Erythropoietin Is Not a Cause of Access Thrombosis

Relation between level or change of hemoglobin and generic and disease-specific quality of life measures in hemodialysis

OBJECTIVE

We sought to examine the relation between meeting or exceeding the current minimum guideline for hemoglobin (11 g/dl) in dialysis patients and generic and disease-specific QOL scores at 1 year.

METHODS

In 438 incident hemodialysis patients from a national prospective cohort study, we used regression models to predict QOL score (all scaled 0-100) at 1 year using 6-month values of hemoglobin, adjusting for potential confounders.

RESULTS

Compared to values < 11 g/dl, hemoglobin > or = 11 g/dl at 6 months was associated with higher scores for the general domains of physical functioning, role physical, mental health, social functioning, and bodily pain at 1 year; cognitive function, diet restriction, and dialysis access dialysis-specific domain scores were also higher for these patients. Each 1 g/dl greater hemoglobin was also statistically significantly associated with higher QOL scores for most domains. In longitudinal analyses, most of the domains showed that, with each 1 g/dl increase in hemoglobin concentration from baseline to 6 months, QOL score increased significantly over the first year.

CONCLUSIONS

Hemodialysis patients who attain higher hemoglobin concentration at 6 months, especially > or = 11 g/dl, have better QOL at 1 year, with regard to important physical, mental, social, and cognitive domains.

Normalization of haemoglobin concentration with recombinant erythropoietin has minimal effect on blood haemostasis

BACKGROUND

Elevation of haemoglobin (Hb) with recombinant erythropoietin (rHuEpo) in patients with chronic renal failure has raised concern of increased risk of thromboembolic diseases. In this study, a substudy of the Scandinavian multicentre trial, we examined the influence on haemostatic parameters of normalization of Hb levels from subnormal levels in patients with chronic renal failure.

METHODS

Twenty-six patients, 17 males (before study start Hb 113+/-6 g/l) and nine females (Hb 111+/-8 g/l), with end-stage renal disease were included. Both dialysis and predialysis patients were included. After 3 months of rHuEpo therapy Hb levels reached 136+/-14 g/l for males and 128+/-13 g/l for females, and after 1 year 142+/-11 g/l and 126+/-14 g/l respectively. The increase in Hb was significant both at 3 months and 1 year, compared to baseline. At baseline, after 3 months and 1 year haemostatic and prothrombotic parameters were measured, including prothrombin complex test, activated partial thromboplastin time, platelet aggregation and retention, von Willebrand factor antigen, antithrombin, protein C, total and free protein S, activated protein C resistance, FV-Leiden mutation, D-dimers, plasminogen activator inhibitor-1 and prothrombin fragments 1+2 (PF 1+2).

RESULTS

The only statistically significant change was a transient decrease in total levels of protein S at 3 months from 131 to 120% (P=0.0093). The free and active form of protein S showed no significant change. After 1 year the difference was not seen.

CONCLUSIONS

Apart from a transient and clinically insignificant decrease in total protein S, we found no prothrombotic changes after normalization of Hb from subnormal levels. Our findings indicate that rHuEpo treatment may aim at normalizing Hb levels without significant effects on haemostatic parameters in patients with chronic renal failure compared to patients with subnormal Hb levels.

Elevated erythropoietin receptor and transforming growth factor-beta1 expression in stenotic arteriovenous fistulae used for hemodialysis

The issue of whether recombinant human erythropoietin (rhEPO) increases thrombosis of arteriovenous (AV) fistulae used for hemodialysis remains unclear. Thrombosis often occurs at stenotic segments of fistulae where there is marked intimal hyperplasia and extracellular matrix accumulation. Increased expression of transforming growth factor-beta1 (TGF-beta1) has been shown to be involved in the development of atherosclerotic lesions by promoting intimal hyperplasia and extracellular matrix accumulation. To clarify the role of rhEPO in the development of stenosis of AV fistulae, this study examined expression of the erythropoietin receptor (EPO-R), TGF-beta1, plasminogen activator inhibitor type 1 (PAI-1), cellular fibronectin containing an extra domain A (EDA+), and TGF-beta1 mRNA, and assessed in situ rhEPO binding in tissue specimens from seven cutaneous veins and eight patent and seven stenosed portions of AV fistulae of patients undergoing dialysis. Prominent intimal hyperplasia was evident in the stenosed segments. Significant elevation in expression of EPO-R and TGF-beta1 was noted in patent AV fistulae compared to the cutaneous veins. Significant enhancement of EPO-R and TGF-beta expression was detected in the stenotic fistulae. Fibronectin EDA+ and PAI-1 expression was increased in intimal hyperplasia compared to patent fistulae and cutaneous veins. Elevated EPO-R expression was further confirmed by in situ binding of biotin-labeled rhEPO in stenosed tissue specimens. It is hypothesized that increased rhEPO binding due to elevated EPO-R expression contributes to the development of AV fistula stenosis caused by intimal hyperplasia and extracellular matrix accumulation in response to increased TGF-beta1 expression in patients receiving hemodialysis.

The effects of normal as compared with low hematocrit values in patients with cardiac disease who are receiving hemodialysis and epoetin

BACKGROUND

In patients with end-stage renal disease, anemia develops as a result of erythropoietin deficiency, and recombinant human erythropoietin (epoetin) is prescribed to correct the anemia partially. We examined the risks and benefits of normalizing the hematocrit in patients with cardiac disease who were undergoing hemodialysis.

METHODS

We studied 1233 patients with clinical evidence of congestive heart failure or ischemic heart disease who were undergoing hemodialysis: 618 patients were assigned to receive increasing doses of epoetin to achieve and maintain a hematocrit of 42 percent, and 615 were assigned to receive doses of epoetin sufficient to maintain a hematocrit of 30 percent throughout the study. The median duration of treatment was 14 months. The primary end point was the length of time to death or a first nonfatal myocardial infarction.

RESULTS

After 29 months, there were 183 deaths and 19 first nonfatal myocardial infarctions among the patients in the normal-hematocrit group and 150 deaths and 14 nonfatal myocardial infarctions among those in the low-hematocrit group (risk ratio for the normal-hematocrit group as compared with the low-hematocrit group, 1.3; 95 percent confidence interval, 0.9 to 1.9). Although the difference in event-free survival between the two groups did not reach the prespecified statistical stopping boundary, the study was halted. The causes of death in the two groups were similar. The mortality rates decreased with increasing hematocrit values in both groups. The patients in the normal-hematocrit group had a decline in the adequacy of dialysis and received intravenous iron dextran more often than those in the low-hematocrit group.

CONCLUSIONS

In patients with clinically evident congestive heart failure or ischemic heart disease who are receiving hemodialysis, administration of epoetin to raise their hematocrit to 42 percent is not recommended.