Baseline characteristics of patients.
| Characteristicsa | Men(N = 34,020) | Women(N = 36,313) | P Value of Difference |
| Age, y, mean (SD) | 55.44 (11.25) | 57.16 (11.42) | <0.001 |
| Race, n (%) | |||
| White/Caucasian | 26,085 (76.68) | 27,235 (75.00) | <0.001 |
| Black/African American | 4293 (12.62) | 2656 (7.31) | |
| Other | 3642 (10.71) | 6422 (17.69) | |
| Insurance coverage, n (%) | |||
| Medicare | 10,501 (30.87) | 13,227 (36.42) | <0.001 |
| Medicaid | 2416 (7.10) | 5433 (14.96) | |
| Private insurance | 13,330 (39.18) | 16,640 (45.82) | |
| History of, n (%) | |||
| Cancer | 0 (0.00) | 1041 (2.87) | <0.001 |
| Chronic kidney disease | 140 (0.88) | 305 (1.48) | <0.001 |
| Chronic obstructive pulmonary disease | 1618 (4.76) | 0 (0.00) | <0.001 |
| Congestive heart failure | 100 (0.29) | 0 (0.00) | <0.001 |
| Coronary artery disease | 1707 (10.72) | 246 (1.19) | <0.001 |
| Current antibiotic use | 495 (1.46) | 1083 (2.98) | <0.001 |
| Depression | 8675 (25.50) | 15,107 (41.60) | <0.001 |
| Diabetes mellitus | 599 (3.31) | 2469 (15.73) | <0.001 |
| Hypertension | 9907 (29.12) | 9761 (26.88) | <0.001 |
| Substance abuse/dependence | 2623 (16.47) | 0 (0.00) | <0.001 |
aPercentages calculated from number of patients for whom value for particular variable was known.