Medical Research: What is the background for this study?
Dr. Weichhart: Impairment of high-density lipoprotein (HDL) function has been associated with cardiovascular events in patients with kidney failure on hemodialysis. The protein composition of HDLs is altered in these patients presumably compromising the cardioprotective effects of HDLs. In an earlier study we found that two proteins in particular, namely Serum Amyloid A (SAA) and Surfactant Protein B (SP-B), are significantly raised in the HDL of dialysis patients, and these also contribute towards HDL losing its protective effect. In the current study we have now developed an novel test that can quickly and directly measure the SAA and SP-B bound to HDL.
Medical Research: What are the main findings?
Dr. Weichhart: We have measured the concentrations of HDL-associated SAA and SP-B in 1152 patients with type 2 diabetes mellitus on hemodialysis. High levels of SAA in the HDL were associated with an increased occurrence of heart attacks, while high levels of SP-B in the HDL acted as a marker for a generally increased risk of mortality. Importantly, these effects were independent of the HDL-cholesterol levels
Medical Research: What should clinicians and patients take away from your report?
Dr. Weichhart: High HDL levels are generally regarded as the best type to have and are believed to protect against cardiovascular diseases such as heart attacks and strokes. Clinical practice currently only measures the amount of cholesterol in the HDL (known as the HDL-C) and the protective effect against future cardiovascular disease is derived from this. Our research together with other studies shows, however, that in many chronic diseases such as coronary heart disease, diabetes mellitus or in patients receiving dialysis, the quantity of HDL-C in the blood cannot be used as a prognostic marker. As a result, new methods are needed in order to better estimate the risk of cardiovascular disease. The new test may in future allow a much more precise risk prediction for cardiovascular diseases in order to decisively improve the overall prognosis.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Weichhart: The laboratory test needs to be evaluated in other patient collectives in order to confirm the results.
Chantal Kopecky, Bernd Genser, Christiane Drechsler, Vera Krane, Christopher C. Kaltenecker, Markus Hengstschläger, Winfried März, Christoph Wanner, Marcus D. Säemann, and Thomas Weichhart
CJASN CJN.06560714; published ahead of print November 25, 2014, doi:10.2215/CJN.06560714