Impact of recombinant erythropoietin on sexual function in hemodialysis patients

Interventions for treating sexual dysfunction in patients with chronic kidney disease

BACKGROUND

Sexual dysfunction is very common in patients with chronic kidney disease (CKD), but it is still significantly understudied. Treatment options exist but concerns have been raised relating to their efficacy and safety in CKD.

OBJECTIVES

We assessed the benefits and harms of existing interventions for treatment of sexual dysfunction in patients with CKD.

SEARCH STRATEGY

In October 2010 we searched the Cochrane Renal Group's specialised register, CENTRAL (The Cochrane Library, issue 10), MEDLINE (from 1966) and EMBASE (from 1980).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs of any pharmacological and non-pharmacological interventions used to treat sexual dysfunction in male and female CKD patients (predialysis, dialysis and kidney transplant) were included.

DATA COLLECTION AND ANALYSIS

Two authors independently selected eligible studies, extracted data and assessed study quality. Disagreements were resolved in consultation with an arbitrator. Treatment effects were summarised as risk ratios (RR), mean differences (MD) or standardised mean difference (SMD) with 95% confidence intervals (CI) using a random-effects model.

MAIN RESULTS

Fifteen studies (8 parallel, 7 crossover; 352 patients) were included. Only one study enrolled women. Studies evaluated the effects of phosphodiesterase-5 inhibitors (PDE5i), zinc, vitamin E, vitamin D or bromocriptine compared to placebo. PDE5i significantly increased the overall International Index of Erectile Function-5 (IIEF-5) score (2 studies, 101 patients, MD 10.65, 95% CI 5.34 to 15.96), all its individual domains and the complete 15-item IIEF tool (1 study, 41 patients, MD 2.64, 95% CI 1.32 to 3.96). End of treatment testosterone levels were not significantly increased by addition of zinc to dialysate (2 studies, 22 patients, MD 0.21 ng/mL, 95% CI -2.14 to 2.55) but oral zinc improved end of treatment testosterone levels (1 study, 20 patients, SMD 1.62, 95% CI 0.58 to 2.66). There was no difference in plasma luteinizing and follicle-stimulating hormone levels at the end of the study period with zinc therapy. Only sparse data were available for vitamin E, bromocriptine and dihydroxycholecalciferol in CKD patients and there were no studies of intracavernous injections, transurethral injections, mechanical devices or psychosexual therapies in people with CKD.

AUTHORS' CONCLUSIONS

PDE5i and zinc are promising interventions for treating sexual dysfunction in men with CKD. Evidence supporting their routine use in CKD patients is limited. There is an unmet need for studying interventions for both male and female sexual dysfunction in CKD, considering the significant disease burden.

Projecting the United States ESRD population: Issues regarding treatment of patients with ESRD

In 2001, there were 406,081 patients who received treatment for end-stage renal disease (ESRD), increasing by 4.2% since 2000. The number of patients with ESRD has grown consistently over the past decade, with the greatest rate of growth occurring among patients older than 75 years of age, and patients with comorbidities such as diabetes mellitus and hypertension. Current projections indicate that the population of patients with ESRD may reach more than 2 million by 2030. The overall mortality rate has fallen by 10% since 1988, with the greatest decline among patients incident to dialysis, and an increase among patients receiving dialysis for greater than five years. While the rate of hospitalization for ESRD patients has remained relatively constant, recent improvements in mortality are temporally associated with a greater proportion of patients achieving adequate benchmarks of care in dialytic processes, such as anemia correction and dose of dialysis. The ESRD program consumes 6.4% of the Medicare budget. On a per-patient per month basis, Medicare costs have risen between 1991 and 2001. While payments fell slightly during 1998 and 1999 because of changes in Medicare policies, more recent years have seen an upswing in total expenditures, presumably related to use of injectables not included in the composite rate. Continued growth in the number of new patients reaching ESRD, as well as improved mortality rates of ESRD patients, are both contributing to the current rise and projected epidemic of ESRD over the next 25 years. The current public health strategy of identification of patients with early kidney disease to slow their progression to ESRD, in addition to aggressive treatment strategies to minimize the morbidity and mortality of patients with ESRD, is essential toward affecting the growth and health of this population.

Long-term effects of recombinant human erythropoietin therapy on growth hormone secretion in uremic patients undergoing peritoneal dialysis

Recombinant human erythropoietin (rhEPO) is being successfully used for the treatment of uremic anemia. Short-term studies have proved that correction of anemia with rhEPO therapy is accompanied by several changes in growth hormone (GH) secretion in uremic patients. The present study aimed to assess the influence of long-term rhEPO therapy on baseline and stimulated GH concentrations in a group of uremic patients undergoing continuous ambulatory peritoneal dialysis (CAPD). Seven well-nourished and clinically stable CAPD patients were studied. Ten normal subjects were studied as controls. GH responses to direct pituitary stimulation with GH-releasing hormone (GHRH) (100 microg intravenously [i.v.]) and indirect hypothalamic stimulation with insulin-induced hypoglycemia (0.1 U/kg body weight i.v.) and clonidine (0.15 mg/m2 orally), were assessed before and after 3, 6, and 12 months of subcutaneously administered rhEPO therapy. After rhEPO administration, an increase of the hemoglobin concentration was observed in all patients and maintained at about 12 g/dL throughout the study period. rhEPO therapy did not induce any significant change in baseline concentrations of GH and insulin-like growth factor I. Correction of the anemia was accompanied by a clear increase in the area under the curve (AUC) and the area above the baseline (AAB) of GH secretion in response to GHRH stimulation. These changes were statistically significant after 3 and 6 months of therapy, although at 12 months no significant differences in relation to pretreatment values could be observed. rhEPO treatment was associated with a progressive decrement in the GH AUC and AAB in response to hypoglycemic challenge, reaching statistically significant values at months 6 and 12. On the other hand, compared with the control group, GH responses to clonidine were blunted at the start of the study in CAPD patients, and rhEPO therapy was not accompanied by any modification. In conclusion, long-term treatment with rhEPO in CAPD patients is associated with complex and profound effects on somatotrope cell function, characterized by diverse effects on GH responses to stimuli that release GH through different mechanisms. Some of these rhEPO-induced alterations in somatotrope function are dependent on the duration of treatment.

Secular trends in recombinant erythropoietin therapy among the U.S. hemodialysis population: 1990-1996

BACKGROUND

Chronic anemia is a major cause of morbidity among the end-stage renal disease (ESRD) population. Recombinant erythropoietin (rHuEPO) has been recognized as a major advance in the treatment of anemia among the ESRD population. This study examines the secular trends in the use of and response to rHuEPO therapy among severely, moderately and mildly anemic hemodialysis patients.

METHODS

We designed a cohort analytic study using seven years of claims data. The study population comprised all facility-based adult hemodialysis patients receiving rHuEPO therapy, who were initially reimbursed by Medicare in each of the first quarter of the calendar years 1990 through 1996 (N = 64,957).

RESULTS

Between 1990 and 1996, the mean rHuEPO dose increased by 139% for the patient cohorts with a first observed hematocrit < 0.25, 122% for the 0.25 to 0.29 cohorts, and 107% for the > or = 0.30 cohorts, and produced a 0.02 to 0.03 increase in achieved hematocrit (A-Hct) over this time. Dosing of rHuEPO did not appear to be influenced by patient or provider characteristics, although African-Americans, the elderly, non-diabetics and persons receiving dialysis in a non-profit facility had a larger percent change in hematocrit compared to their counterparts (P < 0.001).

CONCLUSIONS

The results of the clinical use of rHuEPO seven years after FDA approval found in the general ESRD hemodialysis population have not equaled the results obtained in the initial clinical trials. Overall, our findings suggest that substantial increases in rHuEPO dose provided to anemic patients have resulted in only modest increases in hematocrit in the seven years since rHuEPO's introduction. Resistance to rHuEPO, prior rHuEPO treatment, inadequate use of supplemental iron, and policy and financial incentives may explain this finding.

Function of endocrine organs in hemodialyzed patients of long-term erythropoietin therapy

Endocrine abnormalities in patients with chronic renal failure are well documented. The present study aimed to assess the influence of long-term erythropoietin (EPO) therapy on endocrine abnormalities in hemodialyzed patients. Two groups of hemodialyzed patients, each of which comprised 17 subjects, were examined. The first group was treated by EPO (EPO group) while the second one did not receive this hormone (No-EPO group). A complete biochemical and hormonal check-up was performed before and at the 3, 6, 9, and 12 month points of the study period. Normal values for the estimated parameters were obtained in appropriately selected sex- and age-matched healthy subjects. After EPO therapy, an increase of the hematocrit value from 21.8 +/- 0.9 to 32.6 +/- 0.9% was observed, which was accompanied by a significant decline of plasma ferritin and saturation of transferrin. In patients of the No-EPO group, a significant although less marked rise of the hematocrit value (21.4 +/- 0.4 to 24.2 +/- 0.6%) was also noticed. EPO therapy did not change plasma levels of electrolytes (Na, K, Ca, inorganic phosphate), osteocalcin, creatinine, glucose, and alkaline phosphatase as well as plasma concentrations of calcium-related hormones (PTH, calcitonin, 1,25[OH]2D3), vasopressin, and triiodothyronine. EPO treatment induced a significant decrease in somatotropin, prolactin, follitropin, lutropin, ACTH, cortisol, plasma renin activity, aldosterone, noradrenaline, adrenaline, dopamine, glucagon, pancreatic polypeptide, and gastrin plasma levels and an increase in plasma insulin, estradiol, testosterone, atrial natriuretic peptide, thyrotropin, and thyroxine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adapting the dialysis unit to increased hematocrit levels

Recombinant human erythropoietin (epoetin) therapy had a significant impact on the practice of nephrology before its widespread use in the dialysis arena. Since then, a number of long-term studies have provided physicians with parameters for optimizing therapeutic response and patient outcomes with epoetin therapy. Fears of accelerated hypertension syndromes or increased fistula clotting are recognized as largely unfounded. There is a marked improvement in well-being, as measured by both subjective and objective parameters, as the level of anemia is reduced. Fortunately, epoetin was recognized early as essential therapy in patients on dialysis and thus was reimbursed by the Health Care Financing Administration (HCFA) and other payers, albeit through various methods of payment. Why is it, then, that hematocrit levels are still averaging approximately 30%? Perhaps the basic concern that all practitioners share is the potential for increased morbidity at "higher" hematocrit levels. Increased access clotting was not reported in the recently completed Epogen (Epoetin alfa; Amgen Inc, Thousand Oaks, CA) phase IV postmarketing study. Needle size, however, needs to be considered, because higher blood flow rates accompanied by higher hematocrit levels may lead to increased hemolysis. The venous needle size is especially important in patients who experience large weight gains. It is important to keep these issues in mind as one decides on an appropriate hematocrit level for a given patient. Hull and Eschbach reviewed postdialysis data from patients with naturally occurring high hematocrit levels and found no major changes in hematocrit level, thus alleviating the concern of significant postdialysis inspissation as a common cause for fistula clotting.

Increased growth hormone response to growth hormone releasing hormone induced by erythropoietin in uraemic patients

This study was designed to assess the response of growth hormone (GH) to growth hormone releasing hormone (GHRH) and the possible interaction of acutely administered recombinant human erythropoietin (rhEPO) on GH response to GHRH in a group of uraemic patients. Eight patients on maintenance haemodialysis, not previously treated with rhEPO, and six healthy controls were tested with GHRH (100 micrograms i.v. in bolus), and with GHRH (100 micrograms i.v. in bolus) plus rhEPO (40 U/kg in constant infusion for 30 min) on different days. GHRH injection provoked a GH release in five out of eight uraemic patients; the overall mean response did not differ significantly from the GH response obtained in controls (P = 0.30). Erythropoietin infusion significantly increased GH release after GHRH (P less than 0.01 at 15, 30, 45, 60 min after GHRH injection) in uraemic patients; in controls, on the contrary, stimulation with GHRH plus rhEPO did not induce a greater increase of GH release compared with that observed after GHRH alone (mean GH peak 37.66 +/- 7.68 mU/l after GHRH; and 38.0 +/- 9.18 mU/l after GHRH plus rhEPO; P greater than 0.5). In this study acutely administered rhEPO significantly potentiated the GH response to GHRH in uraemic patients whereas the same effect was not demonstrable in subjects with normal renal function.