Predictors of 6-Minute Walk Distance Among Aging Adults With Chronic Cardiopulmonary, Metabolic, and Renal Diseases

Background The 6-minute walk test is a widely used measure of physical function in healthy people and patients with chronic conditions. Few reports have compared 6-minute walk distance (6MWD) across different conditions, and limited knowledge is available about how common covariates [age, sex, body mass index (BMI)] differentially affect 6MWD. Our purposes were to examine the 6MWD in persons with chronic conditions, compare walk distances with healthy controls, and identify predictors of 6MWD. Methods Data were aggregated from previous studies. Participants with primary diagnoses of heart failure (HF), chronic obstructive pulmonary disease (COPD), type 2 diabetes, chronic kidney disease, and peripheral artery disease (PAD) were included. Univariate and multivariate general linear models were used to estimate the impact of each condition on the 6MWD. Results The sample included 429 adults (48% female) aged 63 ± 9 years. Participants with HF, COPD, and PAD walked shorter distances than healthy controls (all P < 0.01). Predictors differed by group. In the HF group, age, Black race, and male sex negatively affected 6MWD. In the type 2 diabetes group, older age and high BMI were associated with shorter distances walked. In the chronic kidney disease group, higher BMI, Black race, and male sex negatively impacted 6MWD. No covariates were associated with 6MWD in the PAD, COPD, or control groups. Conclusion We found wide variation in common, nondisease-specific predictors of the 6MWD and significantly lower 6MWDs compared with healthy controls. Our findings add to our knowledge of 6MWD among aging adults with common chronic diseases.