J AM ACAD DERMATOL
652 Letters
OCTOBER 2013
Measuring quality of life in epidermolysis bullosa in Mexico: Cross-cultural validation of the Hispanic version of the Quality of Life in Epidermolysis Bullosa questionnaire To the Editor: The Quality of Life in Epidermolysis Bullosa (QOLEB) questionnaire is a valid and reliable epidermolysis bullosa (EB)-specific quality-ofLife (QOL) measurement tool.1 It aims to reflect clinically significant changes in disease status and well-being as opposed to purely physical attributes such as new blister formation, which may improve with interventions but have no clinically significant impact upon function, emotional status, or survival.1,2 Cross-cultural validation of questionnaires enable the use of questionnaires in international multicenter clinical research, allow comparison of burden of disease, and encourage much-needed funding, particularly in regions or population groups where health care is not widely accessible or affordable.3,4 This study aims to develop a valid, culturally appropriate translation of the QOLEB questionnaire for use in Hispanic populations. The validated, guideline-based methodology of this study3,4 comprised 5 separate steps: ethical approval, forward and backward translation, expert committee review, pretesting, and statistical analysis. The final Hispanic translation of the QOLEB questionnaire is available directly from the corresponding author. Patient burden was low, the average time being 4.6 minutes to complete the questionnaire. Of patients, 100% completed the QOLEB questionnaire and the accompanying Skindex-29 questionnaire. Four patients only partially completed the ShortForm 36 (SF-36) questionnaire and these incomplete questionnaires were excluded from analysis.
Demographic data and questionnaire responses are presented in Fig 1. Statistical analysis revealed no ceiling effects in this patient cohort, with floor effects seen in questions 10 and 12. Content validity was addressed through forward-back translation and committee consensus of the conceptual equivalence of the questionnaire. Convergent validity against the physical functioning, physical role functioning, and bodily pain subscales of the SF-36 questionnaire (using the RAND scoring methodology [RAND Corporation, Santa Monica, CA]) was adequate (R ¼ 0.673, R ¼ 0.656, and R ¼ 0.353, respectively). The remaining SF-36 subscales (vitality, general health, social functioning, emotional role functioning, and mental health) showed low correlation with the QOLEB questionnaire (R \ 0.3). Convergent and discriminative validity with the Skindex-29 questionnaire was adequate (R ¼ 0.655 and R ¼ 0.544, respectively), comparable with the statistics of the original questionnaire.1 Construct validity and internal consistency was high with a Cronbach alpha of 0.922. Test-retest reliability was also excellent with a correlation coefficient of 0.985. Principal axis factor analysis identified 2 factors accounting for 63.65% of the total variance of the questionnaire. All questions loaded greater than 0.40 on the same subscales as in the original QOLEB questionnaire.1 Item complexity differed slightly between the questionnaires with all variances being less than 0.07 from the complexity cut-off value with the exception of question 13 (relationships with friends) being strongly aligned with emotions in the Hispanic version (being complex in the original questionnaire). Qualitative feedback from patients suggested that the emotive versus the functional associations between social
Fig 1. Statistical results from Hispanic version of Quality of Life in Epidermolysis Bullosa (QOLEB) questionnaire. AV, Average; RDEB-G, recessive dystrophic epidermolysis bullosageneralized severe; RDEB-O, recessive dystrophic epidermolysis bullosa- other; SD, standard deviation.
J AM ACAD DERMATOL VOLUME 69, NUMBER 4
interactions contributed to a degree of this disparity, consistent with the cultural differences between the original Australian and Mexican settings along the individualistic/collectivist social paradigm.5 The Hispanic QOLEB questionnaire is therefore a valid and reliable translation for use in EB. It has great potential for use in the quantification of QOL in individuals with EB in Hispanic-speaking communities and for use as a QOL outcome tool for multinational clinical trials in the future. John W. Frew, MBBS (Hons), MClin Ep,a,b Rodrigo Cepeda Valdes, MD,e Giulio Fortuna, DMD, PhD,c,d Dedee F. Murrell, MA, BMBCh, FAAD, MD, FACD,a,b and Julio Salas Alanis, MDc,e University of New South Wales,a Sydney, Australia; Department of Dermatology, St. George Hospital,b Sydney, Australia; Department of Basic Sciences, University of Monterrey,c Monterrey, Mexico; Department of Oral Medicine, Carolinas Medical Center,d Charlotte, North Carolina; and DebRA Mexico Association,e Guadalupe, Mexico Funding sources: None. Conflicts of interest: None declared. Correspondence to: Dedee F. Murrell, MA, BMBCh, FAAD, MD, FACD, Department of Dermatology, St George Hospital, Kogarah, Sydney, New South Wales 2217, Australia E-mail:
[email protected]
REFERENCES 1. Frew JW, Martin LK, Nijsten T, Murrell DF. Quality of life evaluation in epidermolysis bullosa (EB) through the development of the QOLEB questionnaire: an EB-specific quality of life instrument. Br J Dermatol 2009;161:1323-30. 2. Fine JD, Eady RAJ, Bauer EA, Bauer JW, Bruckner-Tuderman L, Heagerty A, et al. The classification of inherited epidermolysis bullosa (EB): report of the third international consensus meeting on diagnosis and classification of EB. J Am Acad Dermatol 2008;58:931-50. 3. Beaton DE, Bombardier C, Guillemin F, Ferraz MB. Guidelines for the process of cross-cultural adaptation of self-report measures. Spine 2000;25:3186-91. 4. Acquadro C, Conway K, Hareendran A, Aaronson N. Literature review of methods to translate health-related quality of life questionnaires for use in multinational clinical trials. Value Health 2008;11:509-21. 5. Diaz-Loving R, Draguns JG. Culture, meaning, and personality in Mexico and in the United States. In: Lee YT, McCauley CR, Draguns JG, editors. Personality and person perception across cultures. Mahwah (NJ): Lawrence Erlbaum Associates Publishers; 1999. pp. 103-26. http://dx.doi.org/10.1016/j.jaad.2013.04.053
Letters 653
Pathologic nodal evaluation is increasingly commonly performed for patients with Merkel cell carcinoma To the Editor: Merkel cell carcinoma (MCC) is a virus-associated, neuroendocrine skin tumor with a disease-associated mortality greater than 40%.1 Consistent with this aggressive behavior, clinically localized MCC has nonpalpable microscopic nodal involvement in one third of cases.2 The American Joint Committee on Cancer (AJCC) established a key role for pathologic nodal evaluation in determining the extent of MCC spread for optimal prognostication and disease management.1,3 Historically, rates of pathologic nodal evaluation for MCC have been low. We used national registry data to determine whether rates of pathologic nodal evaluation for patients are increasing. A limitation of national registries is that they have often omitted clinical nodal status information for persons who were subsequently found to be pathologically node-positive (thus making it impossible to determine if pathologically node-positive patients were clinically node-negative at presentation). Therefore, we focused our study on patients who were ultimately classified as having only local disease and examined how often they were proven to be node-negative pathologically as compared to having no clinical evidence of nodal disease (but no pathologic node evaluation). Because multiple studies have demonstrated that cohorts of patients with clinically node-negative MCC have a consistent ratio between occult positive (;33%) and truly pathologically node-negative (;67%) cases, as more patients with clinical node-negative status are pathologically examined, there would be an increase in both microscopically node-positive and node-negative patients.
Fig 1. Pathologic nodal evaluation among patients with local-stage Merkel cell carcinoma (MCC ) 1989 to 2008. N ¼ 2303.
