Predictive equation for six-minute walk test in Indian children, adolescents, and adults

Background: Post-COVID residual dysfunction has been observed in a majority of people, with reduction in cardiopulmonary endurance emerging as a primary symptom. The Six-Minute Walk Test is a simple, reliable, and valid test that is used routinely on people with chronic respiratory dysfunction. In the current COVID-19 pandemic situation, reference values and a predictive equation developed from a large sample across a large age group, from 6 to 75 years, will enable one to establish goals of treatment for post-COVID rehabilitation. Methods: Following institutional ethical clearance, we recruited 1369 participants for the study (685 females and 684 males). Participants were classified according to biological age into group 1 (6-12 years), group 2 (13-17 years), group 3 (18-40 years), group 4 (41-65 years), and group 5 (>65 years). Informed consent was sought and participants were screened using a health history questionnaire. Demographic features, namely, age, height, weight, and body mass index (BMI) were noted. The Six-Minute Walk Test was administered as per ATS guidelines. Clinical parameters, namely, pulse rate, respiratory rate, systolic blood pressure, diastolic blood pressure, and rate of perceived exertion were recorded. Results: The Six-Minute Walk Test (6MWT) was significantly influenced by age and gender (r = 0.257, P = 0.00 and r = 0.501, P = 0.00, respectively). Walking distance was longest in 13-17-year-old males, whereas females demonstrated a linear decline after 12 years. In each age group, males walked a greater distance than females. Stepwise linear regression analysis was used to derive the following predictive equation: 6MWT = 491.93 - (2.148 x age) + (107.07 x gender) (females = 0, males = 1). Conclusion: The study confirmed variability of the Six-Minute Walk Test, with age and gender being predominant predictors. Reference values, equations, and percentile charts generated from the study can be utilised to guide clinical decision-making while exercise prescription for patients with post COVID dysfunction.