Q) suPAR, a new screening tool for chronic kidney disease, has gotten a lot of press recently. My practice is interested in implementing it, but we can’t find information on how to obtain it. Is it commercially available yet? How can we order it? And importantly for our patients, do insurance plans cover it?
Research has been ongoing regarding biomarkers that could identify those at risk for chronic kidney disease (CKD) long before loss of renal function is apparent. A recently published study suggests that the circulating protein, soluble urokinase-type plasminogen activator receptor (suPAR), may be such a biomarker.
In a study of 3,683 subjects (ages 20 to 90) undergoing cardiac catheterization, and a further evaluation of 347 subjects in the Women’s Interagency HIV Study, Hayek et al found that elevated levels of suPAR were independently associated with CKD and with accelerated loss of renal function. At five-year follow-up, 24% of the 1,335 subjects with an initial estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m2 had developed CKD. Risk for progression to CKD was about 41% in those with a baseline suPAR level ≥ 3,040 ng/mL, compared to 12% in those with lower baseline suPAR levels.1 Thus, the cutoff for high versus low risk appears to be 3,040 ng/mL.
Hayek and associates are not the first or the only investigators studying the connection between suPAR and kidney disease. Evolving research has suggested suPAR may be an initiating factor in the development of focal segmental glomerulosclerosis (FSGS).2 However, a recent study did not support this association.3
Currently, in the United States, laboratory testing for suPAR is available only for research purposes and has not been approved by the FDA for direct patient care.4 While more research is needed with different cohorts, there is much excitement in the field of nephrology regarding the potential role of suPAR as a biomarker for predicting CKD. —CS
Cindy Smith, DNP, APRN, CNN-NP, FNP-BC
Renal Consultants, PLLC, South Charleston, West Virgina
References
1. Hayek SS, Sever S, Ko Y-A, et al. Soluble urokinase receptor and chronic kidney disease. N Engl J Med. 2015;373:1916-1925.
2. Spinale JM, Mariani LH, Kapoor S, et al. A reassessment of soluble urokinase-type plasminogen activator receptor in glomerular disease. Kidney Int. 2015;87(3):564-574.
3. Wei C, El Hindi S, Li J, et al. Circulating urokinase receptor as a cause of focal segmental glomerulosclerosis.Nature Med. 2011;17: 952-960.
4. Rush University Medical Center. Early warning found for chronic kidney disease: common protein in blood rises months or years before disease develops [news release]. November 5, 2015. www.rush.edu/news/press-releases/early-warning-found-chronic-kidney-disease. Accessed April 11, 2016.