Abstract
Introduction
Erectile dysfunction may affect 30-50% of men aged 40-70 years, with age, smoking and obesity being the main risk factors, although 20% of cases have psychological causes.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of phosphodiesterase inhibitors in men with erectile dysfunction of any cause? What are the effects of phosphodiesterase inhibitors on erectile dysfunction in men with diabetes, with cardiovascular disease, with spinal cord injury, and with prostate cancer or prostatectomy? What are the effects of drug treatments other than phosphodiesterase inhibitors in men with erectile dysfunction of any cause? What are the effects of devices, psychological/behavioural treatments, and alternative treatments in men with erectile dysfunction of any cause? We searched: Medline, Embase, The Cochrane Library and other important databases up to August 2005 (BMJ Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
Results
We found 63 systematic reviews, RCTs or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
Conclusions
In this systematic review we present information relating to the effectiveness and safety of the following interventions: alprostadil (intracavernosal, intraurethral, topical) apomorphine, cognitive behavioural therapy, ginseng, papaverine, papaverine plus phentolamine (bimix), papaverine plus phentolamine plus alprostadil (trimix), penile prostheses, phosphodiesterase inhibitors (sildenafil, tadalafil, vardenafil), psychosexual counselling, vacuum devices, and yohimbine.
Key Points
Erectile dysfunction may affect 30-50% of men aged 40-70 years, with age, smoking and obesity being the main risk factors, although 20% of cases have psychological causes.
Sildenafil improves erections and increases the likelihood of successful intercourse overall and in men with diabetes mellitus, heart disease, spinal cord injury, prostate cancer or after radical prostatectomy.
Tadalafil and vardenafil are also effective overall and in men with diabetes. Vardenafil may be effective after prostatectomy, but few studies have been found.
CAUTION: sildenafil, tadalafil and vardenafil are contraindicated in men who are taking nitrates as combined treatment has been associated with severe hypotension and death.
Intracavernosal alprostadil improves erections compared with placebo, intraurethral alprostadil and intracavernosal papaverine, but can cause penile pain in up to 40% of men.
Intracavernosal alprostadil may be as effective as sildenafil and bimix, while topical alprostadil may also be effective.
Adding phentoloamine to intracavernosal papaverine (bimix) may increase effectiveness compared with papaverine alone, and adding alprostadil to bimix (trimix) may be more effective again. However, papaverine injections may cause altered liver function, and penile bruising and fibrosis.
Sublingual apomorphine, ginseng and yohimbine may increase successful erections and intercourse compared with placebo.
Vacuum devices may be as effective as intracavernosal alprostadil at increasing rigidity, but less effective for orgasm, and may block ejaculation.
There is consensus that penile prostheses may be beneficial, but they can cause infections and are only used if less invasive treatments have failed.
Psychosexual counselling and cognitive behavioural therapy may improve sexual functioning in men with psychological erectile dysfunction, but few good quality studies have been found.
About this condition
Definition
Erectile dysfunction is defined as the persistent inability to obtain or maintain sufficient rigidity of the penis to allow satisfactory sexual performance. The term erectile dysfunction has largely replaced the term "impotence". For the purposes of this review we included only men with normal testosterone and gonadotrophin levels, who could gain an erection while asleep. We also included men with comorbid conditions such as cardiovascular disorders, prostate cancer, diabetes, and spinal cord injury. We excluded men with drug induced sexual dysfunction. Because the cause of erectile dysfunction in men with cardiovascular disease is unclear (the disease or treatment drugs), we included them.
Incidence/ Prevalence
Cross-sectional epidemiological studies from around the world reveal that 30-50% of men aged 40-70 years report some degree of erectile dysfunction. About 150 million men worldwide are unable to achieve and maintain an erection adequate for satisfactory sexual intercourse. Age is the variable most strongly associated with erectile dysfunction; between the ages of 40 to 70 years, the incidence of moderate erectile dysfunction doubles from 17% to 34%, whereas that of severe erectile dysfunction triples from 5% to 15%.
Aetiology/ Risk factors
About 80% of cases are believed to have an organic cause, the rest being psychogenic in origin. Most cases of erectile dysfunction are believed to be multifactorial and secondary to disease, stress, trauma (such as spinal cord injury, pelvic and prostate surgery), or drug adverse effects that interfere with the coordinated psychological, neurological, endocrine, vascular, and muscular factors necessary for normal erections. Risk factors include increasing age, smoking, and obesity. The prevalence of erectile dysfunction also increases in people with diabetes mellitus, hypertension, heart disease, anxiety, and depression.
Prognosis
We found no good evidence on prognosis in untreated organic erectile dysfunction.
Aims of intervention
To restore satisfactory erections, with minimal adverse effects of treatment.
Outcomes
Self and partner reports of satisfaction and sexual function, quality of life, objective tests of penile rigidity, time to take effect, duration of effect, ease of usage, mortality, and adverse effects of treatment.
Methods
Clinical Evidence search and appraisal August 2005. We searched for RCTs comparing each listed intervention versus placebo, no treatment, or each other and have included all studies of sufficient quality. We excluded studies where less than 80% of men had normal hormone levels. We only included studies that considered clinical end points. Where several RCTs were found, we have only included studies that used clinical end points (such as successful attempts at intercourse) as outcome measures. We have performed a GRADE evaluation of the quality of evidence for interventions included in this review (see table ).
Table.
GRADE evaluation of interventions for erectile dysfunction
| Important outcomes | Improvement in sexual function, adverse effects | ||||||||
| Number of studies (participants) | Outcome | Comparison | Type of evidence | Quality | Consistency | Directness | Effect size | GRADE | Comment |
| What are the effects of phosphodiesterase inhibitors in men with erectile dysfunction of any cause? | |||||||||
| 29 (at least 2283 men) | Improvement in sexual function | Sildenafil v placebo in men with erectile dysfunction of any cause | 4 | −1 | 0 | 0 | 0 | Moderate | Quality point deducted for for uncertainty about methods of randomisation and allocation concealment |
| 1 (54) | Improvement in sexual function | Sildenafil v intracavernosal alprostadil in men with erectile dysfunction of any cause | 4 | −1 | 0 | 0 | 0 | Moderate | Quality point deducted for sparse data |
| 16 (2827) | Improvement in sexual function | Tadalafil v placebo in men with erectile dysfunction of any cause | 4 | −2 | 0 | −2 | 0 | Very low | Quality points deducted for uncertainty about methods of randomisation and whether allocation concealmentwas performed, and for lack of homogeneity in study design and outcome assessments. Directness points deducted for heterogeneity in aetiology of erectile dysfunction and age of population |
| 3 (1729) | Improvement in sexual function | Vardenafil v placebo in menwith erectile dysfunction of any cause | 4 | −1 | 0 | −1 | 0 | Low | Quality point deducted for uncertainty about quality of studies. Directness point deducted for inclusion of previous responders to treatment |
| What are the effects of phosphodiesterase inhibitors on erectile dysfunction in men with diabetes? | |||||||||
| 18 (1820) | Improvement in sexual function | Sildenafil v placebo in men with diabetes | 4 | −1 | 0 | 0 | +1 | High | Quality point deducted for subgroup analysis. Effect size point added for RR greater than 2 but less than 5 |
| 1 (216) | Improvement in sexual function | Tadalafil v placebo in men with diabetes | 4 | 0 | 0 | 0 | 0 | High | |
| 1 (452) | Improvement in sexual function | Vardenafil v placebo in men with diabetes | 4 | 0 | 0 | 0 | 0 | High | |
| What are the effects of phosphodiesterase inhibitors on erectile dysfunction in men with cardiovascular disease? | |||||||||
| At least 2 RCTs (739) | Improvement in sexual function | Sildenafil v placebo in men with heart disease | 4 | 0 | 0 | 0 | 0 | High | |
| 24 (664) | Adverse effects | Sildenafil v placebo in men with heart disease | 4 | 0 | 0 | 0 | 0 | High | |
| What are the effects of phosphodiesterase inhibitors on erectile dysfunction in men with spinal cord injury? | |||||||||
| 1 (205) | Improvement in sexual function | Sildenafil v placebo in men with spinal cord injury | 4 | 0 | 0 | 0 | +2 | High | Effect size points added for RR greater than 5 |
| What are the effects of phosphodiesterase inhibitors on erectile dysfunction in men with prostate cancer or prostatectomy? | |||||||||
| 2 (176) | Improvement in sexual function | Sildenafil v placebo in men after radical prostatectomy or prostate cancer | 4 | −2 | 0 | 0 | +1 | Moderate | Quality points deducted for sparse data and for subgroup analysis. Effect size point added for RR less than 5 but greater than 2 |
| 1 (440) | Improvement in sexual function | Vardenafil v placebo in men after prostatectomy | 4 | −1 | 0 | −1 | 0 | Low | Quality point deducted for for uncertainty about quality of studies. Directness point deducted for inclusion of previous responders to treatment |
| What are the effects of drug treatments other than phosphodiesterase inhibitors in men with erectile dysfunction of any cause? | |||||||||
| 3 (1828) | Improvement in sexual function | Intraurethral alprostadil v placebo in men with erectile dysfunction of any cause | 4 | −1 | 0 | −1 | +2 | High | Quality point deducted for for not stating methods of randomisation and whether allocation concealment was performed. Directness point deducted for pre-selecting treatment responders affecting generalisability to clinical practice. Effect size points added for OR greater than 5 |
| 1 (270) | Improvement in sexual function | Intraurethral alprostadil v placebo in men after radical prostatectomy | 4 | −1 | 0 | 0 | 0 | Moderate | Quality point deducted for not reporting method of randomisation and allocation concealment |
| 3 (274) | Improvement in sexual function | Intraurethral alprostadil v intracavernosal alprostadil in men with erectile dysfunction of any cause | 4 | −2 | 0 | −1 | 0 | Very low | Quality points deducted for open label study and for uncertaintity about randomisation and whether allocation concealment was performed . Directness point deducted for pre-selecting treatment responders affecting generalisability to clinical practice |
| 3 (1345) | Improvement in sexual function | Apomorphine v placebo in men with erectile dysfunction of any cause | 4 | −1 | 0 | 0 | 0 | Moderate | Quality point deducted for not reporting methods of randomisation and allocation concealment |
| 2 (82) | Improvement in sexual function | Topical alprostadil v placebo in men with erectile dysfunction of any cause | 4 | −2 | 0 | 0 | 0 | Low | Quality points deducted for sparse data, and for not reporting methods of randomisation and allocation concealment |
| 1 (40) | Improvement in sexual function | Papaverine v papaverine plus phentolamine (bimix) in men with with erectile dysfunction of any cause | 4 | −1 | 0 | 0 | 0 | Moderate | Quality point deducted for sparse data |
| 1 (30) | Improvement in sexual function | Papaverine plus phentolamine (bimix) v placebo in men with with erectile dysfunction of any cause | 4 | −1 | 0 | −1 | 0 | Low | Quality point deducted for sparse data. Directness point deducted for no direct statistical comparison between groups |
| 2 (356) | Improvement in sexual function | Intracavernosal alprostadil v placebo in men with erectile dysfunction of any cause | 4 | −3 | 0 | 0 | 0 | Very low | Quality points deducted for incomplete reporting of results, and for methodological weaknesses (randomisation/allocation concealment, subjective assessment of outcome and unblinded assessment of outcome) |
| 3 (235) | Improvement in sexual function | Intracavernosal alprostadil v papaverine in men with erectile dysfunction of any cause | 4 | −3 | 0 | 0 | 0 | Very low | Quality points deducted for methodological weaknesses (uncertainty about methods of randomisation and allocation concealment, subjective and unblinded assessment of outcome) |
| 2 (142) | Improvement in sexual function | Intracavernosal alprostadil v papaverine plus phentolamine (bimix) in men with erectile dysfunction of any cause | 4 | −3 | 0 | 0 | 0 | Very low | Quality points deducted for sparse data, and for methodological weaknesses (uncertainty about methods of randomisation and allocation concealment, subjective and unblinded assessment of outcome) |
| 2 (114) | Improvement in sexual function | Intracavernosal alprostadil v alprostadil plus papaverine plus phentolamine (trimix) in men with erectile dysfunction of any cause | 4 | −3 | 0 | 0 | 0 | Very low | Quality points deducted for sparse data, and for methodological weaknesses (uncertainty about methods of randomisation and allocation concealment, subjective and unblinded assessment of outcome) |
| 1 (50) | Improvement in sexual function | Intracavernosal alprostadil v vacuum devices in men with erectile dysfunction of any cause | 4 | −3 | 0 | −1 | 0 | Very low | Quality points deducted for sparse data, and for methodological weaknesses (randomisation/allocation concealment, subjective assessment of outcome). Directness point deducted for not using validated outcome assessments |
| What are the effects of devices in men with erectile dysfunction of any cause? | |||||||||
| 1 (45) | Improvement in sexual function | Vacuum devices plus psychosexual therapy v psychosexual therapy in men with erectile dysfunction of any cause | 4 | −3 | 0 | −1 | 0 | Very low | Quality points deducted for sparse data, and for methodological weaknesses (lack of blinding, subjective assessment of outcome). Directness point deducted for not using validated outcome assessments |
| What are the effects of psychological/behavioural treatments in men with erectile dysfunction of any cause? | |||||||||
| 2 (90) | Improvement in sexual function | Psychosexual counselling v waiting list control in men with erectile dysfunction of any cause | 4 | −3 | 0 | 0 | 0 | Very low | Quality points deducted for sparse data, incomplete reporting of results and for methodological weaknesses (uncertainities about methods of randomisaton and /allocation concealment |
| 1 (69) | Improvement in sexual function | Psychosexual counselling vinterpersonal therapy in men with erectile dysfunction of any cause | 4 | −2 | 0 | 0 | 0 | Low | Quality points deducted for sparse data, and for methodological weaknesses (uncertainities about methods of randomisaton and /allocation concealment |
| What are the effects of alternative treatments in men with erectile dysfunction of any cause? | |||||||||
| 1 (45) | Improvement in sexual function | Ginseng v placebo in men with erectile dysfunction of any cause | 4 | −1 | 0 | 0 | 0 | Moderate | Quality point deducted for sparse data |
| 8 (448) | Improvement in sexual function | Yohimbine v placebo in men with with erectile dysfunction of any cause | 4 | −3 | 0 | −2 | +1 | Very low | Quality points deducted for methodological weaknesses (uncertainity about method of randomisation, lack of homogeneity in study design and outcome assessments). Directness points deducted for heterogeneity in aetiology of erectile dysfunction and age of population, and for method of assessment |
Type of evidence: 4 = RCT; 2 = Observational Consistency: similarity of results across studies Directness: generalisability of population or outcomes Effect size: based on relative risk or odds ratio
Glossary
- Ecchymosis
The skin discoloration caused by the escape of blood into the tissues from ruptured blood vessels.
- Global Assessment Questionnaire
A self administered questionnaire that allows men to rate improvement in erectile function.
- Global Efficacy Question
Asks, “Did the treatment you have been taking over the past 4 weeks improve your erections?” This question is answered with a “yes” or “no”. In some trials, responses are scored on a 7 point scale ranging from “no improvement” to “intense improvement”.
- High-quality evidence
Further research is very unlikely to change our confidence in the estimate of effect.
- International Index of Erectile Function (IIEF) questions 3 and 4
The questions have been validated for assessing the effects of treatments for men with erectile dysfunction. They ask, “over the past 4 weeks, when you have attempted sexual intercourse, how often were you able to penetrate (enter) your partner?”, and “Over the past 4 weeks, during sexual intercourse, how often were you able to maintain your erection after you have penetrated (entered) your partner?” Each question is answered on a 6 point scale of 0–5.
- Low-quality evidence
Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
- Moderate-quality evidence
Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
- Priapism
Prolonged, and often painful, erections of the penis in the absence of sexual desire that can last for several hours to days. Prompt treatment to relieve the erection and prevent scarring is recommended if the erection does not subside in 4 hours.
- Sexual Encounter Profile (SEP) questions 2 and 3
This is a diary maintained by men after each sexual attempt consisting of a series of yes/no questions regarding specific aspects of each encounter. Question 2 asks, “Were you able to insert your penis into your partner's vagina?” and question 3 asks, “Did your erection last long enough for you to complete intercourse with ejaculation?”
- Very low-quality evidence
Any estimate of effect is very uncertain.
Disclaimer
The information contained in this publication is intended for medical professionals. Categories presented in Clinical Evidence indicate a judgement about the strength of the evidence available to our contributors prior to publication and the relevant importance of benefit and harms. We rely on our contributors to confirm the accuracy of the information presented and to adhere to describe accepted practices. Readers should be aware that professionals in the field may have different opinions. Because of this and regular advances in medical research we strongly recommend that readers' independently verify specified treatments and drugs including manufacturers' guidance. Also, the categories do not indicate whether a particular treatment is generally appropriate or whether it is suitable for a particular individual. Ultimately it is the readers' responsibility to make their own professional judgements, so to appropriately advise and treat their patients.To the fullest extent permitted by law, BMJ Publishing Group Limited and its editors are not responsible for any losses, injury or damage caused to any person or property (including under contract, by negligence, products liability or otherwise) whether they be direct or indirect, special, incidental or consequential, resulting from the application of the information in this publication.
Contributor Information
Prathap Tharyan, Department Of Psychiatry, Christian Medical College, Tamil Nadu, India.
Ganesh Gopalakrishanan, Department Of Psychiatry, Christian Medical College, Tamil Nadu, India.
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