A Systematic Review Assessing the Economic Impact of Sildenafil Citrate (Viagra®) in the Treatment of Erectile Dysfunction
Corresponding Author: Amber L. Martin, BS, United BioSource Corporation, 430 Bedford St., Suite 300, Lexington, MA 02420, USA. Tel: +1-781-960-0230; Fax: +1-781-761-0147; E-mail: firstname.lastname@example.org
Sildenafil was the first oral phosphodiesterase type 5 (PDE5) inhibitor introduced as primary therapy for erectile dysfunction (ED). In the 7 years following its market launch, sildenafil was prescribed by more than 750,000 physicians to more than 23 million men worldwide. To date, few studies have evaluated the economic impact of sildenafil in treating ED.
To evaluate the cost-effectiveness and impact of sildenafil on health care costs for patients with ED in multiple countries.
Main Outcomes Measures.
Economic outcomes including cost, cost-effectiveness, cost of illness, cost consequence, resource use, productivity, work loss, and willingness to pay (WTP) were investigated.
Using keywords related to economic outcomes and sildenafil, we systematically searched literature published between July 2001 and July 2011 using MEDLINE and EMBASE. Included articles pertained to costs, WTP, and economic evaluations.
In the last 10 years, 12 studies assessed economic outcomes associated with sildenafil for ED. Most studies were conducted in the United States and the United Kingdom, with one study identified in Canada and one from Mexico. Six studies evaluated cost of illness, cost consequence, or cost of care, and four studies evaluated WTP or drug pricing by country in the United States and the United Kingdom. In the United States and the United Kingdom, costs to health care systems have increased with demand for treatment. Cost analyses suggested that sildenafil would lower direct costs compared with other PDE5 inhibitors. US and UK studies found that patients exhibited WTP for sildenafil. The two cost-effectiveness models we identified examined ED sub-groups, those with spinal cord injury and those with diabetes or hypertension. These models indicated favorable cost-effectiveness profiles for sildenafil compared with other active-treatment options in both Mexico and Canada.
The relative value of sildenafil vs. surgically implanted prosthetic devices and other PDE5 inhibitors, is underscored by patients' WTP, and cost-effectiveness in ED patients with comorbidities.