Short-term effects of nocturnal haemodialysis on carnitine metabolism

Nephrol Dial Transplant. 2006 Sep;21(9):2637-41. doi: 10.1093/ndt/gfl312. Epub 2006 Jul 5.


Background: Functional carnitine deficiency [as indicated by an abnormal acyl-carnitine/free-carnitine (AC:FC) ratio] is commonly seen in patients with end-stage renal disease (ESRD), resulting in significant clinical detriments including anaemia, cardiomyopathy and muscle weakness. Nocturnal haemodialysis (NHD) (5-6 sessions per week, 8 h per treatment) has been reported to reverse several surrogate markers of uraemia. Conversely, as a consequence of increased dialysis dose, NHD may have the potential to aggravate plasma nutrient deficiencies. Our objective was to determine the effects of NHD on plasma free-carnitine levels and carnitine metabolism.

Methods: We conducted an observational cohort study with a before and after design. Nine ESRD patients (age: 47 +/- 3; mean +/- SEM) were studied. Routine biochemical, haemodynamic and carnitine metabolic products were analysed at baseline while on conventional haemodialysis and 2 months post-conversion to NHD. Free-carnitine and total-carnitine levels were generated by colorimetric assays. The difference between total- and free-carnitine concentrations was estimated to be the acyl-carnitine level. Paired t-test was used to ascertain statistical significance.

Results: After conversion to NHD, there was a significant increase in urea clearance in all patients. Plasma free-carnitine levels fell from 26.54 +/- 2.99 to 15.6 +/- 2.34 micromol/l (P < 000.1). A similar reduction in plasma acyl-carnitine levels was observed (from 13.22 +/- 1.34 to 6.24 +/- 1.20 micromol/l (P < 0.001)). The AC:FC ratio improved from 0.51 +/- 0.03 to 0.39 +/- 0.03 (P < 0.005) (Normal < 0.25).

Conclusion: NHD is associated with an improvement in AC:FC ratio. Further research is needed to examine the longitudinal clinical impact of this metabolic correction and to examine whether this effect is sustained.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Biological Factors
  • Carnitine / analogs & derivatives
  • Carnitine / blood*
  • Circadian Rhythm / physiology*
  • Colorimetry
  • Disease Progression
  • Female
  • Follow-Up Studies
  • Humans
  • Kidney Failure, Chronic / blood
  • Kidney Failure, Chronic / therapy*
  • Male
  • Middle Aged
  • Prognosis
  • Prospective Studies
  • Renal Dialysis*
  • Time Factors


  • Biological Factors
  • acylcarnitine
  • Carnitine