Department of Internal Medicine, Division of Nephrology, and Department of Urology, Selçuk University School of Medicine, and Istanbul School of Medicine, Istanbul University, Turkey
![]() |
Abstract |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Patients and methods. In this study, 35 male HD patients (mean age 48±12 years) and 15 male CAPD patients (mean age 44±12 years) were included. In the baseline period, haemoglobin, serum urea, and albumin, Kt/V, several hormonal parameters, Beck depression scale, and penile Doppler blood flow, (peak systolic velocity after intracavernous papaverine administration) were measured. The international index of erectile function (IIEF) form was used to evaluate erectile dysfunction. Sildenafil was given to patients with erectile dysfunction at a dose of 50100 mg/day twice a week.
Results. The percentage of erectile dysfunction was similar between patients on HD (71%) and those on CAPD (80%). Patients with erectile dysfunction were significantly older and had lower free-testosterone serum levels and penile blood flow than those without. In linear regression analysis for baseline IIEF score, penile blood flow was the only independent variable associated with erectile dysfunction. IIEF score increased to a similar extent after sildenafil treatment in both HD patients (from 8.10±5.54 to 21.70±9.61, P<0.001) and CAPD patients (from 9.90±3.87 to 21.60±10.18, P=0.011). Changes in IIEF scores after sildenafil treatment were associated with baseline penile blood flow as an independent variable by linear regression analysis. Adverse events observed during sildenafil treatment were dyspepsia in two patients and headache in one patient.
Conclusion. The rate of erectile dysfunction is high in dialysis patients. Penile blood flow is the most important factor for predicting both the development of erectile dysfunction and the response to sildenafil therapy in such patients. Oral sildenafil is an effective, reliable, well-tolerated treatment for uraemic patients with erectile dysfunction.
Keywords: CAPD; erectile dysfunction; haemodialysis; penile blood flow; sildenafil
![]() |
Introduction |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
The aim of this study was to evaluate the factors involved in ED and the efficacy and the safety of sildenafil in the treatment of ED in haemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) patients.
![]() |
Patients and methods |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
|
Initially, sildenafil (Viagra®) was recommended to and accepted by 30 (20 HD and 11 CAPD) patients. Sildenafil (50 mg/day) was administered to the patients with ED twice a week. At the end of 4 weeks, the dosage of sildenafil was increased to 100 mg if there was no response to 50 mg (n=12 patients). Side-effects were recorded.
![]() |
Statistics |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Data are shown as median and 2575th percentiles. Numerical values under or above the median levels represents the values below the 10th percentile and above the 90th percentile. Numerical variables with normal distribution were compared with paired and non-paired Student's t-tests and when variables had non-normal distribution, MannWhitney U or Wilcoxon test were used. Correlations between two numerical variables were sought with Pearson bivariate correlation test and Spearman rho test when appropriate. For non-numerical variables, Chi-square test was used. For 2*2 contingency tables, Yates correction was made. When assumptions were violated in 2*2 tables, Fisher's exact test was used. Factors that affect baseline IIEF score and increase in IIEF score after sildenafil treatment were examined with multiple linear regression analysis. Independent variables were age, penile blood flow, free-testosterone, and Beck depression scale. P value <0.05 was accepted as significant.
![]() |
Results |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
The percentage of ED was quite high (37 of the 50 patients, 74%) and similar between patients on HD (25 of the 35 patients, 71%) and CAPD (12 of the 15 patients, 80%) according to criteria derived from IIEF score mentioned above. On comparing patients with and without ED, time on dialysis, serum urea, albumin, haemoglobin, prolactin, FSH, LH, iPTH levels, and results of the Beck scale were not different. Patients with ED were significantly older and free-testosterone levels were significantly decreased in patients with ED as compared to patients without ED. Penile blood flow was significantly decreased in ED patients as compared to without ED (Table 2).
|
After detection of ED in dialysis patients, sildenafil treatment was given to 20 HD and 10 CAPD patients. Response was defined as IIEF score above 26 after sildenafil treatment. Twelve of the 20 HD patients and six of the 10 CAPD patients had responded to the therapy. None of the patients who did not respond to 50 mg sildenafil responded to 100 mg/day sildenafil treatment. Response rate (60%) was found to be same between study groups. Patients not responding to sildenafil treatment (n=12) had significantly lower penile blood flow than the responding patients (23±14 cm/s vs 37±9 cm/s, P=0.003). However, no differences in age, time on dialysis, haemoglobin, and serum free-testosterone levels were found between responding and non-responding patients.
IIEF score increased after sildenafil treatment in both HD (from 8.10±5.54 to 21.70±9.61, P<0.001) and CAPD (from 9.90±3.87 to 21.60±10.18, P= 0.011). Increase in IIEF scores was similar between HD and CAPD (13.6±8.4 vs 11.7±8.5 respectively, P=NS) (Figure 1). Change in IIEF score was correlated with penile blood flow (r=0.66, P<0.001). In multiple linear regression analysis for changes in IIEF scores after sildenafil treatment, penile Doppler was found as an independent variable (Figure 2
).
|
|
Regarding safety of the therapy, the adverse events observed during sildenafil treatment were dyspepsia in two patients and headache in one patient. These side-effects were short-lasting and did not require any treatment. None of the patients had hypotensive episode in their HD sessions during the study period.
![]() |
Discussion |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Numerous factors such as hormonal disturbances, peripheral neuropathy, autonomic dysfunction, peripheral vascular disease, psychological stress, medication, and uraemic milieu have been implicated in the development of this disorder [1,11]. Anxiety and depression are commonly present in dialysis patients. It was reported that patients with ED were more depressed and anxious, and sub-clinical depression may be underestimated as a contributory factor [9,12]. However, Procci et al. [1] reported no association of depression with sexual dysfunction. In addition, no difference in Beck depression scale was found between patients with and those without ED in our study.
Changes in endocrine functions due to disturbances in hypothalamicpituitarytesticular function such as lower free-testosterone, higher LH and FSH, and elevated prolactin are well known in patients with uraemia [13]. However, the role of these disturbances on development of ED is incompletely understood. No improvement of libido or potency with administration of testosterone has been reported [14]. Lawrence et al. [15] reported that depot testosterone treatment fully restored sexual function in only three of the 27 male dialysis patients in their study. In our study, the only difference in hormonal parameters between patients with and without ED found was a decrease in serum free-testosterone levels in patients with ED. However, it was not an independent variable in linear regression analysis for IIEF score, and this finding was consistent with previous reports [14,15].
Ischaemic heart diseases and peripheral vascular lesions due to accelerated atherosclerosis have been reported to be much more common in patients with uraemia. A peripheral vascular lesion obstructing penile arterial blood flow was also proposed as a contributing factor to ED in this group of patients [16]. In our study, the most important factor on development of ED was penile blood flow in dialysis patients. However, resolution of ED after renal transplantation in some HD patients has been reported [17]. In these patients, peripheral arterial obstruction may not be a major factor in the development of ED. Small-vessel circulatory dysfunction due to uraemic autonomic dysfunction which improves after transplantation may be main culprit in decreased penile blood flow [18].
Sildenafil treatment as a first-line therapy has been successfully used for treating ED in non-uraemic population. However, no study specifically addressed the issue of efficacy and safety of this drug on ED in patients with chronic renal failure, except for a few preliminary reports [5,6]. In our study, sildenafil therapy was found to be effective in ED of patients on dialysis. Response rate was found to be 60% in both HD and CAPD group. In addition, increase in IIEF scores were similar between HD and CAPD. It has been reported that sildenafil treatment was also effective and safe in diabetic men with ED [19]. In our study, no differences in response rate and similar increase in IIEF scores were found between diabetic and non-diabetic patients. However, the small sample size of diabetic patients treated precludes a definite conclusion. There is need for further study to address the efficacy of sildenafil treatment in diabetic patients with chronic uraemia.
In terms of safety, reported incidence of adverse events in non-uraemic population was low and symptoms were usually mild. The studies in men with ischaemic heart disease and hypertension sildenafil did not cause an increase in either MI or other serious cardiovascular events compared to placebo [20]. Safety for patients with uraemia is unclear. Some preliminary studies report that the drug could be utilized safely in dialysis patients if proper precautions, like not combining it with nitrates and not using it after recent coronary artery events, are taken. In our study, few mild side-effects were observed during sildenafil treatment, which suggests that sildenafil treatment is safe in uraemic men with ED.
In conclusion, ED percentage is very high in HD and CAPD patients. Penile blood flow status is the most important factor for predicting both the development of ED and response to sildenafil therapy in dialysis patients. Oral sildenafil is an effective, reliable, well-tolerated treatment for uraemic patients with ED, and should be the drug of first choice if there is no contraindication.
![]() |
Notes |
---|
![]() |
References |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|