Rehman et al. Health and Quality of Life (2020) 18:138RESEARCHOpen AccessValidation and clinical interpretation of theSt George’s respiratory questionnaire forCOPD (SGRQ-C) after adaptation toMalaysian language and culture, in patientswith COPDAnees ur Rehman1,2* , Mohamed Azmi Ahmad Hassali1, Sabariah Noor Harun1, Sameen Abbas3,Jaya Muneswarao1, Irfhan Ali Bin Hyder Ali4 and Rabia Hussain1AbstractBackground: Cultural differences affect the administration and results of health status questionnaires. “Crosscultural adaptation” ensures retention of psychometric properties such as validity and reliability at an item and/orscale level.Objective: To develop a Malaysian version of St George’s respiratory COPD specific questionnaire (SGRQ-CM), toevaluate the full spectrum of psychometric properties (reliability, validity and responsiveness), to test the factorstructure and to assess minimum clinically important difference for the SGRQ-CM, to be used in population ofMalaysia.Methodology: SGRQ-C was translated to Bahasa Malaysia using a standard protocol. 240 COPD patients wereincluded in the study. All patients were followed-up for six months. Construct validity, internal consistency, itemconvergent validity, test-retest ability, responsiveness, factor analysis and MCID of the Malaysian version of SGRQ-Cto be used in population of Malaysia were evaluated.Results: The Cronbach alpha coefficient and intraclass correlation coefficients (ICC) for SGRQ-CM were reported as0.87, and 0.88 respectively. Correlation of SGRQ-CM with CAT, EQ-5D-5 L, mMRC dyspnea scales and FEV1%predictedwere reported as 0.86, 0.82, 0.72 and 0.42 respectively. Correlation coefficient between the subscales and otherclinical and health status measures ranged from r 0.35 to r 0.87. The MCID was reported as 5.07 ( 2.54–12.67).Conclusion: The Malaysian version of SGRQ-C has a good psychometric property comparable to those of the originalversion and has a strong evidence of validity, reliability and responsiveness towards disease severity in Malaysian COPDpatients. It can be recommended as a reliable quality of life measure for future research.Keywords: SGRQ-C, COPD, MCID, Psychometric validation, Quality of life* Correspondence: [email protected] of Clinical Pharmacy, School of Pharmaceutical Sciences,University Sains Malaysia, Minden, 11800 Penang, Malaysia2Faculty of Pharmacy, Bahauddin Zakariya University, Multan, PakistanFull list of author information is available at the end of the article The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License,which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you giveappropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate ifchanges were made. The images or other third party material in this article are included in the article's Creative Commonslicence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commonslicence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtainpermission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.The Creative Commons Public Domain Dedication waiver ) applies to thedata made available in this article, unless otherwise stated in a credit line to the data.
Rehman et al. Health and Quality of Life Outcomes(2020) 18:138Key Points1. SGRQ-CM has a strong evidence of validity(construct and concurrent), reliability andresponsiveness to disease severity in MalaysianCOPD patients.2. It can be used as a reliable QoL measure in futureresearch, including randomized clinical trials,rehabilitation studies, and QoL studies in COPDpatients.3. It can be used in clinical practice to measuretreatment efficacy for selection of optimal treatment.IntroductionIn addition to spirometric values, Global Initiative forChronic Obstructive Lung Disease (GOLD) 2019 updates recommend to assess impact of chronic obstructive lung disease (COPD) on the health status of patients,disease progression rate and exacerbation frequencyprior to initiation of new therapy . COPD is a multifactorial health problem, having substantial impact onpatients’ financial status and quality of life (QoL) [2, 3].COPD patients experience numerous pulmonary andextra pulmonary symptoms, including dyspnea, cough,sputum, fatigue, insomnia and systemic inflammation.These symptoms are responsible for impaired QoL andcan be assessed through communication with the patientrather than spirometry. Disease activity markers (lungfunction’s parameters, sputum frequency, sputum volume and exacerbation), may not necessarily reflect theoverall impact of the disease on an individual patient .Incorporating health status questionnaires into the clinical investigations of COPD may aid in determining thetreatment efficacy, disease severity and health status ofCOPD patients .In general, QoL questionnaires are widely used to observe patient improvement, responsiveness to ongoingtherapy, verify the lab test values, and effect of clinicalinterventions. They are also helpful in the selection ofmost appropriate therapy among a broad spectrum oftherapeutic interventions. The SGRQ-C is a selfadministered COPD specific questionnaire to evaluatethe comparative measurement of health status based onseverity of disease and can also evaluate the effectivenessof therapy after treatment . It has adequate sensitivityand reliability. Once efficiently translated and validated,it provides a standard metric across cultures and populations [6–9]. It can evaluate disease symptoms, patient’sdaily activity, the impact of COPD on patient’s life andtotal QoL score. Each item in the SGRQ-C questionnairehas a specific weight, which is combined to calculatesubscale or total score . The minimum clinically important difference (MCID) for the SGRQ-C is its response to therapeutic interventions and is used toPage 2 of 12evaluate clinical efficacy of the therapy in COPD patients. MCID is valid and correlates with clinical parameters of respiratory function e.g. forced expiratoryvolume in one second (FEV1) .Cultural differences affect the administration and results of health status questionnaires . Food and DrugAdministration Authority (FDA) requires validation ofpatient reported health status measures in terms of linguistic and cultural adaptation to ensure content validityat the conceptual level among different populations before applying to a new or different population .“Cross cultural adaptation” resolves translation and cultural adaptation issues in using a questionnaire in different ethnicity than the source of origin, and finds contentsimilarity between source and target population . Itensures retention of psychometric properties such as validity and reliability at an item and/or a scale level. Moreover, the translation of the questionnaire to nativelanguage not only improves communication between patient and healthcare professionals, but also helps inmeasuring the exact experience of individuals on QoLdue to influence of the disease without any interferencefrom the health professional .Currently modified medical research council dyspneascale (mMRC scale), COPD assessment test (CAT) andfew generic health status questionnaires e.g. EuropeanQuality of life 5-Dimension 5-Level questionnaire (EQ5D-5 L) are being used in clinical practice in Malaysia.CAT is a short form of SGRQ-C and can only measurerespiratory disability and few activities among patientswith COPD . Whereas, generic questionnaires areless responsive to changes in disease status and are lesseffective for use in clinical trials as they do not focus onaspect, specific to a certain disease [16, 17]. There is aneed for a scale which can measure in detail the fourmain domains of health status that include physiologicalfunctioning, symptoms, functional impairment, andQoL. Translation and validation of SGRQ-C to Malaysian language and culture can cover this gap, as it canassess the detailed symptomatic effect of disease and impaired QoL among COPD patients in clinical practiceand research studies. Bahasa Malaysia is an official language of Malaysia and is spoken by approximately 85%of the Malaysian population . The objective of ourstudy was to develop a Malaysian version of SGRQ-C(SGRQ-CM), to evaluate the full spectrum of psychometric properties (reliability, validity and responsiveness)of the SGRQ-CM, to test the factor structure of SGRQCM and to assess MCID for the SGRQ-CM, to be usedin population of Malaysia.MethodologyThis study was part of a prospective cohort that included patients from the main public hospital of Penang,
Rehman et al. Health and Quality of Life Outcomes(2020) 18:138Malaysia. The study protocol was approved by the National Medical Research Register Malaysia and clinicalresearch center of concerned hospital (Registration number: NMRR-18-1482-42,075). Sample size for validationof the SGRQ-C questionnaire was calculated as 240 (5participants against each item in the instrument with20% drop out rate) . Written informed consent wasobtained from all participants.TranslationThe translated version of the SGRQ-C questionnairewas available from the St George’s library. To verify thetranslated version, a native Malay speaker with goodcommand on English was selected and performed forward translation of SGRQ-C English version to Malaysian language.A team comprising medical experts, academicians andthe translator reviewed the both translated versions ofSGRQ-C and developed a new translated version by resolving conflicts through discussion. To check the validity of the newly Malaysian translated version that itreflects the same content as original version, two independent translators translated the newly MalaysianPage 3 of 12translated version to the English. Then a committee ofexperts comprising health professionals, academiciansand translators (forward translator and backward translators) reviewed the forward and backward translatedversion to come up with a final version of Malaysiantranslated SGRQ-C.The translated version was reviewed critically to validate semantic, idiomatic, experiential and conceptualequivalence. To assess that the translated version still retains its equivalence to the original version, it was filledinitially by 10 COPD patients and the patients wereinterviewed to probe what he/she thought about themeaning of each questionnaire. No difficulty was reported in understanding or answering the questions.Therefore, the Malaysian version of SGRQ-C (SGRQCM) was adopted as the final version of the questionnaire (Fig. 1).Study designData on clinical and health status of COPD patients wascollected from the patients visiting chest clinic of thePenang Hospital. Patients were followed up for sixmonths. Data were collected for all the included patientsFig. 1 Translation and linguistic validation methodology used for translation of the SGRQ-C. *SGRQ-C, St George Respiratory Questionnaire forCOPD; SGRQ-CM, Malaysian version of SGRQ-C
Rehman et al. Health and Quality of Life Outcomes(2020) 18:138at baseline during recruitment, then a repeated evaluation of 20 % patients at an interval of two weeks andthen follow-up evaluation of all patients at an interval ofsix months.Among 240 patients included in the study forty sevenpatients suffered from exacerbation and admitted to theward during the study period. For admitted patients,data were also collected on the last day of admission dueto exacerbation and at an interval of one month afterdischarge when a significant improvement in health status was expected.The patients were included in the study if they had,(1) confirmed diagnosis of COPD (FEV1/FVC 70), (2)minimum of six-month outpatient record to avoidabrupt changes in QoL due to initiation of therapy, (3)no changes in treatment over the past 4 weeks, (4) noother respiratory disorders, (5) no other diseases thathave a short term effect on QoL, and (6) no disability.Patients were clinically assessed and then administeredthe data collection form consisting of demographic data,clinical data, and health status questionnaires (SGRQCM, CAT, EQ-5D-5 L, and mMRC dyspnea scale). Helpwas provided by non-technical staff to complete thequestionnaire, if someone was unable to complete byhimself due to poor eyesight, unable to read or shakyhands. Nondirective guidance was provided if patientshad queries on how to answer questions.For SGRQ-CM questionnaire the recall period forsymptom and activity subscale was “past year” and“these days” respectively. Spirometry was performed according to American Thoracic society guidelines at eachvisit before administration of the data collection form.Severity of COPD was categorized according to spirometry results, in accordance with GOLD 2018 guidelines. Grade I COPD with FEV1 80% predicted, grade IIwith FEV1 50 to 80% predicted, grade III at FEV1 30 to50% predicted, and grade IV with FEV1 30% predicted.Stable COPD patients were defined as patients havingless than 10% change in spirometric values, and no variation in clinical symptoms after two weeks.Health status measuresThree health status measures, CAT, the Malaysian version of EQ-5D-5 L, and mMRC dyspnea scale were simultaneously applied to the study population along withthe SGRQ-CM. CAT is an FDA approved health statusquestionnaire used for assessment of COPD patients.CAT is easy to understand and consist of 8 items relatedto symptoms and activities. Each item has scores 0 to 5from best to worst with a maximum total score of 40. Itsreliability has been already tested in many Europeancount