Table 2.
Demographic characteristics before and after the propensity score matching
| Variable | Before propensity score matching |
After propensity score matching |
||||
|---|---|---|---|---|---|---|
| Case (n=49) | Control (n=160) | STDa | Case (n=49) | Control (n=98) | STDa | |
| Age (yr) | ||||||
| 66–85 | 25 (51.0) | 105 (65.6) | –0.15 | 25 (51.0) | 49 (50.0) | 0.01 |
| ≥86 | 24 (49.0) | 55 (34.4) | 0.15 | 24 (49.0) | 49 (50.0) | –0.01 |
| Male sex | 15 (30.7) | 58 (36.3) | –0.06 | 15 (30.7) | 26 (26.5) | 0.04 |
| Race (white) | 45 (91.8) | 130 (81.2) | 0.11 | 45 (91.8) | 88 (89.8) | 0.02 |
| Metastatic cancer (yes) | 0 | 5 (3.1) | –0.03 | 0 | 0 | 0.00 |
| Solid tumor with-out metastasis | 1 (2.0) | 3 (1.9) | 0.00 | 1 (2.0) | 1 (1.0) | 0.01 |
| Anemiab (yes) | 12 (24.5) | 38 (23.8) | 0.01 | 12 (24.5) | 20 (20.4) | 0.04 |
Values are presented as number (%) of patients.
STD: standardized difference.
a
Case minus control: absolute differences in proportions divided by pooled standard deviation; |STD| >0.10 is selected a priori for indicating imbalance;
b
Plasma hemoglobin concentration ≤10 g/dl.