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Homocysteine and C-reactive protein levels in haemodialysis patients
E Koulouridis1, M Tzilianos, A Katsarou
1Nephrology Department, General Hospital of Corfu, Greece. koulef@otenet.gr
Insights
Hyperhomocysteinemia is common in dialysis patients and linked to cardiovascular disease. Oral folate supplementation normalized homocysteine levels only in patients with higher levels, while C-reactive protein predicted short-term survival.
Area of Science:
- Nephrology
- Cardiovascular Medicine
- Nutritional Science
Background:
- Hyperhomocysteinemia is prevalent in hemodialysis patients and a known risk factor for cardiovascular disease in end-stage renal failure.
- Vitamin supplementation, including folate, is proposed to correct hyperhomocysteinemia, but its efficacy in normalizing homocysteine levels in dialysis patients is debated.
Purpose of the Study:
- To investigate homocysteine levels in hemodialysis patients compared to healthy controls.
- To assess the impact of oral folate supplementation on homocysteine levels in these patients.
- To analyze the relationship between homocysteine, C-reactive protein, and short-term survival.
Main Methods:
- Measured homocysteine, folate, vitamin B12, and C-reactive protein (CRP) in 53 hemodialysis patients before and after dialysis.
- Compared patient homocysteine levels to 30 healthy blood donors.
- Administered oral folate (10 mg/day) for four weeks, re-evaluating homocysteine and folate levels.
- Monitored patient survival for 18 months, analyzing its correlation with homocysteine and CRP.
Main Results:
- Hemodialysis patients had fourfold higher homocysteine levels than controls.
- Homocysteine levels decreased post-dialysis, while folate, vitamin B12, and CRP increased.
- Patients with coronary heart disease showed higher homocysteine levels.
- Folate supplementation did not change overall homocysteine levels but decreased them in patients with levels >24 micromol/L.
- C-reactive protein, not homocysteine, significantly predicted short-term survival.
Conclusions:
- Hemodialysis is associated with significantly elevated homocysteine levels, inversely correlated with folate.
- Oral folate supplementation effectively increases folate but only reduces homocysteine in a subset of patients with marked hyperhomocysteinemia.
- C-reactive protein is a significant predictor of short-term survival in hemodialysis patients, whereas homocysteine is not.
Background:
Mild to moderate hyperhomocysteinemia is very common among patients undergoing haemodialysis. There is sufficient evidence that hyperhomocysteinemia is an independent risk factor for cardiovascular and or atheromatous disease in end stage renal failure patients. Vitamin supplementation such as vitamin B6, B12 or folate has been proposed to correct this metabolic disturbance and it is to be proved if this intervention benefit these patients, but there is no agreement whether oral folate supplementation is capable to normalize homocysteine levels in end stage renal failure patients.
Methods:
In 53 patients, undergoing haemodialysis, homocysteine levels (Hcy), folate, vitamin B12, ferritin and C-reactive protein (CRP) were estimated before and after dialysis, without folate supplementation. Thirty voluntary blood donors were used as controls to compare homocysteine levels. After four weeks of oral folate supplementation (10 mg/24 hours) the levels of homocysteine, serum folate and intra-erythrocyte folate were estimated again. Eighteen months later the survival rate of our patients was recorded and analyzed in relation to Hcy and CRP levels.
Results:
The results showed that haemodialysis patients exhibited, almost, fourfold higher homocysteine levels than controls (27.39 +/- 11.54 vs 7.38 +/- 3.5, t = -8.2, p = 0.000000). Folate levels, vitamin B12 and CRP increase significantly after haemodialysis where as homocysteine levels decrease (Hcy1 vs. Hcy2: z = 2.08, p = 0.03). Fourteen (14) patients suffered from coronary heart disease (CHD) and they exhibited the higher levels of homocysteine (Hcy1 vs. CHD: z = -3.4, p = 0.0006). All estimations performed revealed a negative correlation between homocysteine levels and plasma or intra-erythrocyte folate. No other variable exhibited any significant influence upon homocysteine levels. After folate supplementation homocysteine levels in the whole number of patients were unchanged (Hcy(before) vs. Hcy(after): 27.39 +/- 11.54 vs. 26.95 +/- 8.22, z = 0.3, p = 0.7, NS). When patients with homocysteine levels higher than 24 micromol/L were selected, a significant decrease was observed (34.77 +/- 9.32 vs. 30.0 +/- 8.05, z = 2.09, p = 0.02). Forty-two patients were treated with erythropoietin for their anemia and we found a positive correlation between C-reactive protein levels and rhu-Epo dose (CRP vs. Epo: r = 0.45, p = 0.002). Homocysteine levels did not exhibit any significant influence upon short-term survival (U = -0.37, p = 0.3, NS) where as CRP levels exhibit a significant influence upon short-term survival (U = 2.15, p = 0.005).
Conclusions:
Homocysteine levels in haemodialysis patients are fourfold higher than healthy controls. Folate, vitamin B12 and CRP increases significantly after dialysis. Patients with coronary heart disease exhibit the highest levels of homocysteine. The homocysteine levels are inversely related with the folate levels. The exogenous folate supplementation increase the serum folate levels but decreases homocysteine only in patients with higher than mild hyperhomocysteinemia. Hcy doesn't exert any significant effect upon the short-term survival of the haemodialysis patients but CRP level is a god predictor of the short-term survival of these patients.