Combination of qualitative and quantitative methods for developing a new Health Related Quality of Life measure for patients with anogenital warts

Xavier Badia, Colombo Jose, Lara Nuria, Llorens, Olmos Luis, De, Varela Jose, Vilata, Vilata Juan

Description

Anogenital warts are the most easily recognized sign of genital Human Papilloma Virus infection. The objective was to develop a short, valid and reliable questionnaire to measure Health Related Quality of Life (HRQL) in patients with anogenital warts. Methods First a literature review was performed to identify relevant papers describing the impact of anogenital warts in HRQL; second the main domains were identified by some experts in a focus group, and third in-depth-semi-structured interviews were conducted in patients with anogenital warts to identify the initial set of items. A qualitative reduction of the initial set of items was performed based on the mean scoring of the experts for the three scales: clarity, frequency and importance. The initial questionnaire was pilot tested in 135 patients. Rasch analysis was performed with the results of the questionnaire in order to refine the instrument. Spearman's correlation was calculated between the initial questionnaire and the reduced version. Additionally the measurement properties (validity and reliability) of the resulting final questionnaire were tested and compared using standard procedures (Cronbach's Alpha and item-total correlation). Results the main domains identified as affected in patient's life were: sexual, colleagues and partner relationships. After a proper qualitative reduction the initial set of 134 items was reduced to 22. The questionnaire was pilot tested in 135 patients and two dimensions were identified after the multifactorial analysis: emotional dimension and sexual activity dimension. As a result of the Rasch analysis the questionnaire was reduced to 10 items. High correlation was found between the initial and the reduced version for the two dimensions. Cronbach's alpha values were acceptable (0.86). Conclusion The initial 22 items questionnaire was reduced by Rasch analysis to a version of 10 items, with two dimensions: emotional and sexual. The results suggest the adequacy of the 10 items to evaluate HRQL of patients with anogenital warts in a valid and reliable way.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2005
• Nombre de lectures: 7
• Langue: English

Extrait

Health and Quality of Life Outcomes

BioMedCentral

Open Access Research Combination of qualitative and quantitative methods for developing a new Health Related Quality of Life measure for patients with anogenital warts 1 2 1 3 Xavier Badia* , Jose Antonio Colombo , Nuria Lara , M Angels Llorens , 4 3 5 Luis Olmos , Miguel Sainz de los Terreros , Jose Antonio Varela and 6 Juan Jose Vilata

1 2 Address: Health Outcomes Research Europe Group, Avda. Diagonal, 618 1° CD, 08021Barcelona, Spain, Hospital Universitario Puerta del Mar, 3 4 5 Cádiz, Spain, Departamento Médico, 3M España, División Farmacéutica, Madrid, Spain, Hospital Clínico, Madrid, Spain, Unidad ITS, Gijón, 6 Spain and Hospital General Universitario, Valencia, Spain Email: Xavier Badia*  xbadia@horeurope.com; Jose Antonio Colombo  [e-mail]; Nuria Lara  nlara@horeurope.com; M Angels Llorens  [e-mail]; Luis Olmos  [e-mail]; Miguel Sainz de los Terreros  [e-mail]; Jose Antonio Varela  [e-mail]; Juan Jose Vilata  [e-mail] * Corresponding author

Published: 07 April 2005 Received: 26 January 2005 Accepted: 07 April 2005 Health and Quality of Life Outcomes2005,3:24 doi:10.1186/1477-7525-3-24 This article is available from: http://www.hqlo.com/content/3/1/24 © 2005 Badia et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract Background:Anogenital warts are the most easily recognized sign of genital Human Papilloma Virus infection. The objective was to develop a short, valid and reliable questionnaire to measure Health Related Quality of Life (HRQL) in patients with anogenital warts. Methods:First a literature review was performed to identify relevant papers describing the impact of anogenital warts in HRQL; second the main domains were identified by some experts in a focus group, and third in-depth-semi-structured interviews were conducted in patients with anogenital warts to identify the initial set of items. A qualitative reduction of the initial set of items was performed based on the mean scoring of the experts for the three scales: clarity, frequency and importance. The initial questionnaire was pilot tested in 135 patients. Rasch analysis was performed with the results of the questionnaire in order to refine the instrument. Spearman's correlation was calculated between the initial questionnaire and the reduced version. Additionally the measurement properties (validity and reliability) of the resulting final questionnaire were tested and compared using standard procedures (Cronbach's Alpha and item-total correlation). Results:the main domains identified as affected in patient's life were: sexual, colleagues and partner relationships. After a proper qualitative reduction the initial set of 134 items was reduced to 22. The questionnaire was pilot tested in 135 patients and two dimensions were identified after the multifactorial analysis: emotional dimension and sexual activity dimension. As a result of the Rasch analysis the questionnaire was reduced to 10 items. High correlation was found between the initial and the reduced version for the two dimensions. Cronbach's alpha values were acceptable (0.86).

Conclusion:The initial 22 items questionnaire was reduced by Rasch analysis to a version of 10 items, with two dimensions: emotional and sexual. The results suggest the adequacy of the 10 items to evaluate HRQL of patients with anogenital warts in a valid and reliable way.

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