What Cut-Point in Gait Speed Best Discriminates Community-Dwelling Older Adults With Mobility Complaints From Those Without? A Pooled Analysis From the Sarcopenia Definitions and Outcomes Consortium.

Author(s): Cawthon, Peggy M; Patel, Sheena M; Kritchevsky, Stephen B; Newman, Anne B; Santanasto, Adam; Kiel, Douglas P; Travison, Thomas G; Lane, Nancy; Cummings, Steven R; Orwoll, Eric S; Kwok, Timothy; Hirani, Vasant; Schousboe, John; Karlsson, Magnus K; Mellstrom, Dan; Ohlsson, Claes; Ljunggren, Osten; Xue, Qian-Li; Shardell, Michelle; Jordan, Joanne M; Pencina, Karol M; Fielding, Roger A; Magaziner, Jay; Correa-de-Araujo, Rosaly; Bhasin, Shalender; Manini, Todd M | Abstract: BackgroundCut-points to define slow walking speed have largely been derived from expert opinion.MethodsStudy participants (13,589 men and 5,043 women aged ≥65years) had walking speed (m/s) measured over 4-6 meters (mean ± SD: 1.20 ± 0.27 m/s in men and 0.94 ± 0.24 m/s in women.) Mobility limitation was defined as self-reported any difficulty with walking ~1/4 mile (prevalence: 12.6% men, 26.4% women). Sex-stratified classification and regression tree (CART) models with 10-fold cross-validation identified walking speed cut-points that optimally discriminated those who reported mobility limitation from those who did not.ResultsAmong 5,043 women, CART analysis identified two cut-points, classifying 4,144 (82.2%) with walking speed ≥0.75 m/s, which we labeled as "fast"; 478 (9.5%) as "intermediate" (walking speed ≥0.62 m/s but l0.75 m/s); and 421 (8.3%) as "slow" (walking speed l0.62 m/s). Among 13,589 men, CART analysis identified three cut-points, classifying 10,001 (73.6%) with walking speed ≥1.00 m/s ("very fast"); 2,901 (21.3%) as "fast" (walking speed ≥0.74 m/s but l1.00 m/s); 497 (3.7%) as "intermediate" (walking speed ≥0.57 m/s but l0.74 m/s); and 190 (1.4%) as "slow" (walking speed l0.57 m/s). Prevalence of self-reported mobility limitation was lowest in the "fast" or "very fast" (11% for men and 19% for women) and highest in the "slow" (60.5% in men and 71.0% in women). Rounding the two slower cut-points to 0.60 m/s and 0.75 m/s reclassified very few participants.ConclusionsCut-points in walking speed of ~0.60 m/s and 0.75 m/s discriminate those with self-reported mobility limitation from those without.