© 2006 ELI LILLY CANADA JOURNAL COMPILATION © 2 0 0 6 B J U I N T E R N A T I O N A L | 9 8 , 6 2 3 – 6 2 9 | doi:10.1111/j.1464-410X.2006.06384.x 623 Original Article PREFERENCES FOR PDE5 INHIBITORS LEE et al. Physician-rated patient preference and patient- and partner-rated preference for tadalafil or sildenafil citrate: results from the Canadian ‘Treatment of Erectile Dysfunction’ observational study JAY LEE, PETER POMMERVILLE*, GERALD BROCK†, ROBERT GAGNON‡, PRAVINSAGAR MEHTA¶, MICHOKE KRISDAPHONGS§, MELANIE CHAN∞, JOHN CHAN∞ and RUTH DICKSON∞ Rockyview General Hospital, Department of Surgery, Division of Urology, University of Calgary, Alberta, *Can-Med Clinical Research Inc., Victoria, British Columbia, †Department of Surgery, Division of Urology, University of Western Ontario, St. Joseph’s Health Care and Hospital, London, Ontario, ‡Clinique de Médecine Familiale de Clermont, Quebec, ¶Department of Family Medicine, University of Manitoba, Winnipeg, Family Physician, Laxmi Centre, Winnipeg, Manitoba, §Conception Bay Medical Clinic, Conception Bay South, NL, and °Eli Lilly Canada, Scarborough, Ontario, Canada Accepted for publication 19 April 2006 tadalafil or sildenafil to the alternative drug were invited to participate in the study. The study duration was 4–12 weeks. At visit 1 (baseline), patient background information was collected. At visit 2, physicians answered the physician-rated patient-treatment preference questionnaire, patients answered the treatment preference question (TPQ) and the global assessment question (GAQ), and partners answered the partner TPQ. RESULTS The TED study was conducted at 266 sites across Canada and involved 2425 patients who used the allowed study medications, and 295 sexual partners who attended clinic visits. More than 98% of patients completed the study. Responses to the preference questionnaires showed that physician-rated patient preference, patient preference, and partner preference had a similar pattern preference, with a significantly higher proportion preferring tadalafil over sildenafil regardless of the change in treatment (i.e. sildenafil to tadalafil or tadalafil to sildenafil). Responses to the GAQ showed that nearly 90% of the patients who took either PDE5i said that the treatment had improved erections. CONCLUSIONS TED is the first study to assess physician- based ratings of patient preference, patient preference, and partner preference for tadalafil or sildenafil in a routine clinical practice settings. Most participants preferred tadalafil over sildenafil. Understanding the underlying reasons influencing the preference might improve patient compliance and satisfaction with treatment. KEYWORDS erectile dysfunction, phosphodiesterase type 5 inhibitors, preference, sildenafil, tadalafil OBJECTIVE To determine physician-based ratings of patient preference, patient preference, partner preference and physician-based assessment of the reasons for patient preference for tadalafil or sildenafil citrate (sildenafil) as a treatment for erectile dysfunction (ED) in routine clinical practice. Phosphodiesterase type 5 inhibitors (PDE5i) are effective and well-tolerated therapies for ED, but patient and partner preferences for these treatments might be determined by many factors, both medical and nonmedical. PATIENTS AND METHODS The Treatment of ED (TED) observational trial was a multicentre study conducted in Canada to determine patient and partner preferences for the PDE5i tadalafil or sildenafil in routine clinical practice. Patients who planned to change treatment from INTRODUCTION Erectile dysfunction (ED) is a chronic, age- related condition that affects > 150 million men worldwide [1]. It is estimated that 2–3 million Canadians have ED [2]. The number of men with ED in North America is projected to increase by 77% from 1995 to 2025, to approximately 21 million [1]. Many men with ED experience distress, depressive symptoms, reduced self-esteem, and/or diminished quality of life, while many sexual partners feel responsible for the problem or experience their own sexual dysfunction [3–10]. The first-line therapy for most men with ED is treatment with an orally administered phosphodiesterase type 5 inhibitor (PDE5i), e.g. sildenafil citrate, tadalafil or vardenafil HCl. These medications are effective, well tolerated and safe in men with ED of diverse causes [11–13]. Factors that might influence treatment preference for one ED medication over another include efficacy, tolerability and safety, as well as the perceived success and negative outcomes of therapy, cost, convenience reliability, partner preference, and naturalness [14,15]. To evaluate treatment preferences between sildenafil and tadalafil, and examine reasons for the preference, we conducted a prospective naturalistic study of men with ED who changed treatment from sildenafil to tadalafil (the sildenafil-tadalafil group) or from tadalafil to sildenafil (the tadalafil- sildenafil group) in routine clinical practice. PATIENTS AND METHODS The Treatment of ED (TED) was a multicentre, non-interventional, observational study conducted at 266 sites across Canada; > 95%