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Current management of erectile dysfunction

Geoffrey Hackett
MD MRCPG MRCPI
GP
Consultant
in Urology
West Midlands
President of British Society of Sexual Medicine

Currently there are no endorsed UK guidelines for the assessment and management of erectile dysfunction (ED). The National Institute for Health and Clinical Excellence (NICE) requires assessment to be initiated by the Department of Health (DH) rather than clinicians, and so far no assessment for ED has been called for. The DH Schedule 2 guidance is not evidence-based and merely offers advice on conditions that will be covered on NHS prescription and the classification of "severe distress".(2) Unfortunately, the regulations have not been reviewed in line with clinical developments since 1999. Schedule 2 suggests that: "It is anticipated that one tablet per week will be appropriate for the majority of patients. Where there is clinical need more medication can be prescribed and this should be on NHS prescription." Luckily the British Society of Sexual Medicine is developing evidence-based guidance.
The European Urology Association guidelines on erectile dysfunction suggest a detailed clinical history to assess important risk factors for:(3)

  • Cardiovascular disease.
  • Hypertension.
  • Hyperlipidaemia.
  • Diabetes.
  • Late-onset hypogonadism.
  • Depression.

The standard recommended investigations are:

  • Fasting blood glucose.
  • Lipid profile.
  • Morning total testosterone (ideally free testosterone if available) and prolactin.
  • Prostate or thyroid assessment if relevant symptoms are present.

Such assessments will create a number of therapeutic dilemmas for the primary healthcare professional.

Borderline diabetes
Patients will be detected with fasting blood glucose levels in the borderline range of 6-7mmol/l, which is not diagnostic of type 2 diabetes. ED is associated with metabolic syndrome, and in 20% of cases ED predates the diagnosis.(4,5) There is good evidence that lifestyle modification will improve erectile function within three months and will provide positive reinforcement of the benefits of early intervention.(6) Many patients will develop clinical type 2 diabetes and, at this stage, will qualify for NHS prescriptions for ED under Schedule 2. From the patient's point of view, it is important that the correct message is given to the patient and that borderline levels are followed up. A number of complaints against GPs have arisen when patients have been made to pay for private drugs when they have clearly been diabetic for some time and the GP has failed to monitor them adequately. In such cases it is the duty of the GP, not the patient, to understand the regulations.(2)

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Hyperlipidaemia
Screening for ED will uncover a number of men with mildly elevated hyperlipidaemia who would not normally fit the 20% 10-year indication for prescription of a statin. We now know, however, that ED is an important predictor for CHD developing in 5-10 years and that the risk of a patient developing ED is directly related to total cholesterol and inversely related to HDL levels.(7) The process of ED in these patients is endothelial dysfunction occurring in the penile vasculature, in arteries 60% of the diameter of the coronary vessels.(8,9) An important parallel could be drawn with the treatment of depression, where we consider the quality of life of the patient, not just the likely risk of suicide or premature death.
The important implication for these patients is that recent studies suggest that both lifestyle modification  and particularly statins can significantly improve the ED within three months.(6,10) Even if the GP elects not to prescribe a statin himself, the patient should be offered the opportunity to self-medicate with a statin at around £3 per month compared with a PDE5 inhibitor (PDE5I) at £20-40 per month, depending on the desired frequency. Recent evidence suggests that three months' treatment to target with a statin plus diet would be most appropriate for these patients, reserving the PDE5I to be added in patients who do not respond. Statins have recently been found to be an effective salvage strategy in patients with cardiovascular disease who do not adequately respond to a PDE5I alone. Clearly the patient needs to be involved in all aspects of the discussion.

Late-onset hypogonadism
Screening for ED will reveal up to 15% of patients with morning testosterone levels below the normal range on two separate occasions. At least 30% of people with type 2 diabetes have low levels. An important study in the US found that 38% of men over 50 routinely attending GPs had low testosterone levels (below 10.4nmol/l) and that the odds ratio for such patients having diabetes, hypertension, hyperlipidaemia and obesity was doubled.(11) Studies are required to assess whether intervention will lower this risk, but the prospects for future research is exciting. As a general rule, symptoms of hypogonadism, such as tiredness, low libido, muscle aches, poor concentration (frequently wrongly diagnosed and treated as depression) occur below 8nmol/l, whereas levels above 14nmol/l may be required for optimal sexual function.
The dilemma is whether to treat with testosterone, a PDE5I, or both. To complicate matters, other vascular risk factors may be present. The patient will expect that the doctor will treat the "abnormality" that has been found and not merely provide a long-term prescription for an on-demand drug to treat a symptom, privately at the patient's expense. It is also widely accepted that low testosterone is a common reason for low response to PDE5Is. Testosterone therapy, particularly with transdermal gels, is well tolerated, and the patient may well see an improvement in libido and ejaculatory function as well as erection. Any improvement in general wellbeing would be greatly appreciated, as well as the fact that it will be covered by NHS prescription, an issue certainly likely to influence patient choice. Around 30% of patients can be expected to respond to testosterone alone, usually within four to six weeks. A PDE5I could then be added to nonresponders. It is currently suggested that a prostate-specific antigen test (PSA) and digital rectal examination are performed before commencing testosterone and that PSA, full blood count and testosterone levels are checked regularly.

Possible health benefits of PDE5Is
Recent research suggests possible long-term benefits for PDE5Is in endothelial function, peripheral vascular disease, Raynaud's disease, lower urinary tract symptoms, diabetic neuropathy and pulmonary hypertension (a licensed indication).(12,13) Current large-scale studies are ongoing in each of these therapy areas.

Conclusion
Questioning about ED should now be regarded as routine in the management of men's health. Important, potentially treatable medical conditions will be detected by motivated nurses, with potential benefit to the patient and his family.

References

  1. Thompson IM, et al. Erectile dysfunction and subsequent cardiovascular disease. JAMA 2005;294:2996-3002.
  2. Central Office of Information. Health impotence consultation document. Number 0274. 7 May 1999.
  3. Wespes E, et al. EAU guidelines on erectile dysfunction: an update. Eur Urol 2006;49:806-15.
  4. Matfin G, Jawa A, Fonseca VA. Erectile dysfunction: interrelationship with the metabolic syndrome. Curr Diab Rep 2005;5:64-9.
  5. Fonseca V, et al. Impact of diabetes mellitus on the severity of erectile dysfunction and response to treatment: analysis of data from tadalafil clinical trials. Diabetologia 2004;47:1914-23.
  6. Esposito K, et al. Effect of lifestyle changes on erectile dysfunction in obese men: a randomized controlled trial. JAMA 2004;291:2978-84.
  7. Nikoobakht M, Nasseh H, Pourkasmaee M. The relationship between lipid profile and erectile dysfunction. Int J Impot Res 2005;17:523-6.
  8. Kirby M, et al. Is erectile dysfunction a marker for cardiovascular disease?  Int J Clin Pract 2001;55:614-8.
  9. Solomon H, Man JW, Jackson G. Erectile dysfunction and the cardiovascular patient: endothelial dysfunction is the common denominator. Heart 2003;89:251-3.
  10. Saltzman E, Guay AT. Improvement in erectile function in men with organic ED by lowering of total cholesterol. J Urol 2004;172:255-8.
  11. Mulligan T, et al. Prevalence of hypogonadism in males aged at least 45 years: the HIM study. Int J Clin Pract 2006;60:762-9.
  12. Rosano GM, et al. Chronic treatment with tadalafil improves endothelial function in men with increased cardiovascular risk. Eur Urol 2005;47:214-20.
  13. Hackett G. PDE5 inhibitors and diabetic neuropathy. Int J Clin Pract 2006;60:1123-6.