Cross-cultural adaptation and validation of the Brazilian Portuguese version of the Edinburgh Claudication Questionnaire

Abstracts

OBJETIVO: Traduzir, adaptar culturalmente e validar a versão em português do Questionário de Claudicação de Edimburgo, específico para avaliar a presença de claudicação intermitente. MÉTODOS: A versão em português do Questionário de Claudicação de Edimburgo foi desenvolvida, após autorização da Universidade de Edimburgo, e aplicada em 217 indivíduos residentes no município de São Paulo, com queixas de dor nas pernas, convidados pelos meios de comunicação de massa a participar da I Campanha de Combate à Doença Arterial Obstrutiva Periférica (DAOP). Na primeira etapa, eles responderam ao Questionário de Claudicação de Edimburgo e a um questionário sobre fatores de risco e antecedentes cardiovasculares. Na segunda etapa, realizaram medidas antropométricas e do índice tornozelo-braquial (ITB) de repouso com Doppler vascular e, nos casos duvidosos, teste de esforço vascular em esteira (TEV). A presença de DAOP foi definida por ITB < 0,90 e/ou por TEV positivo e/ou por DAOP documentada. A análise estatística, que incluiu avaliação de desempenho e comparações das proporções e médias, foi realizada utilizando-se o programa SAS versão 8.2. RESULTADOS: A média de idade dos participantes foi de 60 ± 11,5 anos, com predomínio do sexo feminino (53,4%). A análise de desempenho da versão em língua portuguesa mostrou sensibilidade de 85%, especificidade de 93%, valor preditivo positivo de 80%, valor preditivo negativo de 95% e acurácia de 91%. Não houve diferença no desempenho entre idosos (> 65 anos) e não-idosos. CONCLUSÃO: A versão em português do Questionário de Claudicação de Edimburgo manteve níveis adequados de sensibilidade e especificidade, podendo ser recomendado para o rastreamento de DAOP na prática clínica e em estudos epidemiológicos realizados no Brasil.

Claudicação intermitente; questionário; tradução; adaptação transcultural

ORIGINAL ARTICLE

Cross-cultural adaptation and validation of the Brazilian Portuguese version of the Edinburgh Claudication Questionnaire

Marcia Makdisse; Raimundo Nascimento Neto; Antonio Carlos Palandri Chagas; David Brasil; Jairo Lins Borges; Anderson Oliveira; José Gordillo; Gisele Balsalobre; Luciana Crozariol; Miriam Pinho; Rafaela Oliveira; Ana Fátima Salles

Comitê de Doença Arterial Periférica do "Projeto Corações do Brasil", SBC/Funcor, Setor de Cardiogeriatria-Disciplina de Cardiologia, Universidade Federal de São Paulo, Hospital Israelita Albert Einstein – São Paulo, SP, Brazil

^{Mailing address}

SUMMARY

OBJECTIVE: Translation, cultural adaptation and validation of the Brazilian Portuguese version of the Edinburgh Claudication Questionnaire (ECQ) a specific tool to assess intermittent claudication.

METHODS: The Brazilian Portuguese version of the ECQ was developed after authorization by the University of Edinburgh. It was applied to 217 individuals: São Paulo Capital District residents with complaints of leg pain. Individuals under research were invited through mass communication media to participate in the I Campaign to Fight Peripheral Arterial Disease (PAD). In stage 1, participants filled out the ECQ and another questionnaire on risk factors and cardiovascular history. In stage 2, participants had anthropometric measures and ankle-brachial index (ABI) at rest measured by vascular Doppler. In case of doubt, vascular treadmill test was applied (VTT). PAD condition was defined by ABI < 0.90 and/or positive VTT and/or documented PAD. Statistical analysis – which included performance assessment and the comparison between proportions and means – was performed using SAS software, version 8.2.

RESULTS: Mean age of participants was 60±11.5 years, female sex predominated in the sample studied (53.4%). Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 85%, 93%, 80%, 95% and 91%, respectively. No differences in performance were found between elderly (>65 years)and non-elderly subjects.

CONCLUSION: The Brazilian Portuguese version of the Edinburgh claudication questionnaire maintained good sensitivity and specificity and can be recommended for screening of PAD in clinical practice and epidemiological research in Brazil.

Key words: Intermittent claudication; questionaire; translating (process); transcultural adaptation.

Introduction

Peripheral Arterial Disease (PAD) is a result of artery lumen narrowing and stiffening in the lower limbs as part of the process of systemic atherosclerotic disease. Prevalence is high, and is associated to high risk for fatal and non-fatal cardiovascular events (death, myocardial infarction and cerebral vascular accident)^1-2.

Intermittent claudication is a classical symptom in the PAD condition. It occurs as a result of reduced blood flow to skeletal muscle tissue in lower limbs during exercise. Claudication is characterized by pain or discomfort in the calf, thigh, or gluteus region while walking. Symptoms disappear after less than 10 minutes at rest. Prevalence ranges from 0.4 to 14.4% in the general population depending on specific characteristics of the population being assessed (age, gender, region, among other factors) as well as of method used for diagnosis³.

Ankle-Brachial Index (ABI) is the golden standard for PAD screening since it detects both symptomatic and asymptomatic conditions⁴. The use of claudication questionnaires, however, may help screening PAD both for epidemiologic research purposes and in clinical practice. Claudication questionnaires validated in Brazilian Portuguese are not available in this country today. The Bambuí Project – to assess the prevalence of intermittent claudication in residents of Bambuí, in Minas Gerais State – used a Brazilian Portuguese version of the World Health Organization Questionnaire. However, no published data were found on questionnaire validation or on performance in Brazilian Portuguese⁵.

The purpose of the present study was the translation, cultural adaptation and validation of the Brazilian Portuguese version of the Edinburgh Claudication Questionnaire (ECQ).

Methods

Translation of questionnaire - The translation and cultural adaptation of the original version into Brazilian Portuguese were performed based on methodology previously published⁶, following authorization by Professor Gerry Fowkes, from the University of Edinburgh. The translation was done independently by three members in our team and by two English teachers. As a result, five renditions were made available, with slight differences. The versions were then compared and discussed in a meeting where a consensual choice was made for Version 1. That version was then sent to three other independent translators who are fluent in English and who were not familiar with the original version for backtranslation into English. The three new versions were then compared to generate a consensual version in English (Version 2). When compared to the original version, Version 2 showed to be grammatically and semantically equivalent, which allowed Version 1 to be accepted by the group as the final version for the questionnaire in Brazilian Portuguese.

Questionnaire Validation

Population - The Brazilian Portuguese version of the ECQ was applied to 217 individuals: São Paulo Capital District residents with complaints of leg pain. Individuals under research were invited through mass communication media (television, radio, newspapers) to participate in the I Campaign to Fight Peripheral Arterial Disease (PAD). In Campaign phase 1 - carried out on July 20, 2004 – all participants filled out the claudication questionnaire and another questionnaire on risk factors and cardiovascular history. Stage 2 – in October-November, 2004 – anthropometric measures and Ankle-brachial index (ABI) were taken, and vascular treadmill test (VTT) for threshold ABI values. PAD condition was defined by ABI < 0.90 and/or positive VTT and/or documented PAD. All participants signed the Informed Consent Form.

ABI measure and calculation - To calculate ABI, systolic pressures of brachial arteries, dorsalis pedis and posterior tibial arteries were measured bilaterally after 5 minutes at rest in supine position using a handheld vascular Doppler and aneroid pressure equipment. Four cuff sizes were used (small size adult, median size adult, large size adult and thigh), based on right arm circumference at middle position between acromium and olecranium. ABI was calculated for each lower limb using arm highest systolic pressure as denominator, and ankle highest pressure as numerator⁷.

Vascular treadmill test - Vascular treadmill test was performed only for ABI threshold values (0.91 to 0.94). An incremental protocol was used for VTT on the treadmill at 3 km/hour, inclination from 0 to 15%, with 5% increment every 3 minutes. Pressures were measured with vascular Doppler in supine position at rest and after exercise. The test was considered POSITIVE for the diagnosis of PAD whenever ankle systolic pressure decrease measured at minute 1 after exercise was higher than or equal to 20% as compared to baseline, with baseline recovery time over 3 minutes⁸.

Exclusion criteria - Patients with ABI > 1.40 (noncompressible arteries) and those with limitations or contra-indication to vascular treadmill test, if indicated.

Results from the Edinburgh Claudication Questionnaire - Following original guidelines, result was classified as POSITIVE (=presence of claudication) if responses to questions 1 = "yes" AND 2 = "no" AND 3= "yes" AND 5 = "usually disappear in 10 minutes or less" AND 6 = marked "calf" and/or "thigh" and/or "gluteus region" (irrespective of other sites having also been marked) or NEGATIVE for any combination that differed from the one just described.

Question 4 is not used to define presence, but rather severity of claudication; if "No"=Grade 1 (=lower severity) and if "Yes"=Grade 2 (=higher severity).

Patients with POSITIVE questionnaire were also classified as carriers of "Typical or definitive claudication" (if "calf" had been marked for question 6, irrespective of other sites also having been marked) and "Atypical claudication" (in case "calf" had not been marked, but "thigh" and/or "gluteus region" had been marked, irrespective of other site).

Definition for truly positive/negative and false positive/negative - If the claudication questionnaire was NEGATIVE, and ABI was between 0.91 and 1.40 bilaterally, with no history of documented PAD, classification would be "truly negative". If ABI was < 0.90 with/without a previous history of PAD, "false negative".

If questionnaire was POSITIVE and ABI < 0.90 with/without documented PAD, questionnaire was classified as "truly positive". If ABI was between 0.91 and 1.40, with no previous PAD, and vascular treadmill test was negative, questionnaire classification was "false positive".

Statistical analysis - Questionnaire performance was assessed by SAS software, version 8.2 to calculate sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy with Fleiss Quadratic 95% CI. Diagnosis accuracy was calculated by dividing the number of individuals under correct classification on questionnaire (summing up of truly positives and truly negatives) by the total number of individuals under assessment. Proportions were then compared through chi-square test or Fisher Exact Test, whenever applicable, and means were compared by Student’s "t" test.

Results

Overall results - The Brazilian Portuguese Version of the Edinburgh Claudication Questionnaire can be found in Figure 1.

Mean age of the 217 individuals under assessment was 60 ± 11.5 years (30 to 86 years of age). Females were predominant (53.9%). Prevalence of PAD was 24% (n=52); prevalence of intermittent claudication was 25% (n=55).

In the PAD group individuals were older (65.8 ± 10.3 years versus 58.2 ± 11.3 years, p<0.0001). Males were predominant (61.5% versus 41%, p=0.01). No difference was found between the groups in regard to schooling (7.38 ± 4.38 years at school versus 7.57±3.87 years at school, p=0.786) or coexisting atherosclerotic disease. As for traditional risk factors, higher prevalence was reported for diabetes, dyslipidemia, and smoking in the PAD group. Claudication prevalence, typical claudication and the lack of one or more ankle pulses was significantly higher in PAD individuals (Table 1).

Brazilian portuguese version: performance assessment - Table 2 shows diagnostic performance of the Brazilian Portuguese Version of the Edinburgh Claudication Questionnaire. Portuguese version sensitivity was similar to that of original version (85%, CI95%=0.714-0.927 versus 91.3%, CI95%=0.881-0.945, p=0.675) whereas specificity was lower (93%, CI95%=0.881-0.965 versus 99%, CI95%=0.989-1.00, p=0.001). No difference was found in performance between the elderly (> 65 years of age) and non-elderly (<65 years of age) (Table 3).

Discussion

The Edinburg Claudication Questionnaire was originally developed and validated in English by Professors Leng and Fowkes, University of Edinburgh, In Scotland, with the objective of improving the sensitivity of the WHO Claudication Questionnaire published by Rose in 1962⁹. Although Rose Questionnaire had high specificity level (between 90% and 100%), sensitivity reached up to 9%¹⁰ due to the strict claudication criteria used. As the Edinburgh Questionnaire was developed, performance of the nine questions from the Rose Questionnaire were analyzed to verify whether any changes were needed. At process ending, the questionnaire was reduced to six questions. A diagram was added for exact site of pain, thus making self-application easier.

Sensitivity and specificity were 91% and 99% in the version originally published by Leng and Fowkes in 1992, higher than the valves obtained by the Rose Questionnaire¹¹. In 2000, Aboyans and cols. published a French version of the questionnaire with 86.5% sensitivity and 95.6% specificity¹². In 2002, in another publication of the French version validation, Lacroix and cols. found difference in questionnaire performance, especially in regard to sensitivity (sensitivity= 47% and specificity 98.8%)¹³.

The Brazilian Portuguese version of the Edinburg Claudication Questionnaire presented in this study showed 85% sensitivity, 93% specificity, 80% positive predictive value, 95% negative predictive value, and 91% accuracy. When compared to data in literature – showing a 15 at 91% range in sensitivity and a 91.3 to 99% range in specificity when the English version was used for different populations – the performance of Brazilian Portuguese version was ranked as very good¹⁴.

When compared to the original English version, the Brazilian Portuguese version showed lower sensitivity (85% versus 91%, p=0.675) and specificity (93% versus 99%, p=0.001) levels, although the difference in specificity did reach statistical significance. That may have occurred due to differences in population characteristics, and in the methodology used for validation. In the English version, PAD diagnosis was carried out based on clinical assessment only, which increased the chances of matching questionnaire results and the presence of PAD, since both focus symptomatic PAD. The Brazilian version used a methodology similar to the French version¹¹, where the choice was made for a more objective diagnosis method (ABI measure), which detects both symptomatic and asymptomatic patients, and which is closer to clinical practice. Through this methodology, an asymptomatic PAD case would be classified as "false positive", whereas the diagnosis based on clinical history only would be more likely to be classified as "truly negative". On the other hand, a case reporting no PAD with positive claudication on questionnaire could be confirmed by clinical history ("truly positive"), but not by ABI measure ("false positive").

No significant differences could be observed in the performance of the Brazilian Portuguese version among elderly and non-elderly, which allows it to be used for that high risk population for PAD as well.

The good performance of the Brazilian Portuguese version of the Edinburgh Claudication Questionnare presented in this study – where specificity levels were kept above 90% with no loss in sensitivity – makes it recommendable for use in the Brazilian population both for epidemiologic research purposes as in clinical practice.

Acknowledgments

To Libbs Pharmaceuticals for logistic support during the "I SBC-Funcor Campaign to Fight PAD"; to the multidisciplinary team at the Cardiogeriatrics Sector at Unifesp, and to Centro Universitário Nove de Julho – UNINOVE – for having made its facilities available for ABI exams; and to Frederico Moreira, the statistician who performed statistical analyses.

Potential Conflict of Interest

No potential conflict of interest relevant to this article was reported.

References

Manuscript received July 13, 2006; revised manuscript received November 6, 2006; accepted January 17, 2007.

• 1. Newman AB, Shemanski L, Manolio TA, Cushman M, Mittelmark M, Polak JF, for the Cardiovascular Health Study Collaborative Research Group. Ankle-Brachial Index as a Predictor of Cardiovascular Disease and Mortality in the Cardiovascular Health Study. Arterioscler Thromb Vasc Biol. 1999; 19: 538-45.
• 2. Newman AB, Tyrrell KS, Lewis HW. Mortality over four years in SHEP participants with low ankle-brachial index. J Am Geriatr Soc. 1997; 45: 1472-8.
• 3. Criqui MH, Denenber JO, Langer RD, Fronek A. The epidemiology of peripheral arterial disease: importance of identifying the population at risk. Vasc Med. 1997; 2: 221-6.
• 4. Hirsch A, Haskal ZJ, Hertzer NR, Bakal CW, Creager MA, Halperin JL, et al. ACC/AHA Guidelines for the Management of Patients with Peripheral Arterial Disease (Lower Extremity, Renal, Mesenteric, and Abdominal Aortic): A Collaborative Report from the American Association of Vascular Surgery/Society for Vascular Surgery, Society for Cardiovacular Angiography and Interventions, Society for Vascular Medicine and Biology, Society of Interventional Radiology, and the ACC/AHA Task Force on Practice Guidelines. Circulation. 2006; 113 (11): e463-654.
• 5. Passos VMA, Barreto SM, Guerra HL, Firmo JOA, Vidigal PG, Lima-Costa MFF. The Bambuí Health and Aging Study (BHAS): prevalence of intermittent claudication in the aged population of the community of Bambuí and its associated factors. Arq Bras Cardiol. 2001; 77: 458-62.
• 6. Guillemin F, Bombardier C, Beaton D. Cross-cultural adaptation of health-related quality of life measures: literature review and proposed guidelines. J Clin Epidemiol. 1993; 46: 1417-32.
• 7. Makdisse M. Índice tornozelo-braquial: importância e uso na prática clínica. São Paulo: Editora Segmento Farma; 2004.
• 8. Weitz JI, Byrne J, Clagett JP, Farkouh ME, Porter JM, Sackett DL. Diagnosis and treatment of chronic arterial insufficiency of the lower extremities: a critical review. Circulation. 1996; 94 (11): 3026-49.
• 9. Rose GA. The diagnosis of ischaemic heart pain and intermittent claudication in field surveys. Bull WHO. 1962;27:645-58.
• 10. Criqui MH, Fronek A, Klauber MR, Barret-Connor E, Gabriel S. The sensitivity, specificity, and predictive value of traditional clinical evaluation of peripheral arterial disease: results from noninvasive testing in a defined population. Circulation. 1985; 71: 516-22.
• 11. Leng GC, Fowkes FGR. The Edimburgh Claudication Questionnaire: an improved version of the WHO/Rose Questionnaire for use in epidemiological surveys. J Clin Epidemiol. 1992; 20: 384-92.
• 12. Aboyans V, Lacroix P, Waruingi W, Bertin F, Pesteil F, Vergnenegre A, et al. Traduction française et validation du questionnaire dEdimbourg pour le dépistage de la claudication intermittente. Arch Mal Coeur. 2000; 93: 1173-7.
• 13. Lacroix P, Aboyans V, Boissier C, Bressolette L, Leger P. Validation dune traduction française du questionnaire dEdimbourg au sein dune population de consultants en médicine génerale. Arch Mal Coeur. 2002; 95: 596-600.
• ¹⁴
  TASC Working Group. Management of Peripheral Arterial Disease (PAD): TransAtlantic Inter-Society Consensus (TASC). J Vasc Surg. 2000; 31 (1, Part 2): S1-S288.

Publication Dates

• Publication in this collection
  15 June 2007
• Date of issue
  May 2007

History

• Received
  13 July 2006
• Reviewed
  06 Nov 2006
• Accepted
  17 Jan 2007