A 6 month, prospective, observational study of PDE5 inhibitor treatment persistence and adherence in Latin American men with erectile dysfunction

Abstract

Objectives:

To assess persistence/adherence rates of phosphodiesterase type-5 inhibitor (PDE5I) on-demand dosing in Latin American men with erectile dysfunction (ED), and explore patient characteristics and treatment factors that may be predictive for PDE5I persistence and adherence.

Methods:

Men from Brazil, Mexico, and Venezuela with ED who were naïve to PDE5Is were prescribed sildenafil, tadalafil, vardenafil, or lodenafil on-demand dosing and asked to provide information about PDE5I use at baseline and at 1, 3, and 6 months. Patients were persistent if they used ≥1 dose during the 4 week period prior to each evaluation. Patients were adherent if they complied with dosing instructions during most recent dose. Main outcome measures included Persistence and Adherence Questionnaire (PAQ), Partner Relationship Questionnaire (PRQ), Self-Esteem and Relationship (SEAR) Questionnaire, and International Index of Erectile Function (IIEF). Multivariate logistic regression was used to identify factors associated with persistence and adherence.

Results:

A total of 511 men were enrolled; most had mild to moderate ED (77.1%); 317 patients (62.0%) were prescribed tadalafil, 116 (22.7%) sildenafil, 75 (14.7%) vardenafil, and 3 (0.6%) lodenafil (not further analyzed). A total of 340 patients (66.5%) were ‘persistent’ at 6 months; 345 (67.5%) were ‘adherent’. Persistence and adherence were associated with age, education level, and ED duration. Reasons for non-persistence included medication cost and lack of efficacy. Study limitations included its design, brief observation period, its bias observed toward tadalafil selection; its dependence on patient self-reporting, limited number of factors that were analyzed for persistence/adherence association, its small number of participating patients and Latin American countries, and inherent differences in PDE5I preference and medical practices.

Conclusion:

Approximately two-thirds of PDE5I-naïve, Latin American men with ED were persistent and adherent after 6 months of therapy. Factors like education level, ED severity, and ED duration were associated with persistence and adherence; additional study is warranted to investigate the predictive value of these factors.

Keywords::

• Adherence
• Erectile dysfunction
• Persistence
• Sildenafil
• Tadalafil
• Vardenafil

Transparency

Declaration of funding

Eli Lilly and Company supported the study in its entirety. The sponsor, Eli Lilly and Company, was responsible for design and conduct of the study, for monitoring the study, and for verification and analysis of the data. All authors contributed to the writing and review process and approved the final manuscript.

Declaration of financial/other relationships

L.A.R. and S.S. are minor stock shareholders and full-time employees of Eli Lilly and Company. E.R.-A. has been a speaker and advisor for, and has received research support from: Lilly, Pfizer, Johnson & Johnson, Bayer, and Morepharma. L.B. is a speaker and advisor for Lilly. C.C. has been an advisor for Eli Lilly and Company, is a speaker for Bayer, GlaxoSmithKline, and Lilly, and is a principal investigator for Allergan, Amgen, Lilly, and Pfizer.

CMRO peer reviewers may have received honoraria for their review work. The peer reviewers on this manuscript have disclosed that they have no relevant financial relationships.

Acknowledgments

The authors thank the principal investigators and their clinical staff as well as the many patients who generously agreed to participate in this clinical trial.

List of study investigators: Carmita Abdo – São Paulo, Brazil; Luis Benavides – Clinica Valentina Canabal, Lara, Venezuela; Leonardo Borregales – Centro Medico de Caracas, Caracas, Venezuela; Carlos E Cairoli – Hospital São Lucas da Pontificia Universidade, Porto Alegre, Brazil; David Calvo – Mexico; Roman Carvajal – Jalisco, Mexico; Sergio Corona – Colima, Mexico; Francisco Cortes – Hospital Dr. Angelleaño, Jalisco, Mexico; Ronaldo Damião – Hospital Universitário Pedro Ernesto, Rio de Janeiro, Brazil; Adrian Diaz – Torre Medica Churubusco, Mexico, Mexico; Fernando N Facio Jr. – Hospital de Base, São José do Rio Preto, Brazil; Geraldo E Faria – Instituto de Urologia e Nefrologia de Rio Claro, Rio Claro, Brazil; Jose Flores – Clinica de Merida, Yucatan, Mexico; Rodolfo Galeana – Torre CCEMYD, Jalisco, Mexico; Bernardo Garcia – Jalisco, Mexico; Vicente Garcia – Centro de Especialidades Medicas, Guadalajara/Jalisco, Mexico; Sidney Glina – Hospital Ipiranga, São Paulo, Brazil; Ariel Gonzelez – Michoacan, Mexico; Carlos Gonzales – Especialidades Medicas de Occidente, Jalisco, Mexico; Francisco Lizarraga – Centro Medico Puerta de Hierro, Jalisco, Mexico; Rodolfo Matheus – Clinica ‘El Avila,’ Distrito Federal, Venezuela; Ernesto Mendoza – Jalisco, Mexico; Francisco Molina – Jalisco, Mexico; Gabriel Munoz – Jalisco, Mexico; Luis Novelo – Unidad de Diagnostico Integral, Ocampo, Mexico; Francisco Patron – Hospital Dalinde, Mexico, Mexico; Gilberto Paz – Centro de Especialidades Medicas, Guadalajara/Jalisco, Mexico; Gabriel Perez – Sanatorio Moderno, Guanajuato, Mexico; Enrique Quintero – Michoacan, Mexico; Luis CA Rocha – Hospital das Clínicas da UFPR, Curitiba, Brazil; Arturo Rodriguez – Jalisco, Mexico; Eusebio Rubio-Aurioles – Asociacion Mexicana Para La Salud Sexual, Mexico; Luis Otávio Torres – Belo Horizonte, Brazil; Oscar Varela – Centro Medico Puerta de Hierro, Jalisco, Mexico; Roberto Zamora – Centro Medico Puerta de Hierro, Jalisco, Mexico; Sebastian Zepeda – Coahuila, Mexico.

The authors also thank the clinical operations staff for their excellent trial implementation and support: Scott J. Burke MS (PharmaNet/i3), for his technical and scientific expertise in preparing and completing this manuscript; Maria Josefa Garcia de Polavieja BS (Lilly-España) for her statistical support; Sirel Gurbuz MD (Lilly) for her medical expertise in reviewing this manuscript; Vinay Pagadala BDS PGDACR PGDBM (PharmaNet/i3), for his assistance in the preparation of tables and graphics in this manuscript; and Katherine Robbins BA (PharmaNet/i3), for her editorial assistance.

Some of the data contained in this manuscript were presented at the 14th Congress of the European Society for Sexual Medicine (ESSM) in Milan, Italy in December 2011.