Table 1.
Top-Ranking Variables That Best Predicted Mortality Over 13 Years in the Full Health ABC Cohort (n=3,067)
| Variable | Transformation | Mean AUC | SD (AUC) |
|---|---|---|---|
| DSST score (number of correct substitutions) a | λ=2 | 0.599 | 0.024 |
| Serum cystatin C (mg/L) b | λ=0 | 0.587 | 0.021 |
| Health ABC performance score (0– 4) c | λ=2 | 0.578 | 0.023 |
| 3MS score a | λ=2 | 0.575 | 0.020 |
| Serum creatinine (mg/dL) b | λ=0 | 0.573 | 0.021 |
| Chronological age at baseline exam | None | 0.566 | 0.023 |
| Time to walk 6 m (fastest of two trials) c | λ=–1 | 0.565 | 0.023 |
| Full standing balance test time 0–90 sec c | λ=2 | 0.565 | 0.023 |
| Pack-years exposure to cigarettes | λ=0 | 0.564 | 0.023 |
| EPESE performance battery score 0–12 c | λ=2 | 0.563 | 0.022 |
The table lists 10 variables that best predicted mortality as identified from the data mining and cross-validation procedure described in Supplemental Fig. 2. For each variable, the mean area under the curve (AUC) from the highest-ranking vector associated with that variable is listed. Data vectors for each variable were generated using Box–Cox transformations (see Methods). The “transformation” column indicates the Box–Cox parameter that yielded the highest-scoring mean AUC listed for each variable. If the highest-scoring vector for a given variable was an untransformed variable on its original scale, then “None” is listed in the transformation column. All mean AUC values were calculated using 30,000 cross-validation trials, with a standard error less than 0.001 in each case. The standard deviation (SD) among AUC statistics generated in the 30,000 simulation trials is listed for each variable in the final column.
Digit Symbol Substitution Test (DSST) score (number of correct substitutions) was correlated with the Modified Mini-Mental State (3MS) score (rs=0.59; p<0.001).
Serum cystatin C was correlated with serum creatinine (rs=0.57; p<0.001).
Health, Aging, and Body Composition Study (Health ABC) performance score was correlated with full standing balance test time (rs=0.76), time taken to walk 6 m (rs=−0.70), and Established Populations for Epidemiological Study of the Elderly (EPESE) performance battery score (rs=0.69) (p<0.001 for each variable).