Longitudinal evaluation of the one-minute sit-to-stand test in fibrosing interstitial lung diseases: association with the six-minute walk test and patient outcomes

Functional capacity and exercise-induced gas exchange impairment are important prognostic markers in fibrosing interstitial lung diseases. The six-minute walk test is routinely used to assess functional exercise capacity in this population. The one-minute sit-to-stand test has been proposed as a feasible alternative functional assessment in clinical practice that is less time-consuming and does not require a 100-foot corridor. Prospective longitudinal data in fibrosing interstitial lung diseases remain limited. We evaluated the longitudinal relationship between the one-minute sit-to-stand test and the six-minute walk test performance. We explored associations between the one-minute sit-to-stand test and clinical outcomes in fibrosing interstitial lung diseases. We performed a single-center prospective cohort study of patients with confirmed fibrosing interstitial lung disease who completed pulmonary function testing and the six-minute walk test. Participants performed one-minute sit-to-stand test at baseline and at 6- and 12-month follow-up. Associations between the one-minute sit-to-stand test repetitions and six-minute walk distance were assessed using correlation analyses. Longitudinal associations were analyzed using linear mixed-effects models. Logistic regression was used to examine associations between the one-minute sit-to-stand test performance and 12-month mortality. A total of 100 patients were included. One-minute sit-to-stand test repetitions were moderately associated with six-minute walk distance at baseline ( r = 0.56), 6 months ( r = 0.64), and 12 months ( r = 0.58), and with Forced Vital Capacity (% predicted) across all time points ( r = 0.40–0.41). In mixed-effects models, higher one-minute sit-to-stand test repetitions were associated with greater six-minute walk distance (β = 19.16 feet per repetition, 95% CI 11.86–26.56). Higher one-minute sit-to-stand test performance was associated with lower 12-month mortality (OR = 0.72, 95% CI 0.50–0.93). The one-minute sit-to-stand test performance demonstrates a consistent moderate longitudinal association with six-minute walk test performance and lung function in fibrosing interstitial lung diseases and is associated with 12-month mortality. The one-minute sit-to-stand test may represent a useful alternative functional assessment in fibrosing interstitial lung diseases.