Table 2. Mortality Rates Stratified by Age and RDW Elevation at Admission.
| Age group, y | Normal RDW | Elevated RDWa | P value | Risk ratio (95% CI)b | ||
|---|---|---|---|---|---|---|
| No. | Mortality, % | No. | Mortality, % | |||
| <50 | 341 | 1 | 65 | 8 | .003 | 5.25 (4.04-6.46) |
| 50-59 | 256 | 8 | 63 | 24 | <.001 | 2.90 (2.30-3.51) |
| 60-69 | 226 | 8 | 104 | 30 | <.001 | 3.96 (3.42-4.51) |
| 70-79 | 182 | 23 | 113 | 33 | .05 | 1.45 (1.08-1.83) |
| ≥80 | 168 | 29 | 123 | 46 | .003 | 1.59 (1.29-1.90) |
| Entire cohort | 1173 | 11 | 468 | 31 | <.001 | 2.73 (2.52-2.94) |
Abbreviation: RDW, red blood cell distribution width.
a
Elevated RDW was considered to be greater than 14.5%.
b
Risk ratios were statistically significantly different (P < .001) from each other (on the basis of a Mantel-Haenszel test), suggesting that patients younger than 70 years had higher risk ratios.