Clinical determinants of the modified incremental step test in adults with non-cystic fibrosis bronchiectasis.

OBJECTIVES: This study primarily aimed to investigate the clinical determinants of the Modified Incremental Step Test (MIST) in adults with non-cystic fibrosis bronchiectasis (NCFB). A secondary objective was to compare the cardiopulmonary responses after the MIST and Incremental Shuttle Walk Test (ISWT), two commonly adopted symptom-limited maximum field tests in chronic respiratory diseases. METHODS: Forty-six patients with clinically stable bronchiectasis participated in this cross-sectional study. MIST and ISWT were performed to determine exercise capacity, while disease severity, fatigue, and quality of life were assessed using the Bronchiectasis Severity Index (BSI), the Fatigue Severity Scale (FSS), and St. George's Respiratory Questionnaire (SGRQ), respectively. Quadriceps muscle strength was evaluated using a hand-held dynamometer, walking speed with a wireless inertial sensing device, and the level of physical activity (steps/day) with a pedometer. RESULTS: The BSI score, quadriceps muscle strength, daily step count, and the SGRQ total score explained 61.9% of the variance in the MIST (p < 0.001, R2 = 0.67, AR2 = 0.619). The BSI score (r = -0.412, p = 0.004), quadriceps muscle strength (r = 0.574, p = 0.001), daily step count (r = 0.523, p < 0.001), walking speed (r = 0.402, p = 0.006), FSS score (r = -0.551, p < 0.001), and SGRQ total score (r = -0.570, p < 0.001) correlated with the MIST. The patients achieved higher heart rates (HR), HR%, desaturation, dyspnea, and leg fatigue in the MIST compared to the ISWT (p < 0.05). CONCLUSIONS: Disease severity, quadriceps muscle strength, physical activity level, and quality of life were determinants of MIST. The advantages of the MIST, including higher cardiopulmonary response than ISWT and greater portability, which facilitates its use in various settings, make MIST the preferred choice for investigating symptom-limited exercise capacity in patients with NCFB.

Clinical determinants of the modified incremental step test in adults with non-cystic fibrosis bronchiectasis / Determinantes clínicos do teste do degrau incremental modificado em adultos com bronquiectasia não fibrocística

ABSTRACT Objectives: This study primarily aimed to investigate the clinical determinants of the Modified Incremental Step Test (MIST) in adults with non-cystic fibrosis bronchiectasis (NCFB). A secondary objective was to compare the cardiopulmonary responses after the MIST and Incremental Shuttle Walk Test (ISWT), two commonly adopted symptom-limited maximum field tests in chronic respiratory diseases. Methods: Forty-six patients with clinically stable bronchiectasis participated in this cross-sectional study. MIST and ISWT were performed to determine exercise capacity, while disease severity, fatigue, and quality of life were assessed using the Bronchiectasis Severity Index (BSI), the Fatigue Severity Scale (FSS), and St. George's Respiratory Questionnaire (SGRQ), respectively. Quadriceps muscle strength was evaluated using a hand-held dynamometer, walking speed with a wireless inertial sensing device, and the level of physical activity (steps/day) with a pedometer. Results: The BSI score, quadriceps muscle strength, daily step count, and the SGRQ total score explained 61.9% of the variance in the MIST (p < 0.001, R2 = 0.67, AR2 = 0.619). The BSI score (r = -0.412, p = 0.004), quadriceps muscle strength (r = 0.574, p = 0.001), daily step count (r = 0.523, p < 0.001), walking speed (r = 0.402, p = 0.006), FSS score (r = -0.551, p < 0.001), and SGRQ total score (r = -0.570, p < 0.001) correlated with the MIST. The patients achieved higher heart rates (HR), HR%, desaturation, dyspnea, and leg fatigue in the MIST compared to the ISWT (p < 0.05). Conclusions: Disease severity, quadriceps muscle strength, physical activity level, and quality of life were determinants of MIST. The advantages of the MIST, including higher cardiopulmonary response than ISWT and greater portability, which facilitates its use in various settings, make MIST the preferred choice for investigating symptom-limited exercise capacity in patients with NCFB.

RESUMO Objetivos: Este estudo teve como objetivo principal investigar os determinantes clínicos do Teste do Degrau Incremental Modificado (TDIM) em adultos com bronquiectasia não fibrocística (BNFC). Um objetivo secundário foi comparar as respostas cardiopulmonares após o TDIM e o Teste Graduado de Caminhada (TGC), dois testes de campo máximos amplamente adotados e limitados por sintomas em doenças respiratórias crônicas. Métodos: Quarenta e seis pacientes com bronquiectasia clinicamente estável participaram deste estudo transversal. O TDIM e TGC foram realizados para determinar a capacidade de exercício, enquanto a gravidade da doença, fadiga e qualidade de vida foram avaliadas usando o Índice de Gravidade da Bronquiectasia (BSI), a Escala de Gravidade da Fadiga (FSS) e o Questionário Respiratório de Saint George (SGRQ), respectivamente. A força muscular do quadríceps foi avaliada usando um dinamômetro manual, a velocidade de caminhada com um dispositivo de sensor inercial sem fio e o nível de atividade física (passos/dia) com um pedômetro. Resultados: O escore BSI, a força muscular do quadríceps, a contagem diária de passos e o escore total do SGRQ explicaram 61,9% da variação no TDIM (p < 0,001, R2 = 0,67, AR2 = 0,619). O escore BSI (r = -0,412, p = 0,004), a força muscular do quadríceps (r = 0,574, p = 0,001), a contagem diária de passos (r = 0,523, p < 0,001), a velocidade de caminhada (r = 0,402, p = 0,006), o escore FSS (r = -0,551, p < 0,001) e o escore total do SGRQ (r = -0,570, p < 0,001) correlacionaram-se com o TDIM. Os pacientes atingiram maiores frequências cardíacas (FC), FC%, dessaturação, dispneia e fadiga nas pernas no TDIM em comparação com o TGC (p < 0,05). Conclusões: A gravidade da doença, a força muscular do quadríceps, o nível de atividade física e a qualidade de vida foram determinantes do TDIM. As vantagens do TDIM, incluindo uma resposta cardiopulmonar mais elevada que no TGC e maior portabilidade, que facilita sua utilização em diversos ambientes, fazem do TDIM a escolha preferencial para investigar a capacidade de exercício limitada por sintomas em pacientes com BNFC.