Table 3.
Prediction of Mortality According to Baseline Fast Walking Speed (FWS) and Change in FWS
| Model* | Baseline FWS | Change in FWS (Cont) | Change in FWS (categorical)† | ||
|---|---|---|---|---|---|
| Normal Change | Small Decline | Substantial Decline | |||
| HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | |
| Full follow-up period (n = 2,094; 308 deaths) | |||||
| M1: age, sex, baseline FWS (Cont) | 0.79 (0.70, 0.90) | — | — | — | — |
| M2: M1 + change in FWS (Cont) | 0.71 (0.62, 0.82) | 0.80 (0.71, 0.90) | — | — | — |
| M3: M1 + change in FWS (Cat1)† | 0.76 (0.66, 0.86) | — | 1.00 (ref) | 1.18 (0.89, 1.57) | 1.40 (1.02, 1.92) |
| M3: M1 + change in FWS (Cat2)‡ | 0.75 (0.66, 0.85) | — | 1.00 (ref) | 1.24 (0.94, 1.65) | 1.94 (1.22, 3.11) |
| Four first years of follow-up (n = 2,094; 93 deaths) | |||||
| M1: age, sex, baseline FWS (Cont) | 0.81 (0.65, 1.03) | — | — | — | — |
| M2: M1 + change in FWS (Cont) | 0.72 (0.56, 0.92) | 0.77 (0.63, 0.94) | — | — | — |
| M3: M1 + change in FWS (Cat1)† | 0.74 (0.58, 0.94) | — | 1.00 (ref) | 1.53 (0.93, 2.54) | 2.05 (1.19, 3.53) |
| M3: M1 + change in FWS (Cat2)‡ | 0.74 (0.59, 0.94) | — | 1.00 (ref) | 1.62 (1.00, 2.63) | 2.49 (1.15, 5.39) |
| Excluding the four first years of follow-up (n = 1,921; 215 deaths) | |||||
| M1: Age, sex, baseline FWS (Cont) | 0.78 (0.67, 0.91) | — | — | — | — |
| M2: M1 + change in FWS (Cont) | 0.71 (0.60, 0.83) | 0.81 (0.71, 0.93) | — | — | — |
| M3: M1 + change in FWS (Cat1)† | 0.77 (0.65, 0.90) | — | 1.00 (ref) | 1.05 (0.74, 1.49) | 1.17 (0.79, 1.73) |
| M3: M1 + change in FWS (Cat2)‡ | 0.75 (0.64, 0.88) | — | 1.00 (ref) | 1.10 (0.77, 1.56) | 1.73 (0.96, 3.11) |
Notes: CI = confidence interval; Cont = continuous; Cat = categorical; M = model; HR = hazards ratio; ref = reference. *Continuous variables are standardized: the HR for baseline FWS corresponds to an increment of 0.299 m/s; the HR for FWS change corresponds to an increase in 1 y change FWS of 0.065 m/s.
†Categorical definition 1 (Cat1) of annual change in FWS: substantial decline: <−0.08 m/s; small decline: −0.08 to −0.04 m/s; normal: ≥−0.04 m/s.
‡Categorical definition 2 (Cat2) of annual change in FWS: substantial decline: <−0.14 m/s; small decline: −0.06 to −0.14 m/s; normal: ≥−0.06 m/s.
§ p value comparing the predictive values of M2/M3 with M1.