Dialysis Bloodstream Infections Higher With Central Lines

Veronica Hackethal, MD

June 29, 2017

Patients undergoing kidney dialysis with central venous catheters (CVCs) continue to have higher rates of bloodstream infections than those with other vascular access types, according to a new study.

Duc B. Nguyen, MD, from the Centers for Disease Control and Prevention, Atlanta, Georgia, and colleagues published their findings online June 29 in the Clinical Journal of the American Society of Nephrology.

Most commonly, these infections were caused by Staphylococcus aureus, which was drug resistant in many cases.

The report represents the first truly national report of dialysis-related events, with data from almost all US outpatient dialysis facilities.

"We now have a clearer picture of the rates and types of infections hemodialysis patients in the United States are experiencing — nearly all US outpatient hemodialysis facilities are participating in [Centers for Disease Control and Prevention's National Healthcare Safety Network (NHSN)] Dialysis Event surveillance. Our findings emphasize the need for hemodialysis facilities to improve infection prevention and vascular access care practices," Dr Nguyen said in a news release.

Starting in 2012, all Medicare-licensed outpatient hemodialysis centers were required to report access-related infections to the NHSN, which now houses data from 94% of Medicare-certified outpatient dialysis facilities in the United States. As part of the End-Stage Renal Disease Quality Incentive Program, the Centers for Medicare & Medicaid Services began evaluating dialysis center performance using NHSN data in 2014.

Undergoing hemodialysis can increase the risk for bloodstream and related infections as a result of the frequent need to access the blood. Frequent use of antimicrobials to treat these infections can contribute to the development of multidrug-resistant organisms.

Blood is usually accessed for hemodialysis by creating an arteriovenous fistula (AVF) or arteriovenous graft (AVG), or placing a CVC. An AVF creates a long-lasting connection between the patient's artery and vein. An AVG uses a plastic conduit to create a similar connection between the artery and vein. A CVC catheter is a tube usually inserted into a large vein in the arm, chest, or neck, and can be prone to infection.

The study included NHSN data from 6005 outpatient dialysis centers, which reported 160,971 dialysis events in 2014. Of these, 18.3% (n = 29,516) were bloodstream infections (diagnosed by positive blood culture), 93.0% (n = 149,722) were initiations of intravenous antibiotics or antifungals, and 23.8% (n = 38,310) were cases of local access site infections (pus, redness or swelling at the vascular access site).

Of the total bloodstream infections, 76.5% (n = 22,576) were related to vascular access.

Most bloodstream infections (63.0%) and access-related bloodstream infections (69.8%) happened in individuals with a CVC. Patients with CVCs also experienced higher rates of intravenous antimicrobial starts and local access site infections than those with AVFs or AVGs.

Individuals with a CVC also experienced the highest rates of dialysis-related hospitalization. Among patients hospitalized for a dialysis event (n = 35,286), 49.3% (n = 17,392) had a CVC, 35.6% (n = 12,556) had an AVF, and 14.7% (n = 5199) had an AVG.

The most commonly isolated organism from bloodstream infections was S aureus (30.6%), of which 39.5% had methicillin resistance. A large percentage of methicillin-resistant S aureus came from patients with CVCs (59.3%).

Vancomycin accounted for the majority (75.7%; n = 113,284) of intravenous antimicrobial starts.

"Gross Underreporting"?

Dialysis centers may be underreporting bloodstream infections, and the quality of data reporting needs improvement, the authors write. Susceptibility testing is also suboptimal: 17.8% of S aureus isolated had no data on methicillin susceptibility.

Nevertheless, they note these results are similar to past studies suggesting higher rates of bloodstream infections in hemodialysis patients with CVCs compared with other vascular access types.

"Given the high rate of infections among CVC patients, continued efforts to limit CVC use are needed," they conclude.

In a linked editorial, Dana Miskulin, MD, from Tufts University Medical Center, Boston, Massachusetts, and Ambreen Gul, MD, from Dialysis Clinic Inc, Albuquerque, New Mexico, agree these data lend support to the "Catheter Last" campaign. They urge the dialysis community to "clean up the data."

The editorialists suspect gross underreporting of dialysis-related events to the NHSN, which relies on the honor system without processes in place to ensure accurate reporting. Although reporting bloodstream infections may place a higher workload on clinic staff, the editorialists also think dialysis centers may have "less innocent" reasons for underreporting data, such as financial disincentives.

"The inaccuracies of the data, whether by error or intention, undermines the Quality Improvement Project and reduces opportunities for quality improvement, penalizes those that have been honest and taken care to collect their data accurately and, perversely, may have put patients at more risk if efforts are being made to reduce the diagnosis of a blood stream infection," they write.

They propose mandatory direct reporting by the laboratory to the NHSN of all positive blood cultures originating in outpatient dialysis centers or drawn within 48 hours of hospitalization.

The authors and editorialists have disclosed no relevant financial relationships.

CJASN. Published online June 29, 2017.

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