream infection in multicenter inception cohorts of hemodialysis patients

Abstract

Objective To assess incidence of and identify risk factors for bloodstream infection in patients starting hemodialysis or starting a new means of vascular access for hemodialysis. Method Two cohorts of patients, 1 initiating hemodialysis (new patients) and a 1:1 matching group of patients continuing hemodialysis but starting a new vascular access (continuing patients), were enrolled from 9 Canadian hemodialysis units and followed for 6 months. Bloodstream infection was defined using established criteria. A nested case-control study was carried out, using as cases those cohort patients diagnosed with infection. Each case was matched with a control having the same means of access and new or continuing status. Results A total of 527 patients (258 new, 269 continuing), were recruited and underwent 31,268 hemodialysis procedures during this 6-month follow-up. There were 96 bloodstream infections in 93 patients (11.97/10,000 days, 28.81/10,000 hemodialysis procedures), yielding a relative risk of infection of 3.33 (95% CI, 2.12-5.24) for patients with a previous bloodstream infection and 1.56 (95% CI, 1.02-2.38) for patients continuing hemodialysis by a new means of access. Survival analysis revealed that compared to arteriovenous fistula vascular access, the relative risk of bloodstream infection in patients was 1.47 (95% CI, 0.36-5.96) for arteriovenous grafts, 8.49 (95% CI, 3.03-23.78) for cuffed central venous catheters, and 9.87 (95% CI, 3.46-28.20) for uncuffed central venous catheters. The regression model of the case-control study identified earlier bloodstream infection (OR, 6.58), poor patient hygiene (OR, 3.48), and superficial access-site infection (OR, 4.36) as additional risk factors. Conclusion During the first 6 months there is a high rate of bloodstream infection in patients starting hemodialysis either for the first time or by a new means of vascular access. Previous hemodialysis bloodstream infection and continuing hemodialysis by a new means of vascular access are markers for an increased risk of infection, as is poor patient hygiene. Central venous catheter vascular access, whether cuffed or uncuffed, has a much higher infection risk. In this study, there was no difference in infection rate between cuffed and uncuffed central catheters.