Table 1.
Demographic Characteristics of the Study Population and Matched Cohorts
| Characteristic | No. (%) | Matched cohorts for each CDI case definition | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| ||||||||||||||||
| i. by ICD-9 code | ii. by EIA (+) | iii. by PCR (+) | iv. by EIA or PCR (+) | v. by any of the criteria | ||||||||||||
|
| ||||||||||||||||
| No. (%) | SMD after matching (P value) |
No. (%) | SMD after matching (P value) |
No. (%) | SMD after matching (P value) |
No. (%) | SMD after matching (P value) |
No. (%) | SMD after matching (P value) |
|||||||
|
|
|
|
|
|
||||||||||||
| All patients (n=171 936) |
All controls (n=171 356) |
Matched cases & controlsa (n=489) |
All controls (n= 73 647) |
Matched cases & controlsa (n=274) |
All controls (n=97 351) |
Matched cases & controlsa (n=493) |
All controls (n=170 994) |
Matched cases & controlsa (n=788) |
All controls (n=170 846) |
Matched cases & controlsa (n=945) |
||||||
| Female sex | 101 964 (59) | 101 638 (59) | 278 (57) | 0 (1) | 44 132 (60) | 145 (53) | 0 (1) | 57 340 (59) | 254 (52) | 0 (1) | 101 469 (59) | 408 (52) | 0 (1) | 101 390 (59) | 493 (52) | 0 (1) |
| Ageb | ||||||||||||||||
| 18–29 | 22 344 (13) | 22 266 (13) | 69 (14) | 0.016 (0.86) | 9 552 (13) | 22 (8) | 0.018 (0.79) | 12 714 (13) | 47 (10) | 0.005 (0.99) | 22 265 (13) | 79 (9) | 0.003 (0.98) | 22 245 (13) | 87 (9) | 0.004 (0.93) |
| 30–44 | 39 003 (23) | 38 898 (23) | 86 (18) | 16 451 (22) | 26 (9) | 22 430 (23) | 72 (15) | 38 879 (23) | 124 (13) | 38 845 (23) | 134 (14) | |||||
| 45–59 | 37 234 (22) | 37 129 (22) | 90 (18) | 15 956 (22) | 58 (21) | 21 069 (22) | 117 (24) | 37 025 (22) | 209 (23) | 36 999 (22) | 208 (22) | |||||
| 60–74 | 43 946 (26) | 43 802 (26) | 122 (25) | 18 407 (25) | 83 (30) | 25 273 (26) | 136 (28) | 43 680 (26) | 266 (29) | 43 643 (26) | 267 (28) | |||||
| 75–90 | 26 167 (15) | 26 041 (15) | 106 (22) | 11 817 (16) | 70 (26) | 14 120 (15) | 114 (23) | 25 936 (15) | 231 (24) | 25 912 (15) | 217 (23) | |||||
| ≥90 | 3 244 (2) | 3 220 (2) | 16 (3) | 1 464 (2) | 15 (5) | 1 745 (2) | 7 (1) | 3 209 (2) | 35 (3) | 3 202 (2) | 32 (3) | |||||
Abbreviation: CDI, Clostridium difficile infection; ICD-9, International Classification of Diseases Ninth Revision; EIA, enzyme immunoassay; PCR, polymerase chain reaction; SMD, standardized mean difference.
a
Separate columns are unnecessary because 1:1 exact matching was performed on the characteristics shown, and therefore all values are identical.
b
SMD is shown for age treated as a continuous variable; coarsened exact matching was performed using the listed age ranges.