Objective: The aim of this study was to develop a Portuguese-language version of the Epworth sleepiness scale (ESS) for use in Brazil. Methods: The steps involved in creating the ESS in Brazilian Portuguese (ESS-BR) were as follows: translation; back-translation; comparison (by a committee) between the translation and the back-translation; and testing in bilingual individuals. The ESS-BR was applied to a group of patients who were submitted to overnight polysomnography in order to identify obstructive sleep apnea-hypopnea syndrome (OSAHS), insomnia and primary snoring. A control group was composed of subjects with a history of normal sleep habits, without reported snoring. Results: A total of 114 patients and 21 controls were included. The 8-item scores of the ESS-BR had an overall reliability coefficient of 0.83. The study group was composed of 59 patients with OSAHS, 34 patients with primary snoring and 21 patients with insomnia. One-way ANOVA demonstrated significant differences in ESS-BR scores among the four diagnostic groups (p < 0.001). Post-hoc tests between groups showed that the ESS-BR scores of the patients with insomnia did not differ from those of the controls (p > 0.05). The ESS-BR scores were significantly higher for OSAHS patients and for primary snorers than for controls (p < 0.05). In addition, the scores for OSAHS patients were significantly higher than were those for primary snorers (p < 0.05). Conclusions: The results of the present study demonstrate that the ESS-BR is a valid and reliable instrument for the assessment of daytime sleepiness, equivalent to its original version when applied to individuals who speak Brazilian Portuguese.

Keywords: Validation studies; Sleep disorders; Cross-cultural comparison; Disorders of excessive somnolence.

Objective: To develop and validate a Portuguese-language version of the Asthma Control Test (ACT) for use in Brazil. Methods: The study comprised 290 asthma outpatients over 12 years of age. The patients completed the ACT questionnaire and had an appointment with a pulmonologist in order to assess asthma control in two visits. In the first visit, the patients also underwent spirometry. The second visit took place at least four weeks later. Results: We found that a cut-off score of 18 points-to differentiate between subjects with controlled asthma and those with uncontrolled asthma-had a sensitivity of 93%, a specificity of 74%, a negative predictive value of 86% and a positive predictive value of 85%. The positive and negative likelihood ratios were 3.58 and 0.09, respectively. The questionnaire has an outstanding capacity to differentiate uncontrolled asthma from controlled asthma, with an area under the ROC curve of 0.904. The patients whose symptoms remained stable between the two visits had similar scores, demonstrating good test-retest reproducibility, with an intraclass correlation coefficient of 0.93. The patients whose symptoms improved in the second visit had significantly higher scores, demonstrating good responsiveness of the questionnaire in the identification of changes in disease control. Conclusions: The Portuguese-language version of the ACT showed good test-retest reproducibility and was capable of discriminating the levels of asthma control and detecting changes in asthma control in a population of patients with a low level of education and low family income at a public health facility in Brazil.

Keywords: Asthma; Questionnaires; Validation studies; Signs and symptoms.

Objective: To validate a Portuguese-language version of the COPD assessment test (CAT) for use in Brazil and to assess the reproducibility of this version. Methods: This was multicenter study involving patients with stable COPD at two teaching hospitals in the city of Fortaleza, Brazil. Two independent observers (twice in one day) administered the Portuguese-language version of the CAT to 50 patients with COPD. One of those observers again administered the scale to the same patients one week later. At baseline, the patients were submitted to pulmonary function testing and the six-minute walk test (6MWT), as well as completing the previously validated Portuguese-language versions of the Saint George's Respiratory Questionnaire (SGRQ), modified Medical Research Council (MMRC) dyspnea scale, and hospital anxiety and depression scale (HADS). Results: Inter-rater and intra-rater reliability was excellent (intraclass correlation coefficient [ICC] = 0.96; 95% CI: 0.93-0.97; p < 0.001; and ICC = 0.98; 95% CI: 0.96-0.98; p < 0.001, respectively). Bland & Altman plots showed good test-retest reliability. The CAT total score correlated significantly with spirometry results, 6MWT distance, SGRQ scores, MMRC dyspnea scale scores, and HADS-depression scores. Conclusions: The Portuguese-language version of the CAT is a valid, reproducible, and reliable instrument for evaluating patients with COPD in Brazil.

Keywords: Pulmonary disease, chronic obstructive; Questionnaires; Validation studies; Quality of life; Reproducibility of results.

Objective: To translate the Quebec Sleep Questionnaire (QSQ), a specific instrument for the assessment of quality of life in patients with sleep obstructive apnea, into Portuguese and to create a version that is cross-culturally adapted for use in Brazil. Methods: The Portuguese-language version was developed according to a rigorous methodology, which included the following steps: preparation; translation from English into Portuguese in three versions; reconciliation to a single version; back-translation of that version into English; comparison and harmonization of the back-translation with the original version; review of the Portuguese-language version; cognitive debriefing; text review; and arrival at the final version. Results: The Portuguese-language version of the QSQ for use in Brazil had a clarity score, as measured by cognitive debriefing, ranging from 0.81 to 0.99, demonstrating the consistency of translation and cross-cultural adaptation processes. Conclusions: The process of translating the QSQ into Portuguese and creating a version that is cross-culturally adapted for use in Brazil produced a valid instrument to assess the quality of life in patients with obstructive sleep apnea.

Keywords: Obstructive sleep apnea, Quality of life; Translations; Validation studies.

Objective: To translate the London Chest Activity of Daily Living (LCADL) scale into Portuguese and to determine whether this version is reproducible in Brazilian patients with severe chronic obstructive pulmonary disease (COPD). Methods: The LCADL scale was translated into Portuguese and then back-translated into English. This pilot Brazilian Portuguese version was administered to 8 patients with COPD, and possible text-related problems were investigated. The principal problems were discussed with the authors of the original scale, and a final translated version was arrived at. At the study outset, two observers administered this final version (twice in one day) to 31 patients with COPD. One of those observers again administered the scale to the same patients 15-20 days later. At baseline, the patients were submitted to pulmonary function testing and to the six-minute walk test (6MWT). Results: The Brazilian Portuguese version of the LCADL scale demonstrated excellent reproducibility in the total score and in most of the questions, with an inter-rater Cronbach's alpha coefficient of 0.97 (95% CI: 0.89-0.97; p < 0.01) and an intra-rater Cronbach's alpha coefficient of 0.96 (95% CI: 0.83-0.96; p < 0.01). The total score presented a negative correlation with forced expiratory volume in one second in liters (r = −0.49; p < 0.05) and with distance covered on the 6MWT (r = −0.56; p < 0.05). Conclusion: The Brazilian Portuguese version of the LCADL scale is a reliable, reproducible, and valid instrument for evaluating dyspnea during activities of daily living in patients with severe COPD.

Keywords: Activities of daily living; Dyspnea; Diagnostic techniques and procedures; Reproducibility of results.

Objective: To evaluate the properties of the Identity-Consequence Fatigue Scale (ICFS) in patients with lung cancer (LC), assessing the intensity of fatigue and associated factors. Methods: This was a cross-sectional study involving LC patients, treated at a teaching hospital in Brazil, who completed the ICFS. Patients with chronic heart disease (CHD) and healthy controls, matched for age and gender, also completed the scale. Initially, a Brazilian Portuguese-language version of the ICFS was administered to 50 LC patients by two independent interviewers; to test for reproducibility, it was readministered to those same patients. At baseline, the LC patients were submitted to spirometry and the six-minute walk test, as well as completing the Epworth Sleepiness Scale (ESS), Hospital Anxiety and Depression Scale (HADS), Medical Outcomes Study 36-item Short-Form Health Survey (SF-36), and Fatigue Severity Scale (FSS). Inflammatory status was assessed by blood C-reactive protein (CRP) levels. To validate the ICFS, we assessed the correlations of its scores with those variables. Results: The sample comprised 50 patients in each group (LC, CHD, and control). In the LC group, the intraclass correlation coefficients for intra-rater and inter-rater reliability regarding ICFS summary variables ranged from 0.94 to 0.76 and from 0.94 to 0.79, respectively. The ICFS presented excellent internal consistency, and Bland-Altman plots showed good test-retest reliability. The ICFS correlated significantly with FSS, HADS, and SF-36 scores, as well as with CRP levels. Mean ICFS scores in the LC group differed significantly from those in the CHD and control groups. Conclusions: The ICFS is a valid, reliable instrument for evaluating LC patients, in whom depression, quality of life, and CRP levels seem to be significantly associated with fatigue.

Keywords: Fatigue; Lung neoplasms; Symptom assessment.

Abstract Objective: To determine the validity and reproducibility of two subjective instruments to assess limitations in activities of daily living (ADLs) in patients with chronic obstructive pulmonary disease (COPD) in Brazil: the Pulmonary Functional Status and Dyspnea ­Questionnaire ‑ ­Modified version (PFSDQ-M) and the Medical Research Council (MRC) scale. Methods: Thirty patients with COPD (age, 67 ± 10 years; males, 17; forced expiratory volume in one second, 42% ± 13% of predicted) completed the Portuguese-language versions of the two instruments on two occasions, one week apart. The PFSDQ-M has three components: influence of dyspnea on ADLs, influence of fatigue on ADLs and change experienced by the patient with ADLs. The MRC scale is simple, with only five items, in which patients report the degree to which dyspnea limits their performance of ADLs. The traditional Saint George's Respiratory Questionnaire (SGRQ), previously validated for use in Brazil, was used as a validation criterion. Results: The test-retest reliability (intraclass correlation coefficient) of the PFSDQ-M was 0.93, 0.92 and 0.90 for the dyspnea, fatigue and change components, respectively, compared with 0.83 for the MRC scale. Bland-Altman plots showed good test-retest concordance for the PFSDQ-M. The components of the PFSDQ-M and the MRC scale correlated significantly with all of the domains and the total score on the SGRQ (0.49 < r < 0.80; p < 0.01 for all). Conclusions: The Portuguese-language versions of the PFSDQ-M and the MRC scale proved reproducible and valid for use in patients with COPD in Brazil.

Keywords: Pulmonary disease, chronic obstructive; Activities of daily living; Validation studies.

Objective: To adapt the PROactive Physical Activity in COPD-clinical visit (C-PPAC) instrument to the cultural setting in Brazil and to determine the criterion validity, test-retest reliability agreement, and internal consistency of this version. Methods: A protocol for cultural adaptation and validation was provided by the authors of the original instrument and, together with another guideline, was applied in a Portuguese-language version developed by a partner research group from Portugal. The adapted Brazilian Portuguese version was then cross-sectionally administered twice within a seven-day interval to 30 individuals with COPD (57% were men; mean age was 69 ± 6 years; and mean FEV1 was 53 ± 18% of predicted) to evaluate internal consistency and test-retest reliability. Participants also completed the International Physical Activity Questionnaire (IPAQ), the modified Medical Research Council scale, the COPD Assessment Test, and Saint George's Respiratory Questionnaire to evaluate criterion validity. Results: The C-PPAC instrument showed good internal consistency and excellent test-retest reliability: "amount" domain = 0.87 (95% CI, 0.73-0.94) and "difficulty" domain = 0.90 (95% CI, 0.76-0.96). Bland & Altman plots, together with high Lin's concordance correlation coefficients, reinforced that agreement. Criterion validity showed moderate-to-strong correlations of the C-PPAC with all of the other instruments evaluated, especially with the IPAQ (rho = -0.63). Conclusions: The Brazilian Portuguese version of the C-PPAC is a reliable and valid instrument for evaluating the experience of Brazilian individuals with COPD with their physical activity in daily life.

Keywords: Pulmonary disease, chronic obstructive; Validation study; Activities of daily living; Psychometrics.

Objective: The objective of this study was to evaluate the applicability of a modified version of the Saint George's Respiratory Questionnaire. The version evaluated elicits "agree" and "do not agree", rather than "yes" and "no", responses. The intention is to facilitate the comprehension of double-negative questions and to promote better recollection of symptoms by patients by shortening their symptom histories from 12 months to 3 months. Methods: A total of 30 clinically stable patients with chronic obstructive pulmonary disease were evaluated. The Saint George's Respiratory Questionnaire and the modified version of the same were administered 15 days apart. Results: All of the patients presented health-related alterations in their quality of life. Comparing mean scores between the two questionnaires, the greatest difference was seen in the Symptoms domain. No significant differences were found in any of the remaining domains or in the total scores. In a subsequent analysis, significant correlations between the two questionnaires were found in all domains: Symptoms (r = 0.71; p < 0.001); Activity (r = 0.75; p < 0.001); Impact (r = 0.73; p < 0.001) and Total (r = 0.86; p < 0.001). Conclusion: The modified version of the Saint George's Respiratory Questionnaire is as effective as the original in gauging quality of life. However, various symptoms recollection time frames should be investigated in order to determine which would be the best time frame to employ in the analysis.

Keywords: Pulmonary disease, chronic obstructive; Quality of life; Reproducibility of results; Cross-cultural comparison; Questionnaires

Objective: To develop and validate an asthma knowledge questionnaire for use in adult asthma patients in Brazil. Methods: A 34-item self-report questionnaire was constructed and administered to adult asthma patients and adult controls. The maximum total score was 34. Results: The questionnaire was shown to be discriminatory, with good reliability and reproducibility. The mean score for asthma patients and controls was, respectively, 21.47 ± 4.11 (range: 9-31) and 17.27 ± 5.11 (range: 7-28; p < 0.001). The Kaiser-Meyer-Olkin measure of sampling adequacy was 0.53, and the Bartlett's test of sphericity demonstrated a satisfactory suitability of the data to factor analysis (p < 0.001). There was no significant difference between the total scores obtained in the first and in the second application of the questionnaire within a two-week interval (p = 0.43). The internal consistency reliability (KR-20 coefficient) was 0.69. Conclusions: This study has validated an asthma knowledge questionnaire for use in Brazil.

Keywords: Asthma; Questionnaires; Validation studies; Reproducibility of results.

Objective: To translate the Modified Reasons for Smoking Scale (MRSS) to Portuguese, to submit it to cross-cultural adaptation for use in Brazil and to evaluate the test-retest reliability of the translated version. Methods: An English-language version of the MRSS was translated to Portuguese by Brazilian doctors who have thorough knowledge of the English language. A consensus version was produced by a multidisciplinary group including two pulmonologists, a psychiatrist and a psychologist. This version was back-translated to English by an American translator. Cross-cultural adaptation of the final version was evaluated in a sample of 20 healthy smokers. Test-retest reliability was evaluated by applying the translated version of the scale in 54 healthy smokers on two distinct occasions, 15 days apart. Results: This translated version of the MRSS was well understood by 95% of the smokers, indicating excellent cross-cultural equivalence. The degree of reliability of the answers in two different occasions was almost perfect for two questions, substantial for ten questions, moderate for eight questions, and low for one question. The intraclass correlation coefficients of the motivational factors obtained on the two different occasions, calculated according to previously published theoretical models, were higher than 0.7 for six of the seven subscales. Conclusions: The Portuguese-language version of the MRSS shows satisfactory cross-cultural equivalence and test-retest reliability. It can be a useful tool in the evaluation and treatment of smokers in Brazil.

Keywords: Smoking cessation; Scales; Translations; Validation studies.

Objective: To cross-culturally adapt the Wisconsin Smoking Withdrawal Scale (WSWS) for use in Brazil and evaluate the reproducibility of the new (Brazilian Portuguese-language) version. Methods: The original English version of the WSWS was translated into Brazilian Portuguese. For cross-cultural adaptation, the Brazilian Portuguese-language version of the WSWS was administered to eight volunteers, all of whom were smokers. After adjustments had been made, the WSWS version was back-translated into English. The Brazilian Portuguese-language version was thereby found to be accurate. The final Brazilian Portuguese-language version of the WSWS was applied to 75 smokers at three distinct times. For the assessment of interobserver reproducibility, it was applied twice within a 30-min interval by two different interviewers. For the assessment of intraobserver reproducibility, it was applied again 15 days later by one of the interviewers. Intraclass correlation coefficients (ICCs) were used in order to test the concordance of the answers. The significance level was set at p < 0.05. Results: Of the 75 volunteers, 43 (57.3%) were female. The overall mean age was 46.3 years. Interobserver and intraobserver reproducibility was determined for each of the WSWS seven domains, the ICCs for which ranged from 0.87 to 0.94 and from 0.76 to 0.92, respectively. The mean time to completion of the WSWS was 6 min and 44 s, and the response time per question ranged from 4.2 to 12.6 s. Conclusions: The Brazilian Portuguese-language version of the WSWS is reproducible, fast, and simple. It can therefore be used as a tool for assessing the severity of the symptoms of nicotine withdrawal syndrome.

Keywords: Nicotine; Tobacco use disorder; Substance withdrawal syndrome; Reproducibility of results.

Objective: To evaluate the performance of the No-Apnea score, a simplified screening instrument for obstructive sleep apnea (OSA), by gender. Methods: This was a cross-sectional study including adults undergoing full polysomnography. The No-Apnea model comprises two items (neck circumference and age) with a total score of 0 to 9. The severity of OSA was categorized, on the basis of the apnea-hypopnea index, as any (≥ 5 events/h), moderate-to-severe (≥ 15 events/h), or severe (≥ 30 events/h). The performance of the No-Apnea instrument was assessed by determining the area under the (ROC) curve (AUC) and by constructing contingency tables. Results: We evaluated a total of 6,606 adults (53.8% men). For categorizing the level of OSA severity, the No-Apnea score had a sensitivity of 83.9-93.0% and a specificity of 57.3-35.2%. At all OSA severity levels, the No-Apnea score exhibited higher sensitivity and lower specificity in men than in women. The No-Apnea score proved to be an appropriate screening model for patients in general or when separated by gender or severity of OSA (AUC > 0.7 for all). The discriminatory power of the No-Apnea score to predict any, moderate-to-severe, and severe OSA was similar between genders (p = 0.109, p = 0.698, and p = 0.094, respectively). Conclusions: In a sample of adults referred to the sleep laboratory, there was no significant difference between men and women in terms of the discriminatory power of the No-Apnea instrument in for screening for OSA severity.

Keywords: Sleep apnea, obstructive/diagnosis; Polysomnography; Sex; Surveys and questionnaires.

Objective: To assess the psychometric properties of the official Brazilian Portuguese-language version of the Paediatric Asthma Quality of Life Questionnaire (PAQLQ) in a representative group of Brazilian children and adolescents with asthma. Methods: A total of 125 individuals with asthma, aged 8-17 years and being monitored at a pediatric pulmonology outpatient clinic in the city of Porto Alegre, Brazil, completed the PAQLQ. Validity was assessed by means of convergent validity (correlation between PAQLQ domains and those of the Pediatric Quality of Life Inventory (PedsQL) 4.0. Reliability was assessed by determining internal consistency (Cronbach's alpha coefficient), reproducibility (intraclass correlation coefficient), sensitivity to change (effect size), and discriminatory power (floor/ceiling effects). Results: The mean age was 11 years, and 75 (60%) of the participants were male. The mean PAQLQ total score was 5.1, with floor/ceiling effects < 10%. Correlations between PAQLQ domains and the PedsQL 4.0 domains were acceptable (r = 0.37-0.40). The Cronbach's alpha coefficient for the total score was 0.93, ranging from 0.72 to 0.88 for the domains. The overall effect size was 0.60 (range: 0.45-0.60), whereas the overall intraclass correlation coefficient was 0.80 (range: 0.66-0.79). Conclusions: The official Brazilian Portuguese-language version of the PAQLQ showed good psychometric performance, confirming its cultural adequacy for use in Brazil.

Keywords: Keywords: Quality of life; Asthma; Validation studies.

To describe the intra-rater and inter-rater reliability of the Brazilian Portuguese version of the fatigue severity scale (FSS) in patients with COPD and to identify the presence of its association with parameters of pulmonary function, dyspnea, and functional capacity. Methods: This was an observational cross-sectional study involving 50 patients with COPD, who completed the FSS in interviews with two researchers in two visits. The FSS scores were correlated with those of the Medical Research Council (MRC) scale, as well as with FEV1, FVC, and six-minute walk distance (6MWD). Results: The mean age of the patients was 69.4 ± 8.23 years, whereas the mean FEV1 was 46.5 ± 20.4% of the predicted value. The scale was reliable, with an intraclass correlation coefficient of 0.90 (95% CI, 0.81-0.94; p < 0.01). The FSS scores showed significant correlations with those of MRC scale (r = 0.70; p < 0.01), as well as with 6MWD (r = −0.77; p < 0.01), FEV1 (r = −0.38; p < 0.01), FVC (r = −0.35; p < 0.01), and stage of the disease in accordance with the Global Initiative for Chronic Obstructive Lung Disease criteria (r = 0.37; p < 0.01). Conclusions: The Brazilian Portuguese version of the FSS proved reliable for use in COPD patients in Brazil and showed significant correlations with sensation of dyspnea, functional capacity, pulmonary function, and stage of the disease.

Keywords: Fatigue; Pulmonary disease, chronic obstructive; Reproducibility of results; Validation studies.

Objective: To investigate the reliability, internal consistency and validity of the Brazilian Portuguese version of the University of California San Diego Shortness of Breath Questionnaire (UCSD SOBQ) in patients with interstitial lung disease (ILD). Methods: Patients with ILD completed the questionnaire at three different time points, one week apart, with the assistance of two independent assessors. Intra- and inter-rater reliability were analysed via the intraclass correlation coefficient (ICC). Internal consistency was assessed with the Cronbach's alpha coefficient. For the validity analysis, associations between variables were assessed with Spearman's or Pearson's correlation coefficient. Results: Thirty patients with ILD (idiopathic pulmonary fibrosis, connective tissue disease-associated pulmonary fibrosis, sarcoidosis, asbestosis or non-specific interstitial pneumonia) were included (15 men; mean age, 59 ± 10 years; DLCO: 46 [33-64] % predicted). UCSD SOBQ scores showed excellent agreement and internal consistency in the intra-rater analysis (ICC: 0.93 [0.85-0.97]; Cronbach alpha: 0.95) and in the inter-rater analysis (ICC: 0.95 [0.89-0.97]; Cronbach alpha: 0.95), as well as correlating significantly with dyspnoea (as assessed by the Medical Research Council scale; r = 0.56); Medical Outcomes Study 36-item Short-Form Health Survey domains bodily pain, general health, vitality and physical functioning (-0.40 = r = -0.74); six-minute walk distance (r = -0.38); and quadriceps muscle strength (r = -0.41). Conclusions: The Brazilian Portuguese version of the UCSD SOBQ is valid, is reliable and has internal consistency in patients with ILD in Brazil.

Keywords: Lung diseases, interstitial; Dyspnea; Surveys and questionnaires.

Objective: To validate the Portuguese-language version of the STOP-Bang (acronym for Snoring, Tiredness, Observed apnea, high blood Pressure, Body mass index, Age, Neck circumference, and Gender) questionnaire, culturally adapted for use in Brazil, as a means of screening for obstructive sleep apnea (OSA) in adults. Methods: In this validation study, we enrolled patients ≥ 18 years of age, recruited between May of 2015 and August of 2016. All patients completed the STOP-Bang questionnaire and underwent overnight polysomnography. To evaluate the performance of the questionnaire, we used contingency tables and areas under the (receiver operating characteristic) curve (AUCs). Results: We included 456 patients. The mean age was 43.7 ± 12.5 years, and 291 (63.8%) of the patients were male. On the basis of the apnea-hypopnea index (AHI), we categorized OSA as mild/moderate/severe (any OSA; AHI ≥ 5 events/h), moderate/severe (AHI ≥ 15 events/h), or severe (AHI ≥ 30 events/h). The overall prevalence of OSA was 78.3%, compared with 52.0%, and 28.5% for moderate/severe and severe OSA, respectively. The most common score on the STOP-Bang questionnaire was 4 points (n = 106), followed by 3 points (n = 85) and 5 points (n = 82). An increase in the score was paralleled by a reduction in sensitivity with a corresponding increase in specificity for all AHI cut-off points. The AUCs obtained for the identification of any, moderate/severe, and severe OSA were: 0.743, 0.731, and 0.779, respectively. For any OSA, the score on the questionnaire (cut-off, ≥ 3 points) presented sensitivity, specificity, and accuracy of 83.5%, 45.5%, and 75.2%, respectively. Conclusions: The STOP-Bang questionnaire performed adequately for OSA screening, indicating that it could be used as an effective screening tool for the disorder.

Keywords: Sleep apnea, obstructive/diagnosis; Polysomnography; Diagnostic techniques and procedures; Surveys and questionnaires.

Objective: To evaluate the construct validity and reproducibility of the six-minute step test (6MST) in individuals with obstructive sleep apnea (OSA) treated with continuous positive airway pressure (CPAP). Methods: We evaluated 48 volunteers diagnosed with OSA and treated with CPAP for at least two months. The volunteers underwent the six-minute walk test (6MWT) and the 6MST, in random order and on different days, with an interval of, at most, seven days between the two tests. Results: A moderate positive correlation was found between the distance walked on the 6MWT and the number of steps climbed on the 6MST (r = 0.520; p < 0.001). There was no significant difference between the two 6MSTs in terms of the number of steps climbed (121.7 ± 27.1 vs. 123.6 ± 26.7). Reproducibility for performance on the 6MST and for cardiovascular variables was considered excellent (intraclass correlation coefficient > 0.8). Regarding cardiovascular responses, the 6MST produced higher values than did the 6MWT for HR at six minutes, percent predicted maximum HR, and leg fatigue at six minutes, as well as for systolic blood pressure at six minutes and at one minute of recovery. Conclusions: The 6MST is valid and reproducible, producing greater cardiovascular stress than does the 6MWT. However, the 6MST is also characterized as a submaximal test for the assessment of exercise tolerance in individuals with OSA treated with CPAP.

Keywords: Sleep apnea, obstructive; Reproducibility of results; Exercise test; Exercise tolerance.

Introduction: The term quality of life has gained increasing importance in the scientific context. This study describes the adaptation of a disease-specific questionnaire developed by Paul Jones et al. in 1991, the St. George's Respiratory Questionnaire (SGRQ), to the Brazilian language and culture. This questionnaire evaluates the quality of life in patients with chronic obstructive pulmonary disease (COPD) and contains three domains (symptoms, activity, and impacts) divided in 76 items. The questionnaire is self-administrated, but it may be read to illiterate persons. Goal: To verify if the St. George's Respiratory Questionnaire is a valid tool to measure quality of life in patients with chronic obstructive pulmonary disease in Brazil. Methods: In order to validate the questionnaire in Brazil, it was initially translated into Portuguese and afterwards a back-translation into English, that was compared to the original version. A final Portuguese version was then written. This final version was, then, answered by 30 clinically stable COPD patients, according to the spirometry and oximetry values. Patients answered the questionnaire twice, within a 15 day interval. The length of time the patients took to answer the questionnaire and their doubts were noted. Wilcoxon test was used for the calculation of r probability between every single question between the two days; interclass correlation ratio was calculated to test the trustworthiness and reliability of the questionnaire. Results: Among the 30 participant patients, 10 were female and 20 were male. Mean age was 65.9 years. Most of the patients were found to be in stage 2 (56.7 %) of COPD, according to the American Thoracic Society classification. The interclass correlation ratio for the total score of the questionnaire was a = 0.79 and Wilcoxon p = 0.2110 (not statistically significant). The mean answering time for the two days of interview was, respectively, 11 minutes and 50 seconds and 10 minutes and 31 seconds. As concerns the doubts about the questions, the patients reported difficulties in answering Sections 4 and 5, each one of these questions written in a negative form. Conclusion: It can be concluded that the Brazilian version of the St. George's Respiratory Questionnaire is a valid and reliable tool to measure quality of life in patients with COPD in Brazil.

Keywords: obstructive lung diseases, questionnaire, quality of life, reproducibility of results, evolution studies