Can rescaling dose of dialysis to body surface area in the HEMO study explain the different responses to dose in women versus men?

Clin J Am Soc Nephrol. 2010 Sep;5(9):1628-36. doi: 10.2215/CJN.02350310. Epub 2010 Jul 1.


Background and objectives: In the Hemodialysis (HEMO) Study, the lower death rate in women but not in men assigned to the higher dose (Kt/V) could have resulted from use of "V" as the normalizing factor, since women have a lower anthropometric V per unit of surface area (V/SA) than men.

Design, setting, participants, & measurements: The effect of Kt/V on mortality was re-examined after normalizing for surface area and expressing dose as surface area normalized standard Kt/V (SAn-stdKt/V).

Results: Both men and women in the high-dose group received approximately 16% more dialysis (when expressed as SAn-stdKt/V) than the controls. SAn-stdKt/V clustered into three levels: 2.14/wk for conventional dose women, 2.44/wk for conventional dose men or 2.46/wk for high-dose women, and 2.80/wk for high-dose men. V/SA was associated with the effect of dose assignment on the risk of death; above 20 L/m(2), the mortality hazard ratio = 1.23 (0.99 to 1.53); below 20 L/m(2), hazard ratio = 0.78 (0.65 to 0.95), P = 0.002. Within gender, V/SA did not modify the effect of dose on mortality.

Conclusions: When normalized to body surface area rather than V, the dose of dialysis in women in the HEMO Study was substantially lower than in men. The lowest surface-area-normalized dose was received by women randomized to the conventional dose arm, possibly explaining the sex-specific response to dialysis dose. Results are consistent with the hypothesis that when dialysis dose is expressed as Kt/V, women, due to their lower V/SA ratio, require a higher amount than men.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Body Surface Area*
  • Female
  • Humans
  • Kinetics
  • Male
  • Models, Biological*
  • Multicenter Studies as Topic
  • Proportional Hazards Models
  • Randomized Controlled Trials as Topic
  • Renal Dialysis / mortality*
  • Research Design
  • Risk Assessment
  • Risk Factors
  • Sex Factors
  • Urea / metabolism


  • Urea