Reference values and regression equations for predicting the 6-minute walk distance in Saudi adults aged 50–80 years: A cross- sectional study

Abstract

BACKGROUND: The 6-minute walk test (6-MWT) is commonly used to measure functional capacity in clinical and research settings. The reference equations for predicting the 6-minute walk distance (6-MWD) in different populations have been established; however, there is a lack of information regarding healthy Saudi individuals over 50 years old. OBJECTIVES: This study aimed to establish the reference values of 6-MWD in a sample of healthy Saudi adults aged 50–80 years, develop regression equations for the established 6-MWD, and compare the measured 6-MWD in the present study with the predicted 6-MWD derived from the previously published regression equations. METHODS: In total, 210 healthy Saudi volunteers aged 50–80 years participated in this cross-sectional study. The 6-MWT was performed according to the American Thoracic Society (ATS) guidelines. Lung function, physical activity, blood pressure, heart rate, oxygen saturation, exertion level of leg fatigue, and sensation of dyspnea were measured. RESULTS: The mean 6-MWD was 396.2 ± 69.4 m. It was significantly correlated with age, sex, height, body mass index (BMI), and physical activity. The predictors of 6-MWD were age and BMI for men, while they were age, BMI, and height for women. They accounted for 25% and 35% of the total variance of 6-MWD for men and women, respectively. The measured 6-MWD was significantly shorter than the predicted 6-MWD. CONCLUSION: Saudi populations have significantly shorter 6-MWDs than those reported in other ethnic groups. The sex-specific equations developed in this study are expected to provide a useful measure of 6-MWT for Saudi adults. However, further investigation is required to validate the application of these equations to individuals living in different regions of Saudi Arabia.