Objectives: To evaluate the relationship between hemoglobin (Hb) level and quality of life (QOL) in anemic patients with non-dialysis chronic kidney disease receiving epoetin alfa.
Patients and methods: A post-hoc analysis using data from a multicenter, open-label, prospective study of epoetin alfa for anemia in patients with chronic kidney disease not on dialysis was conducted. The relationship between Hb and QOL was analyzed using correlation and longitudinal analyses, the latter adjusting for sample selection bias. The Linear Analog Scale Assessment (LASA) and the Kidney Disease Questionnaire (KDQ) subscales were used to measure QOL. The impact of an incremental 1 g/dL increase in Hb level on LASA and KDQ scores was determined using an incremental analysis.
Results: A total of 1183 and 1044 patients formed the study populations for the LASA and KDQ analyses, respectively. There was a positive and significant relationship between Hb levels and QOL (p < 0.05). Using non-linear regression analysis, we characterized the sigmoid-shape of the relationship between Hb levels and QOL scores. Hemoglobin change was a statistically significant determinant of QOL improvement for both LASA and KDQ scales (p < 0.05). The model predicted that, based on a 2 unit change in Hb, the greatest incremental QOL improvement per unit of Hb increase occurred when Hb was in the range of 11 to 12 g/dL.
Conclusions: This study demonstrates that, beyond the well-known relationship between Hb increases and QOL improvements, the maximal incremental gain in QOL occurred when Hb reached 11 to 12 g/dL. This suggests that treating anemic patients with non-dialysis chronic kidney disease until their Hb level reaches 12 g/dL will result in the greatest QOL improvement per Hb unit increase. The analyses were conducted based on an open-label study of epoetin alfa and could be further validated using a randomized, controlled trial, comparing incremental gains in QOL associated with treatment initiation at varying levels of Hb across arms.