Actas Dermosifiliogr. 2019;110(7):554---560 ORIGINAL ARTICLE Development and Preliminary Validation of the HSQoL-24 Tool to Assess Quality of Life in Patients With Hidradenitis Suppurativa夽 S.E. Marrón,a,h,i,∗ M. Gómez-Barrera,b,c L. Tomás-Aragonés,g,h,i R.M. Díaz Díaz,d,i E. Vilarrasa Rull,e M.B. Madrid Álvarez,f,i L. Puige a Servicio de Dermatología, Hospital Royo Villanova, Zaragoza, España b Universidad San Jorge, Villanueva de Gallego, Zaragoza, España c Pharmacoeconomics & Outcomes Research Iberia, Pozuelo de Alarcón, Madrid, España d Servicio de Dermatología, Hospital Infanta Sofía, San Sebastián de los Reyes, Madrid, España e Servicio de Dermatología, Hospital de la Santa Creu i Sant Pau, Barcelona, España f Servicio de Dermatología, Hospital Dr. Negrín, Las Palmas de Gran Canaria, España g Departamento de Psicología, Universidad de Zaragoza, Zaragoza, España h Grupo Aragonés de Investigación en Psicodermatología (GAI+PD), Zaragoza, España i Grupo Español de Investigación en Dermatología y Psiquiatría (GEDEPSI) de la Academia Española de Dermatología y Venereología (AEDV), Madrid, España Received 11 November 2018; accepted 7 February 2019 Available online 28 July 2019 KEYWORDS Abstract Hidradenitis Introduction and objectives: Hidradenitis suppurativa (HS) is a chronic inflammatory disease suppurativa; of the skin with a negative impact on quality of life. Up to now, there are no disease specific Quality of life; instruments in Spanish to assess quality of life in HS. The objective of this study was to develop Patient-informed and validate a questionnaire to evaluate the quality of life in patients with HS. results; Material and methods: A multicentre study was carried out in Spain between 2016 and 2017 to Questionnaire design; develop the questionnaire. Both the conceptual framework and understanding of the patient’s Psychometric situation were considered through a review of the literature, consensus of professionals from validation different related health areas, and in-depth interviews with patients. The resulting ques- tionnaire was passed to a group of 30 patients with 30±10 days of interval between both assessments. 夽 Please cite this article as: Marrón SE, Gómez-Barrera M, Tomás-Aragonés L, Díaz Díaz RM, Vilarrasa Rull E, Madrid Álvarez MB, et al. Desarrollo y validación preliminar del instrumento HSQoL-24 para evaluar calidad de vida en pacientes con hidradenitis supurativa. Actas Dermosifiliogr. 2019;110:554---560. ∗ Corresponding author. E-mail address: semarron@aedv.es (S.E. Marrón). 1578-2190/© 2019 Elsevier España, S.L.U. and AEDV. Published by Elsevier España, S.L.U. All rights reserved. Development and Preliminary Validation of the HSQoL-24 Tool 555 Results: The reliability analysis shows a good internal consistency and reproducibility with Cron- bach’s alpha score of 0.920 (test) and 0.917 (retest) and intraclass correlation coefficient with DLQI and Skindex-29 of 0.698 95% CI (0.456-0.844) and 0.900 95% CI (0.801-0.951) respectively. Cut-off points were established for its use and the instrument was found to be sensitive to change. Conclusions: The HSQoL-24 is the first disease-specific self-administered instrument to assess quality of life in patients with HS in Spanish. It is user friendly, and easy to score. This study shows that the instrument is reliable, valid and sensitive to change, pending confirmatory study with a larger sample of 100 patients with HS. © 2019 Elsevier España, S.L.U. and AEDV. Published by Elsevier España, S.L.U. All rights reserved. PALABRAS CLAVE Desarrollo y validación preliminar del instrumento HSQoL-24 para evaluar calidad de Hidradenitis vida en pacientes con hidradenitis supurativa supurativa; Resumen Calidad de vida; Introducción y objetivos: La hidradenitis supurativa (HS) es una enfermedad inflamatoria Resultados crónica de la piel que influencia negativamente la calidad de vida. En la actualidad no existen informados por los escalas en español que la evalúen. El objetivo del presente estudio fue desarrollar y validar un pacientes; cuestionario específico para evaluar la calidad de vida en pacientes con HS. Diseño de Material y métodos: Se desarrolló un estudio multicéntrico en España entre 2016 y 2017 para cuestionario; elaborar un cuestionario. Para ello se consideró tanto el marco conceptual como el conocimiento Validación de la situación del paciente mediante la revisión de la bibliografía, reuniones de profesionales psicométrica de diferentes áreas y entrevistas con pacientes. El cuestionario resultante se pasó a un grupo de 30 pacientes con 30 ± 10 días de intervalo entre uno y otro. Resultados: El análisis de fiabilidad muestra una buena consistencia interna y reproductibilidad con puntuación alfa de Cronbach de 0,920 (test) y 0,917 (retest) y coeficiente de correlación intraclase con DLQI y Skindex-29 de 0,698 IC 95% (0,456-0,844) y 0,900 IC 95% (0,801-0,951) respectivamente. Se establecieron puntos de corte para su uso y se comprobó que el instrumento es sensible al cambio. Conclusiones: El cuestionario HSQoL-24 es la primera prueba autoadministrada específica para evaluar la calidad de vida en HS en español. Sencillo de usar y puntuar por los profesionales. Este estudio demuestra que el instrumento es fiable, válido y sensible al cambio, pendiente de realizar estudio confirmatorio con una muestra mayor con 100 pacientes con HS. © 2019 Elsevier España, S.L.U. y AEDV. Publicado por Elsevier España, S.L.U. Todos los derechos reservados. Introduction quality of life of patients with HS according to current devel- opment standards. Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease with negative physical and psychosocial Material and Methods effects.1,2 HS affects quality of life.3 Matusiak et al.4 analyzed areas The study population comprised 30 adults with HS, all of quality of life that were altered in patients with HS of whom signed the informed consent document. The and found a marked effect on the patient-partner relation- study (PI16/020) was approved by the Clinical Research ship, sexual relations, and family life. Suicidal ideation was Ethics Committee of Aragon (CEICA) on February 10, 2016 recorded in some cases, and loss of work because of the and by the corresponding committees in the other hos- disease was frequent. pitals. Patients were recruited at Hospital Royo Villanova The recent advent of new noninvasive procedures for (Zaragoza), Hospital Infanta Sofía (Madrid), Hospital Santa early diagnosis of the disease5 and novel therapeutic tar- Creu i Sant Pau (Barcelona), and Hospital Doctor Negrín (Las gets will revolutionize our approach to HS.6 Therefore, given Palmas de Gran Canaria). that HS is a very specific disease, this new scenario requires an instrument for measuring the quality of life of affected patients. However, our literature review showed that there Generation of Items was no such instrument in Spanish. The objective of the present study was to develop a new First, we performed a literature review in PubMed in order psychometric questionnaire----the HSQoL-24----to evaluate the to identify relevant psychosocial determinants in HS. These 556 S.E. Marrón et al. were used to identify areas for assessment in the inter- analysis and comparison with the Skindex-29 categories. views. Second, semistructured interviews were held with 12 Sensitivity to change was analyzed based on correlations patients (5 women and 7 men aged 18-61 years) who had between differences in the scores for the 3 questionnaires been diagnosed with HS by a dermatologist. Third, once the and on effect size. interviews had been transcribed and coded, an expert panel HSQoL-24 was developed by a group of experts from was formed by 20 experts with broad clinical experience in the Grupo Aragonés de Investigación en Psicodermatología order to generate new items. A 24-item psychometric instru- (GAI + PD, Aragon Group for Research in Psychodermatology) ment (HSQoL-24) was then drafted. The questions referred and the Grupo Español de Investigación en Dermatología to the 4-week period preceding completion of the question- y Psiquiatría (GEDEPSI, Spanish Group for Research in naire, since the clinical course of HS is relatively stable over Dermatology and Psychiatry) of the Academia Española time compared with other skin conditions. The items were de Dermatología y Venereología (AEDV, Spanish Academy grouped into 6 domains: psychosocial, economic, occupa- of Dermatology and Venereology). An initial development tional, relationships, personal, and clinical. phase was proposed in 30 patients----the object of the present study----with subsequent confirmation in 100 patients. The Psychometric Evaluation resulting questionnaire, HsQoL-24, with 24 items and 5 pos- sible replies for each one (Fig. 1), proved to be feasible and easy to use by patients, who took approximately 10 minutes The psychometric validation of HSQoL-24 was based on the to answer the questions. Dermatology Life Quality Index (DLQI),7 which is a specific questionnaire for evaluating the quality of life of patients with skin conditions, and the Skindex-29 questionnaire, which had been adapted and validated in Spanish by Jones- Caballero et al.8 This is also used to evaluate the quality of Results life of patients with skin diseases. Reliability was evaluated using internal consistency The HSQoL-24 was validated in the sample of 30 patients. analysis with the Cronbach ␣ (acceptable if > 0.7) and repro- The questionnaire was completed on 2 occasions with an ducibility analysis with the intraclass correlation coefficient interval of 30 ± 10 days between them. Eleven of the (ICC) (adequate if > 0.7). Content validity was assessed patients (36.7%) were men, mean (SD) age was 36.8 (11.2) based on the critical opinion of the 20 experts. Construct years, age at onset was 22.8 (10.9) years, and time since validity was assessed using a correlation and regression onset was 13.6 (11.3) years. Six patients (20%) were in Hur- analysis with DLQI and Skindex-29. The cut points were cal- ley stage III, 14 (46.7%) in Hurley stage II, and 10 (33.3%) in culated using receiver operating characteristic (ROC) curve Hurley I. HSQoL-24 Never Rarely Sometimes Often Always 1 My skin condition affects my state of mind. 2 I am concerned about the cost of treatment. 3 My skin condition is worse with stress. 4 My skin condition makes it hard for me to carry out my work. 5 I have resigned myself to living with my skin condition. 6 My skin condition affects my personal relationships. 7 I am concerned about the lack of effectiveness of the treatment. 8 I am concerned about the lack of workplace protection because of my skin condition. 9 My family are my best support with respect to my skin condition. 10 I feel alone or isolated because of my skin disease. 11 Water (bathing, showering) aggravates my skin lesions. 12 Information on my skin condition helps me to accept it. I am concerned about having to giving up certain activities because of 13 my skin condition. 14 My skin condition affects my sleep. 15 My skin condition has led me to think about committing suicide. 16 I have a positive opinion about the initiatives taken by professionals to improve my skin condition. 17 I am concerned that one of my children could have my skin condition. 18 My skin condition is a problem with respect to my intimate relationships 19 Keeping up with treatment and check-ups for my skin condition is sometimes difficult. 20 I am concerned about the bad smell caused by my skin disease. 21 I am concerned about the adverse effects of the treatments for my skin condition. 22 I avoid talking about my skin condition. 23 I am concerned about being rejected because of my skin condition. 24 I feel embarrassed by my skin condition. © Servando E. Marrón 2018 Figure 1 HSQoL-24 questionnaire. The English in the figure is a literal, nonvalidated translation for information purposes only. Development and Preliminary Validation of the HSQoL-24 Tool 557 Table 1 Value of Constants in Each Domaina 0.900 (95% CI, 0.801-0.951), respectively. The results are presented in Table 2. Domain Constant Value Total 1.04166 Validity Analysis Psychosocial 2.08333 Economic 25.0 Correlation and Regression Analysis Occupation 12.5 Relationships 6.25 Construct validity was assessed using a correlation and Personal 12.5 regression analysis with DLQI and Skindex-29. Table 3 shows Clinical 8.33 the values for the correlation between HSQoL-24 and DLQI a The scores for each domain and the overall score are refer- and between HSQoL-24 and Skindex-29, both for the initial enced to 100. evaluation (test) and the subsequent evaluation (retest). The table shows how the correlation values are greater in the comparison with Skindex-29 and that they are close to Properties of HSQoL-24 0.9 (0.863 and 0.898 for test and retest, respectively). A regression analysis was performed for HSQoL-24 with The various items were grouped into 6 domains, as follows: respect to DLQI and Skindex-29 in the initial and subsequent psychosocial, items 1, 3, 5, 7, 10, 12, 15, 17, 20, 22, 23, evaluation. Table 4 shows the results of the initial evaluation and 24; economic, item 2; occupation, items 4 and 8; rela- (test). The R2 values for Skindex-29 revealed an adequate tionships, items 6, 9, 13, and 18; personal, items 11 and goodness of fit for the model (0.7452 and 0.7548 for test 14; and clinical, items 16, 19, and 21. When calculating the and retest, respectively). Therefore, DLQI makes it possible scores, it is necessary to remember that, as a rule, each to predict 47%-50% of the value of variance in HSQoL-24; item is scored from 0 to 4, as follows: 0, never; 1, rarely; Skindex-29 shows a greater fit for the model, accounting for 2, sometimes; 3, often; and 4, always. Items 9, 12, and 16 75%-80% of the variance in HSQoL-24. are scored inversely with respect to the others. Finally, the scores for each domain and the total score must be adjusted Cut Points to 100, which is done by multiplying the value obtained by a constant (Table 1). The cut points were delimited by comparing the range of values for HSQoL-24 and Skindex-29, since the latter yielded the best correlation and regression values. Table 5 shows the Reliability: Internal Consistency and results of the descriptive study of the HSQoL-24 values in the Reproducibility different categories of Skindex-29. We can see that quality of life was not affected in only 8 and 10 patients and that it Internal Consistency was severely affected in 14 and 13 patients. ROC curve analysis showed that values of between 0 and The values for internal consistency (Cronbach ␣) were 0.920 32 in HSQoL-24 correspond to patients whose health-related in the initial evaluation (test) and 0.917 in the subsequent quality of life (HRQoL) is not affected, with a sensitivity of evaluation (retest). 0.909 and a specificity of 0.5. The area under the curve was 0.943 (95% CI, 0.865-1.000). As for patients whose HRQoL was severely affected, the cut point of the proposed curve Reproducibility was 42, with a sensitivity of 0.933 and a specificity of 0.867. The area under the curve was 0.967 (95% CI, 0.909-1.000). Reproducibility was measured using the ICC in a test-retest The separation between the categories mild and moderate intervention. The evaluation was for total score and for the was proposed at a cut point of 36, with a sensitivity of 0.810 scores in the individual domains. The values of the ICC for and specificity of 0.889 and an area under the curve of 0.910 DLQI and Skindex-29 were 0.698 (95% CI, 0.456-0.844) and (95% CI, 0.807-1.000) (Fig. 2). Table 2 Intraclass Correlation Coefficient. Domain ICC (95% CI) Mean (SD), Test Mean (SD), Retest P Value, Test-Retesta Total 0.842 (0.694-0.921) 50.87 (20.695) 47.60 (19.866) .098 Psychosocial 0.872 (0.750-0.937 49.38 (22.346) 45.76 (21.949) .088 Economic 0.709 (0.474-0.850) 40.00 (40.258) 40.00 (40.258) .546 Occupation 0.682 (0.431-0.835) 51.67 (34.072) 46.25 (30.469) .259 Relationships 0.760 (0.555-0.878) 63.33 (25.360) 59.79 (23.309) .260 Personal 0.718 (0.487-0.855) 27.92 (24.715) 29.17 (24.197) .712 Clinical 0.702 (0.462-0.846) 58.61 (19.013) 55.28 (19.264) .227 Abbreviations: ICC, intraclass correlation coefficient. a t test. 558 S.E. Marrón et al. Table 3 Correlation Analysis. Analysis, Test Analysis, Retest Correlation With Correlation With Correlation With Correlation With DLQI (P Value) Skindex-29 (P Value) DLQI (P Value) Skindex-29 (P Value) Total 0.708 (<.001) 0.863 (<.001) 0.691 (<.001) 0.898 (<.001) Abbreviation: DLQI, Dermatology Life Quality Index. Table 4 Regression Models. Comparison Test Model (R2 )a Retest Model (R2 ) HSQoL-24 and DLQI HSQoL = 0.5732×DLQI + 34.372 (0.5018) HSQoL = 0.615×DLQI + 32.604 (0.4745) HSQoL-24 and Skindex-29 HSQoL = 0.6907 × Skindex + 21.057 (0.7452) HSQoL = 0.7548 × Skindex + 18.418 (0.8057) a R2 , coefficient of multiple determination. Table 5 Values of HSQoL-24 in Skindex-29 Categories. Category Test Retest Cases Mean (SD) Range Cases Mean (SD) Range Not at all (0-24) 8 29.82 (6.51) 16-35 10 27.90 (10.35) 13-41 A little (25-31) 1 44.79 45 2 40.00 (14.14) 30-50 A lot (32-43) 6 37.33 (6.12) 31-47 2 39.00 (5.65) 35-43 Very much (≥44) 14 67.63 (20.67) 35-83 13 66.31 (11.09) 45-83 Sensitivity to Change different areas, and interviews with patients. This work- ing methodology is consistent with that of other authors Sensitivity to change was assessed by calculating the varia- and standard practice in the development of quality of life tion in the 3 questionnaires and analyzing the correlations questionnaires.9,10 between them. The results revealed a statistically signif- The relevance of evaluating quality of life in HS has icant correlation between the change in HSQoL-24 and been highlighted in several studies. Patients see their qual- Skindex-29 (Pearson r = 0.504, P = .004) and no statistically ity of life affected beyond their clinical manifestations, and significant correlation for DLQI, although a tendency was this decline should be analyzed,11,12 as should associated observed (Pearson r = 0.355, P = .055). The effect size for factors.13 In addition to relevance, it is also important to the variation in HSQoL-24, calculated as the difference in generate questionnaires that are applicable to specific popu- means divided by the deviation at baseline was 0.33 (50.87- lations, in this case patients with HS in Spain, thus justifying 47.60/20.695), thus indicating a reduced variation in HRQoL. the need for such research in the study of this disease today. Similar conclusions were reached for Skindex-29, with a Currently available questionnaires on HS are not applica- value of 0.17 (43.2-38.6/25.865), thus indicating in both ble to the Spanish population until they are translated and cases a slight variation in HRQoL in this type of patient in validated. Moreover, instruments of this type had not been both questionnaires. published at the time of the design of and subsequent data The values for the 3 questionnaires revealed differences collection in the present study. Consequently, we did not in the total score and the final score. The mean values envisage a translation of these questionnaires but instead are shown in Fig. 3. We can see how these 3 mean values opted to draft a completely new one.9,14,15 decreased. The psychometric characteristics analyzed in the present study were reliability, validity, and prognostic ability, which are equally well accepted in diseases that affect quality of Discussion life in Spain.16 Reliability was measured in terms of internal consistency The present article analyzes the characteristics of the and/or reproducibility/repeatability. Internal consistency HSQoL-24 questionnaire as a predictor of quality of was measured using the Cronbach ␣.17 The results revealed a life in patients with HS. During the drafting process, value of > 0.9, thus indicating excellent internal consistency, both the conceptual framework and awareness of the which was maintained even when some of the questions patient’s situation were taken into account by means of were eliminated. Similar values were reported by McLellan a literature review, meetings between specialists from et al.,16 namely, 0.955 in physical function and 0.900 in the Development and Preliminary Validation of the HSQoL-24 Tool 559 1,0 1,0 1,0 0,8 0,8 0,8 0,6 0,6 0,6 Sensitivity Sensitivity Sensitivity 0,4 0,4 0,4 0,2 0,2 0,2 0,0 0,0 0,0 0,0 0,2 0,4 0,6 0,8 1,0 0,0 0,2 0,4 0,6 0,8 1,0 0,0 0,2 0,4 0,6 0,8 1,0 1 - Specificity 1 - Specificity 1 - Specificity No involvement Severe involvement Moderate involvement Figure 2 Receiver operating characteristic curves. 60 probably because of the small sample size; therefore, in the 50.9 50 47.6 next stage of the evaluation, we will be able to perform 43.2 a more coherent analysis of the sensitivity and specificity 38.6 40 values of HSQoL-24. 30 28.8 In addition to the parallel variations in test and retest 24.3 quality of life scales commented on above, sensitivity to 20 change was analyzed based on the study of correlations 10 between differences in the questionnaire scores and on effect size. The results showed a statistically significant 0 correlation between change in HSQoL-24 with respect to HSQoL-24 DLQI Skindex-29 Skindex-29, although not DLQI, with a low P value (.055). Test Retest Correlation values of around 0.5 were significant and slightly Figure 3 Test-Retest Comparison for the 3 Questionnaires. lower than in other dermatology questionnaires such as DLQI indicates Dermatology Life Quality Index. the Urticaria Activity Score, which, in its validation phase reached 0.6-0.7 with respect to other questionnaires.21 Nevertheless, the results for HSQoL-24 were considered indi- symptom domain in a quality of life questionnaire in HS. cators of good sensitivity to change. Pinnard et al.15 also reported high values (0.936). Reproducibility, or repeatability, was measured using the Conclusions ICC in a test-retest intervention, assuming that values > 0.7 were adequate. This evaluation was performed for the total The results of the analysis of the psychometric properties of score and for the scores in the individual domains. The ICC HSQoL-24, the first specific self-administered test in Span- values exceeded 0.7 in all domains except for occupation ish for evaluation of quality of life in patients with HS, (0.68). These values are similar to those in other ques- revealed adequate reliability and validity values. Therefore, tionnaires or methods used in dermatology, for example, while awaiting the validation results for 100 patients, these the computer-guided calculation of the Psoriasis Area and findings make HSQoL-24 a very clinically valid instrument in Severity Index (PASI), which reached values of 0.86 (95% CI, terms of the results perceived by patients. 0.80-0.90).18 The different ICC values in the DLQI and Skindex-29 over- lapped considerably with the 95% CI of the ICC in HSQoL-24. Conflicts of Interest Therefore, we can deduce that the ICC values of the 3 ques- tionnaires were similar. The authors declare that they have no conflicts of interest. Construct validity was determined using correlation and regression analysis with DLQI and Skindex-29. High corre- lation coefficient values and appropriate fit of regression References models revealed adequate validity, with a greater corre- lation (r > 0.85) and better goodness-of-fit (R2 > 0.7). As 1. Fimmel S, Zouboulis CC. Comorbidities of hidradenitis suppura- reported elsewhere,15,16 HSQoL-24 showed adequate corre- tiva (acne inversa). Dermatoendocrinol. 2010;2:9---16. lations with these questionnaires, thus indicating adequate 2. Kurzen H, Kurokawa I, Jemec GB, Emtestam L, Sellheyer K, validity. Giamarellos-Bourboulis EJ, et al. What causes hidradenitis sup- The cut points had adequate sensitivity (0.88 and 0.90) purativa? Exp Dermatol. 2008;17:455---6. 3. von der Werth JM, Jemec GB. Morbidity in patients with and a high area under the curve (> 0.9) in the ROC curve hidradenitis suppurativa. Br J Dermatol. 2001;144:809---13. analysis, thus indicating adequate predictive capacity for 4. Matusiak L, Bieniek A, Szepietowski JC. Psychophysical detecting individuals with altered HRQoL. These values were aspects of hidradenitis suppurativa. Acta Derm Venereol. similar to those reported by other authors for other HS 2010;90:264---8. and dermatology questionnaires.19,20 Nevertheless, it was 5. Martorell A, García-Martínez FJ, Jiménez-Gallo D, Pascual JC, not possible to calculate specificity values appropriately, Pereyra-Rodriguez J, Salgado L, et al. An update on hidradenitis 560 S.E. Marrón et al. suppurativa (Part I): Epidemiology, clinical aspects, and defini- patients recruited from an outpatient clinic. J Eur Acad Der- tion of disease severity. Actas Dermosifiliogr. 2015;106:703---15. matol Venereol. 2018;32:313---7. 6. Martorell A, García FJ, Jiménez-Gallo D, Pascual JC, Pereyra- 14. McLellan C, Sisic M, Oon HH, Tan J. Preliminary Validation of the Rodríguez J, Salgado L, et al. Update on hidradenitis HS-QoL: A quality-of-life measure for hidradenitis suppurativa. suppurative (Part II): Treatment. Actas Dermosifiliogr. 2015;106: J Cutan Med Surg. 2018;22:142---6. 716---24. 15. Pinard J, Vieugels RA, Joyce C, Merola JF, Patel M. Hidradenitis 7. Finlay AY, Khan GK. Dermatology life quality index (DLQI) a suppurativa burden of disease tool: Pilot testing of a disease- simple practical measure for routine clinical use. Clin Exp Der- specific quality of life questionnaire. J Am Acad dermatol. matol. 1994;19:210---6. 2018;78, 215-7.e2. 8. Jones-Caballero M, Peñas PF, García-Díez A, Chen MM, Badia X. 16. García de Yébenes Prous MJ, Rodríguez Salvanes F, Car- The Spanish version of Skindex-29 An instrument for measuring mona Ortells L. Validación de cuestionarios. Reumatol Clin. quality of life in patients with cutaneous diseases. Med Clin 2009;5:171---7. (Barc). 2002;118:5---9. 17. Crombach L. Coeffcient Alpha and the internal structure of 9. Sisic M, Kirby JS, Boyal S, Plant L, McLellan C, Tan J. Develop- tests. Psychometrika. 1951;16:297---334. ment of a quality-of-life measure for hidradenitis suppurativa. 18. Fink C, Alt C, Uhlmann L, Klose C, Enk A, Haenssle HA. Precision J Cutan Med Surg. 2017;21:152---5. and reproducibility of automated computer-guided psoriasis 10. Jiménez Hernández D, Tornel Abellán M, González Ortiz JJ. area and severity index measurements in comparison to trained Optimización de un cuestionario mediante un método Delphi physicians. Br J Dermatol. 2019;180:390---6. y una prueba piloto. RevIISE. 2015;3:617---38. 19. Lam C, Liu SW, Townsend HB, Femia AN, Qureshi AA, Vleugels 11. Kouris A, Platsidaki E, Christodoulou C, Efstathoiu V, Dessinioti RA. Development and pilot testing of the cutaneous lupus C, Tzanekatou V, et al. Quality of life and psychosocial impli- screening tool. JAMA Dermatol. 2016;152:60---6. cations in patients with hidradenitis suppurativa. Dermatology. 20. Esmann S, Dufour DN, Jemec GB. Questionnaire-based diagnosis 2016;232:687---91. of hidradenitis suppurativa: specificity, sensitivity and positive 12. Pavon Blanco A, Turner MA, Petrof G, Weinman J. To what extent predictive value of specific diagnostic questions. Br J Dermatol. do disease severity and illness perceptions explain depression, 2010;163:102---16. anxiety and quality of life in hidradenitis suppurativa. Br J Der- 21. Hawro T, Ohanyan T, Schoepke N, Metz M, Peveling-Oberhag A, matol. 2019;180:338---45. Staubach P, et al. The urticaria activity score-validity, reliabil- 13. Kjaersgaard Andersen R, Theut Riis P, Jemec GBE. Factors pre- ity, and responsiveness. J Allergy Clin Immunol Pract. 2018;6, dicting the self-evaluated health of hidradenitis suppurativa -90 e 1185.