Research indicates that despite efforts to increase arteriovenous fistula (AVF) and graft (AVG) use—through the Fistula First Catheter Last Initiative (FFCL)—because of the higher mortality and infectious complications associated with central venous catheters (CVCs), 80% of patients in the United States start hemodialysis on a CVC. Studies have also shown “that nonwhite patients tend to initiate hemodialysis with AVF less frequently than white patients, even when controlling for factors such as age, comorbidities, medical insurance status, and nephrology care,” explains Shipra Arya, MD, SM, FACS. “Combined with evidence that AVFs are also less prevalent in women, this suggests racial/ethnic and sex differences in incident AVF access, although evidence also supports biologic reasons for these disparities.”
Uncovering Disparities
The inclusion of an access type indicator in Medicare dialysis claims beginning in 2010 allowed Dr. Arya, Elizabeth George, MD, and colleagues to take an innovative approach to studying the natural history of CVC use and longitudinal use of hemodialysis access that was not possible prior. For a study published in the Journal of the American Society of Nephrology, the researchers explored the transition from CVC to AVF or AVG among a Medicare-eligible population who started hemodialysis on a CVC between 2010 and 2013 in order to determine any sex or racial disparities in these dialysis access quality metrics. An examination of longitudinal measures of CVC access was followed by a competing-risk model.
“We found that the average patient in the US waited approximately 7 months on dialysis with a CVC before transitioning to a permanent access,” says Dr. Arya (Figure). “At 1 year after hemodialysis initiation, 32.7% of patients had transitioned to AVF and 10.8% to AVG, while 32.1% stayed on a CVC and one-quarter had died.” Women spent significantly longer on CVC than did men, as did patients who were black, Hispanic, or of another racial/ethnicity minority when compared with white patients. “Overall, more patients transitioned to AVF than AVG, even when stratified by sex and race/ethnicity,” Dr. George adds. “At 1-year follow-up, a higher percentage of women had transitioned to AVG compared with men, and there were similar rates of both death and continued CVC use among men and women. Similarly, double the proportion of black patients transitioned to AVG compared with white patients. Interestingly, 1-year mortality was higher in whites compared with blacks, Hispanics, and other ethnicities, so the differences are not entirely explained by concerns for durability of dialysis access.”
As expected, proactive placement of a permanent access decreased the median time patients underwent hemodialysis through a CVC. “What is more surprising,” says Dr. George, “are the racial, ethnic and gender disparities in length of time on a CVC despite having an access site in place. Specifically, women had 2-3 weeks longer transition time regardless of whether there was permanent access in place at the time of hemodialysis initiation, and black patients spent, on average, approximately 40 more days on CVC compared with white patients.”
Continuing to Fall Short
With the study results demonstrating racial/ethnic and sex differences in AVF prevalence and more that 70% of participants failing to transition off CVC over 90 days, Dr. Arya says “we continue to fall significantly short” on main goals of the FFCL. “There is an urgent need for clinicians and policymakers to shift focus to minimizing catheter use for patients starting hemodialysis through CVC,” she adds. “Special outreach and intervention strategies focused on women and minority patients may be needed to facilitate quicker transition. Future work should focus on understanding the system level and process mechanisms behind the prolonged CVC use in the United States and re-evaluating strategies to decrease time on CVC, especially in these patient populations.”
