Systematic review of randomised controlled trials of sildenafil (Viagra®) in the treatment of male erectile dysfunction.

Background: Sildenafil (Viagra®), a new oral drug for the treatment of erectile dysfunction, was licensed for use across Europe in 1998. Aim: To examine the effectiveness and safety of sildenafil as an oral treatment for erectile dysfunction. Design of study: Systematic review and meta-analysis.
Setting: All published or unpublished randomised controlled trials comparing sildenafil with a placebo or alternative therapies. Method: Published studies were sought by computerised searches of electronic databases using the keywords ‘sildenafil’ and ‘Viagra’. A hand search was also done of the British Medical Journal, Lancet, Journal of the American
Medical Association, New England Journal of Medicine, British Journal of General Practice, Drug, Inpharma and Scrip. An assessment of quality of all identified studies and data extraction was undertaken independently by two researchers. Results were combined in a meta-analysis where appropriate, using RevMan version 3. Results: Twenty-one trials were identified. All trials showed a statistically significant improvement in erectile or sexual function in patients using sildenafil compared with a placebo. A meta-analysis of 16 trials reporting a global efficacy response showed that men were 3.57 (95% CI = 2.93–4.43) times as likely to have improved erections on sildenafil compared with those on a placebo. The number needed to treat to have one man with improved erections was two. The drug has a relatively safe side-effect profile. Conclusions: Available research shows that sildenafil is an effective treatment for male erectile dysfunction. Many trial participants had some baseline erectile function and it is probable that in clinical practice, where the erectile function tends to be more impaired, the number needed to treat may be higher.

Folate fortification : a case study of public health policy-making

Introducing Evidence Based Health Policy: Problems and Possibilities, Section 1: What is the Problem?, 1: Competing Rationalities: Evidence based Health Policy, 2: Beyond Two Communities, Section 2: What does Evidence Mean?, 3: Evidence based Medicine - The Medical Profession and Health Policy, 4: Mind The Gap: Assessing the Quality of Evidence for Public Health Problems, 5: Health Policy and Normative Analysis: Ethics, Evidence and Politics, 6: What is New in Health Information? Evidence for Health Consumers and Policy Making, 7: From Evidence based Medicine to Evidence based Public Health, Section 3: Policy Case Studies, 8: The Viagra Affair: Evidence as the Terrain for Competing Partners, 9: Folate Fortification: A Case Study of Public Health Policy-Making in a Food Regulation Setting, 10: The Supply and Safety of Blood and Blood Products - Evidence, Risk and Policy, 11: The Development of Nurse Practitioner Policy, 12: Creating Healthy Public Policy for Oral Health: How was the Evidence Used?, 13: Regulation of Traditional Chinese Medicine in Victoria, 14: The Victorian Primary Health Care Reforms: A Case Study of Evidence-based Policy Making, 15: Evidence-based Practice in the Australian Drug Policy Community, 16: Challenging the Evidence - Women's Health Policy in Australia, 17: Evidence and Aboriginal Health Policy, 18: The Limits to Technical Rationality in the Health Inequalities Policy Process, 19: Evidence-based policy: A Technocratic Wish in a Political World, Section 4: Is the transfer of evidence into policy possible?, 20: The Community Model of Research Transfer, 21: Getting Research Transfer into Policy and Practice in Maternity Care, 22: Improving the Research and Policy Partnership: An Agenda for Research Transfer and Governance, 23: Framing and Taming 'Wicked' Problems