Anna Cláudia Sentanin

Validity of the six-minute step test of free cadence in patients with chronic obstructive pulmonary disease

Objectives: to evaluate the concurrent validity of the six-minute step test (6MST) in assessing exercise capacity of COPD patients using the six-minute walk test (6MWT) as a gold-standard. The predictive validity of the 6MST was assessed to determine a cut-off point for identification of low exercise capacity. Method: thirty-two COPD patients (50-87 years old) with mild to very severe obstruction performed the 6MST and 6MWT twice. Results: Concurrent validity: a strong positive correlation (Pearson) between the number of ascents on the first (T1), second (T2) and the best of both (T1 or T2) tests during the 6MWT was observed. Although a moderate negative correlation with BODE index and FEV1 was found, it was considered insufficient to test the validity, therefore ROC curves were not applied. The predictive validity (ROC) of the 6MST to identify low physical capacity (compared with the 6MWT) using the performance of T1 or T2, or solely T1 was considered accurate, and the area under the curve was 0.8 (IC95% 0.62-0.98) and 0.85 (IC95% 0.70-0.99), respectively. To classify patients, the cut-off points of 86 and 78 steps were chosen, with both values showing 90% of sensitivity and specificity of 64% and 68% for T1 or T2, or solely T1, respectively. Conclusion: The number of steps on the 6MST was valid to verify exercise capacity in COPD patients and the cut-off point of 78 steps was able to identify patients with poor exercise tolerance. Values under this cut-off point are considered to identify patients with a poorer prognosis.

Validity and Reliability of the 6-Minute Step Test in Healthy Individuals: A Cross-sectional Study.

Objective:To determine the 6-minute step tests (6MST) reliability and validity and to establish reference performance values of this test. Design:Prospective observational cross-sectional study. Setting:Spirometry and Respiratory Physiotherapy Laboratory, Federal University of São Carlos (institutional). Participants:Ninety-one individuals [42 men and 49 women, mean age = 39 years (SD, 17 years)] without any diagnosed diseases and with normal exercise capacity [6-minute walk test (6MWT) >75% of the predicted normal]. Independent Variables:Participants underwent two 6MST on 1 day and two 6MWT on another day in randomized order. Furthermore, age, gender, height, weight, lower limbs length, abdominal circumference, percentage of body fat, and fat-free mass were obtained. Main Outcome Measures:Test–retest reliability was assessed by comparing the findings of the two 6MST using the intraclass correlation coefficient (ICC) and Bland–Altman plot. Validity was assessed by comparing outcomes of the 6MST to outcomes of 6MWT using the Pearson correlation coefficient. A multiple regression analysis was conducted using the stepwise method to develop an equation to predict reference values. Results:The performance (mean steps ± SD) in the first and second test was 149 ± 34 and 149 ± 36 steps, respectively, which was correlated to distance (in meters) in 6MWT (r = 0.72; P < 0.05). Six-minute step test performance was reliable (ICC = 0.9; 95% confidence interval: 0.85–0.93). The equation to predict reference values for the first 6MST was significant (P < 0.001 and R2 = 0.48): Performance(steps) = 174 to 1.05 × Age(years) to women and Performance(steps) = 209 to 1.05 × Age(years) to men. Conclusions:Six-minute step test is a reliable and valid test. Moreover, the number of steps may be predicted by demographic and anthropometric variables with moderate strength of prediction. Clinical Relevance:Six-minute step test is an exercise test that is easy to be conducted, more tolerable than a graded exercise test, requires fewer equipments and space, and permits better monitoring of the participants. The assessment of the reliability, validity, and reference values will provide a better interpretability for clinicians to use it, especially in primary care.

Should the 6-Minute Walk Test Be Compared When Conducted by 2 Different Assessors in Subjects With COPD?

BACKGROUND: The 6-min walk test (6MWT) is an important tool in the assessment of functional capacity and prognosis in patients with COPD. However, especially in long-term follow-up in clinical settings, this test may be executed by a different assessor, and it is not well known whether 6MWT has an acceptable inter-rater reliability. The aim of this study is to analyze the intra- and inter-rater reliability of the performance in 6MWT, its cardiorespiratory changes, and effort perception in subjects with COPD. METHODS: Thirty-two subjects with a diagnosis of COPD participated in the study, but 3 subjects did not appear on the second day of evaluation and therefore were included only in the intra-rater analysis; the first and second tests were executed by the same assessor with a 30-min interval between them, and the last was executed by a different assessor a week later. The intra-rater reliability was verified comparing the first and second 6MWT performance, and the inter-rater reliability was verified comparing the third test with the best performance of the first and second tests. RESULTS: The intraclass correlation coefficient values were >0.75 (P < .001) for the walked distance on the 6MWT; however, the limits of agreement, SE of measurement, and minimal detectable difference were higher than the minimum clinically important differences already mentioned in the literature (∼25, 26, and 54 m), and the coefficient of variation was small in both intra- and inter-rater comparisons. CONCLUSIONS: The 6MWT showed excellent reliability for distance and perceived exertion and moderate to excellent for HR and SD as assessed by intra- and inter-rater analysis. Thus, based on the main study outcomes, we concluded that the 6MWT can be compared when conducted by 2 different evaluators.

Reliability intra and inter-rater of a handheld dynamometer in COPD patients

Background: Chronic Obstructive Pulmonary Disease (COPD) patients present peripheral muscle dysfunction, which occurs mostly in quadriceps muscle and contribute to impairment on functional capacity. Therefore, the strength assessment is an important tool in this population and portable dynamometer has been used since it is low cost and accessible. It is known this equipment is a method used by different evaluators and it is important that the measures are reliable. Objective: To verify intra and inter-rater reliability of the portable dynamometer (Microfet2®Hoggan – Health Industries, West Jordan, UT, USA) to knee extension. Methods: A blind cross-sectional study, two trained evaluators assessed 19 COPD patients in two non-consecutive days. Patients were sitting on an adjustable ergonomic chair and performed a maximal knee extension for at least 4 seconds. Reliability was analyzed using the intraclass correlation coefficient (ICC), classifying the values as poor (ICC 0.4 and 0.75) (Fleiss, 1986). Results: To intra rater reliability was found ICC: 0.87 (0.68-0.95) and 0.87 (0.7-0.95) for the first evaluator and ICC: 0.88 (0.73-0.95) and 0.85 (0.66-0.94) for the second evaluator, for right and left lower limb respectively. In the inter-rater analysis was found ICC: 0.8 (0.57-0.92) and 0.83 (0.62 -0.93) for the first day; ICC 0.73 (0.43-0.89) and 0.93(0.83-0.97) for the second day for right and left lower limb respectively. Conclusion: The strength measurements showed excellent intra and inter rater reliability, which demonstrate they can be performed by different evaluators.

Reproductibilidad del test de caminata y del escalón de 6 minutos en adultos jóvenes saludables

INTRODUCAO: Os testes caminhada de seis minutos (TC6) e degrau de seis minutos (TD6) sao meios de avaliacao da capacidade funcional. No entanto, pouco se sabe sobre sua reprodutibilidade em adultos jovens.OBJETIVO: Avaliar a reprodutibilidade relativa e absoluta tanto intra quanto inter-avaliadores do TC6 e TD6 em individuos adultos jovens.METODOS: Foram avaliados 33 individuos adultos jovens aparentemente saudaveis por meio da espirometria; e realizados os testes TC6 e TD6. Tres (T1, T2 e T3) TC6 e TD6 foram feitos em cada individuo, sendo o ultimo de cada teste realizado por um avaliador diferente. Para a analise intra-avaliadores foram comparados os desempenhos do T1 e T2 enquanto que a analise inter-avaliadores foi feita pela comparacao dos desempenhos do T3 com: T1; T2; e escolha do melhor dos primeiros dois testes. Foi calculado o coeficiente de correlacao intra-classe (CCI) como medida da reprodutibilidade relativa; o erro padrao de medida; a diferenca minima detectavel; tracados graficos de Bland-Altman e teste ANOVA para analisar a reprodutibilidade absoluta.RESULTADOS: Observaram-se, nos dois testes funcionais, intra e inter-avaliadores, valores excelentes de reprodutibilidade relativa (CCI>0,75) e a reprodutibilidade absoluta mostrou alto erro.CONCLUSAO: O TD6 e o TC6 apresentaram reprodutibilidade intra e inter-avaliadores excelente para a populacao adulto jovem, mas altos valores de erro.Introduction: Six Minute Walk Test (6MWT) and Six Minute Step Test (6MST) are tests to evaluate functional capacity. However, reproducibility of these tests is still not well known in young adults. Objective: To evaluate intra and inter-rater relative and absolute reproducibility of 6MWT and 6MST in young adults. Methods: Thirty-three apparently health young adults were evaluated through spirometry, 6MWT and 6MST. Three (T1, T2 and T3) of each 6MWT and 6MST were carried out on each individual, the latter (T3) by a different evaluator. Intra-rater analysis was performed comparing the performance of T1 and T2, while the inter-rater analysis was executed using the comparisons of T3 with T1, T2 and the best result of the first two. Intra-class correlation coefficient (ICC) was calculated as a measure of relative reproducibility; the standard error of measurement, minimal detectable change, Bland-Altman plots and repeated measures ANOVA were used to verify absolute reproducibility. Results: Excellent values of relative reproducibility (ICC>0.75) were observed in both 6MWT and 6MST, yet high error values were found in absolute reproducibility analysis. Conclusion: 6MWT and 6MST present excellent intra and inter-rater relative reproducibility, but high error values.

Reproducibility of the six-minute walk and step tests in healthy young adults

INTRODUCAO: Os testes caminhada de seis minutos (TC6) e degrau de seis minutos (TD6) sao meios de avaliacao da capacidade funcional. No entanto, pouco se sabe sobre sua reprodutibilidade em adultos jovens.OBJETIVO: Avaliar a reprodutibilidade relativa e absoluta tanto intra quanto inter-avaliadores do TC6 e TD6 em individuos adultos jovens.METODOS: Foram avaliados 33 individuos adultos jovens aparentemente saudaveis por meio da espirometria; e realizados os testes TC6 e TD6. Tres (T1, T2 e T3) TC6 e TD6 foram feitos em cada individuo, sendo o ultimo de cada teste realizado por um avaliador diferente. Para a analise intra-avaliadores foram comparados os desempenhos do T1 e T2 enquanto que a analise inter-avaliadores foi feita pela comparacao dos desempenhos do T3 com: T1; T2; e escolha do melhor dos primeiros dois testes. Foi calculado o coeficiente de correlacao intra-classe (CCI) como medida da reprodutibilidade relativa; o erro padrao de medida; a diferenca minima detectavel; tracados graficos de Bland-Altman e teste ANOVA para analisar a reprodutibilidade absoluta.RESULTADOS: Observaram-se, nos dois testes funcionais, intra e inter-avaliadores, valores excelentes de reprodutibilidade relativa (CCI>0,75) e a reprodutibilidade absoluta mostrou alto erro.CONCLUSAO: O TD6 e o TC6 apresentaram reprodutibilidade intra e inter-avaliadores excelente para a populacao adulto jovem, mas altos valores de erro.Introduction: Six Minute Walk Test (6MWT) and Six Minute Step Test (6MST) are tests to evaluate functional capacity. However, reproducibility of these tests is still not well known in young adults. Objective: To evaluate intra and inter-rater relative and absolute reproducibility of 6MWT and 6MST in young adults. Methods: Thirty-three apparently health young adults were evaluated through spirometry, 6MWT and 6MST. Three (T1, T2 and T3) of each 6MWT and 6MST were carried out on each individual, the latter (T3) by a different evaluator. Intra-rater analysis was performed comparing the performance of T1 and T2, while the inter-rater analysis was executed using the comparisons of T3 with T1, T2 and the best result of the first two. Intra-class correlation coefficient (ICC) was calculated as a measure of relative reproducibility; the standard error of measurement, minimal detectable change, Bland-Altman plots and repeated measures ANOVA were used to verify absolute reproducibility. Results: Excellent values of relative reproducibility (ICC>0.75) were observed in both 6MWT and 6MST, yet high error values were found in absolute reproducibility analysis. Conclusion: 6MWT and 6MST present excellent intra and inter-rater relative reproducibility, but high error values.

Reprodutibilidade do teste de caminhada e do degrau de 6 minutos em adultos jovens saudáveis

INTRODUCAO: Os testes caminhada de seis minutos (TC6) e degrau de seis minutos (TD6) sao meios de avaliacao da capacidade funcional. No entanto, pouco se sabe sobre sua reprodutibilidade em adultos jovens.OBJETIVO: Avaliar a reprodutibilidade relativa e absoluta tanto intra quanto inter-avaliadores do TC6 e TD6 em individuos adultos jovens.METODOS: Foram avaliados 33 individuos adultos jovens aparentemente saudaveis por meio da espirometria; e realizados os testes TC6 e TD6. Tres (T1, T2 e T3) TC6 e TD6 foram feitos em cada individuo, sendo o ultimo de cada teste realizado por um avaliador diferente. Para a analise intra-avaliadores foram comparados os desempenhos do T1 e T2 enquanto que a analise inter-avaliadores foi feita pela comparacao dos desempenhos do T3 com: T1; T2; e escolha do melhor dos primeiros dois testes. Foi calculado o coeficiente de correlacao intra-classe (CCI) como medida da reprodutibilidade relativa; o erro padrao de medida; a diferenca minima detectavel; tracados graficos de Bland-Altman e teste ANOVA para analisar a reprodutibilidade absoluta.RESULTADOS: Observaram-se, nos dois testes funcionais, intra e inter-avaliadores, valores excelentes de reprodutibilidade relativa (CCI>0,75) e a reprodutibilidade absoluta mostrou alto erro.CONCLUSAO: O TD6 e o TC6 apresentaram reprodutibilidade intra e inter-avaliadores excelente para a populacao adulto jovem, mas altos valores de erro.Introduction: Six Minute Walk Test (6MWT) and Six Minute Step Test (6MST) are tests to evaluate functional capacity. However, reproducibility of these tests is still not well known in young adults. Objective: To evaluate intra and inter-rater relative and absolute reproducibility of 6MWT and 6MST in young adults. Methods: Thirty-three apparently health young adults were evaluated through spirometry, 6MWT and 6MST. Three (T1, T2 and T3) of each 6MWT and 6MST were carried out on each individual, the latter (T3) by a different evaluator. Intra-rater analysis was performed comparing the performance of T1 and T2, while the inter-rater analysis was executed using the comparisons of T3 with T1, T2 and the best result of the first two. Intra-class correlation coefficient (ICC) was calculated as a measure of relative reproducibility; the standard error of measurement, minimal detectable change, Bland-Altman plots and repeated measures ANOVA were used to verify absolute reproducibility. Results: Excellent values of relative reproducibility (ICC>0.75) were observed in both 6MWT and 6MST, yet high error values were found in absolute reproducibility analysis. Conclusion: 6MWT and 6MST present excellent intra and inter-rater relative reproducibility, but high error values.