The impact of an “acute dialysis start” on the mortality attributed to the use of central venous catheters: a retrospective cohort study

BACKGROUND: Central venous catheters (CVCs) are associated with early mortality in dialysis patients. However, some patients progress to end stage renal disease after an acute illness, prior to reaching an estimated glomerular filtration rate (eGFR) at which one would expect to establish alternative access (fistula/peritoneal dialysis catheter). The purpose of this study was to determine if exclusion of this “acute start” patient group alters the association between CVCs and mortality. METHODS: We conducted a retrospective cohort study of 406 incident dialysis patients from 1 Jan 2006 to 31 Dec 2009. Patients were classified as acute starts if 1) the eGFR was >25 ml/min/1.73 m(2), ≤3 months prior to dialysis initiation and declined after an acute event (n = 45), or 2) in those without prior eGFR measurements, there was no supporting evidence of chronic kidney disease on history or imaging (n = 12). Remaining patients were classified as chronic start (n = 349). RESULTS: 98 % and 52 % of acute and chronic starts initiated dialysis with a CVC. There were 148 deaths. The adjusted mortality hazard ratio (HR) for acute vs. chronic start patients was 1.84, (95 % CI [1.19-2.85]). The adjusted mortality HR for patients dialyzing with a CVC compared to alternative access was 1.19 (95 % CI [0.80-1.77]). After excluding acute start patients, the adjusted HR fell to 1.03 (95 % CI [0.67-1.57]). CONCLUSIONS: A significant proportion of early dialysis mortality occurs after an acute start. Exclusion of this population attenuates the mortality risk associated with CVCs.