This study examined whether the six-minute walk test (6MWT) and handgrip strength (HGS) can accurately assess cardiorespiratory fitness (CRF) — measured as VO2peak by cardiopulmonary exercise testing — in 80 adults with psoriatic arthritis (PsA).
Six-minute walk distance (6MWD) was strongly correlated with VO2peak (rS = 0.65, P < 0.001), and a multivariable model combining 6MWD with 6MWT heart rate response explained 70% of VO2peak variance; a threshold of 108% predicted 6MWD detected impaired CRF with 75% sensitivity and 64% specificity. HGS showed no meaningful association with VO2peak or key clinical outcomes.
The sample was limited to 80 patients, which may restrict generalizability. The 64% specificity of the 6MWD threshold indicates a meaningful false-positive rate. Neither 6MWD nor HGS were significantly lower than general population norms, raising questions about whether this PsA cohort was representative of the broader, potentially more impaired population.
Clinicians can use the six-minute walk test as a practical, office-based tool to screen for impaired cardiorespiratory fitness in PsA patients — a 6MWD below 108% of predicted value should prompt further evaluation. Handgrip strength does not add useful information for CRF assessment in this population.
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