Table 1. Baseline Characteristics of Patients With MG and Matched Controls.
| Characteristic | Patients with MG (n = 4411) | General population controls (n = 22 055) | Standardized differencea | Controls wth RA (n = 22 055) | Standardized differencea |
|---|---|---|---|---|---|
| Age, mean (SD), y | 67.7 (15.6) | 67.7 (15.6) | 0 | 67.7 (15.6) | 0 |
| Sex, No. (%) | |||||
| Female | 2274 (51.6) | 11 370 (51.6) | 0 | 11 370 (51.6) | 0 |
| Male | 2137 (48.4) | 10 685 (48.4) | 0 | 10 685 (48.4) | 0 |
| Urban residence, No. (%) | 3901 (88.4) | 19 585 (88.8) | 0.01 | 19 276 (87.4) | 0.03 |
| Area income quintile, No. (%) | |||||
| First (lowest) | 938 (21.3) | 4371 (19.8) | 0.04 | 4338 (19.7) | 0.04 |
| Second | 861 (19.5) | 4315 (19.6) | 0 | 4475 (20.3) | 0.02 |
| Third | 901 (20.4) | 4419 (20.0) | 0.01 | 4411 (20.0) | 0.01 |
| Fourth | 808 (18.3) | 4292 (19.5) | 0.03 | 4231 (19.2) | 0.02 |
| Fifth (highest) | 886 (20.1) | 4591 (20.8) | 0.02 | 4521 (20.5) | 0.01 |
| Area ethnic diversity quintile, No. (%) | |||||
| First (lowest) | 849 (19.2) | 4165 (18.9) | 0.01 | 4403 (20) | 0.02 |
| Second | 751 (17.0) | 3890 (17.6) | 0.02 | 4319 (19.6) | 0.07 |
| Third | 794 (18.0) | 4033 (18.3) | 0.01 | 4111 (18.6) | 0.02 |
| Fourth | 906 (20.5) | 4305 (19.5) | 0.03 | 4189 (19) | 0.04 |
| Fifth (highest) | 1067 (24.2) | 5503 (25.0) | 0.02 | 4804 (21.8) | 0.06 |
| Chronic comorbidities, No. (%) | |||||
| Asthma | 899 (20.4) | 2929 (13.3) | 0.19 | 4341 (19.7) | 0.02 |
| Congestive heart failure | 539 (12.2) | 1661 (7.5) | 0.16 | 2369 (10.7) | 0.05 |
| Chronic pulmonary obstructive disease | 1001 (22.7) | 3699 (16.8) | 0.15 | 5170 (23.4) | 0.02 |
| Hypertension | 2712 (61.5) | 12 130 (55.0) | 0.13 | 13 297 (60.3) | 0.02 |
| Diabetes | 1380 (31.3) | 5493 (24.9) | 0.14 | 5949 (27.0) | 0.10 |
| Charlson Comorbidity Index score (past 5 y), No. (%) | |||||
| Mean (SD), No. | 0.8 (1.4) | 0.5 (1.1) | 0.25 | 0.7 (1.4) | 0.06 |
| 0 | 2976 (67.5) | 17 568 (79.7) | 0.28 | 15 366 (69.7) | 0.06 |
| 1 | 498 (11.3) | 1808 (8.2) | 0.10 | 2866 (13.0) | 0.05 |
| 2 | 477 (10.8) | 1422 (6.4) | 0.16 | 1805 (8.2) | 0.05 |
| ≥3 | 460 (10.4) | 1257 (5.7) | 0.17 | 2018 (9.1) | 0.09 |
| Residence in long-term care, No. (%) | 170 (3.9) | 550 (2.5) | 0.08 | 615 (2.8) | 0.06 |
Abbreviations: MG, myasthenia gravis; RA, rheumatoid arthritis.
a
Standardized difference of 0.1 or less indicates a good balance of variables.