NASHVILLE—Researchers who analyzed data from clinical trials of darbepoetin alfa in anemic non-dialysis CKD patients found that all patients experience variable hemoglobin (Hb) levels, although the degree of fluctuation may vary.

The findings highlight the difficulties in maintaining Hb within a narrow range when treating anemia in this patient population. The question to consider is what degree of Hb variability—within or outside target Hb values—is of clinical significance in this population, said lead investigator Anil K. Agarwal, MD, associate professor of clinical medicine and director of interventional nephrology at The Ohio State University Medical Center in Columbus.

Dr. Agarwal and his colleagues focused on data from four U.S-based clinical trials involving a total of 931 patients, 877 of whom were included in this analysis. In two studies, the target Hb range was 10-12 g/dL; in the other two, the target range was 11-13 g/dL.

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All studies had a 28-week evaluation period, during which most Hb measurements were within study-specified target ranges. The majority of patients, however, experienced some Hb fluctuations outside these ranges. Intra-patient Hb levels, on average, varied 0.6-0.9 g/dL from subjects’ overall mean value.

In addition, Dr. Agarwal’s group found that hospitalization due to an adverse event was associated with an increase in Hb variability. Dr. Agarwal hypothesized that the hospitalizations reflect more serious underlying comorbidities that contributed to greater Hb variability.

Higher baseline BMI and higher baseline albumin values were associated with lower variability. “These [factors] may represent a state of better nutrition and lower inflammation and would be consistent with the observation that low Hb variability is associated with positive outcomes,” Dr. Agarwal explained.