Table 1.
Demographic and clinical characteristics of SLE and non-SLE patients.
| Before matching | Postmatching | |||||
|---|---|---|---|---|---|---|
| SLE patients | Non-SLE patients | Standardized difference† | SLE patients | Non-SLE patients | Standardized difference† | |
| N | 14,777 | 341,182 | 14,262 | 14,262 | ||
| Female | 92.8% | 66.9% | 68.2 | 92.6% | 92.4% | 0.6 |
| Mean age (SD) | 45.4 (14.3) | 48.3 (20.4) | −16.6 | 45.4 (14.4) | 48.0 (14.9) | −17.5 |
| Insurance plan type: fee for service | 70.6% | 69.7% | 2 | 70.5% | 72.3% | −3.9 |
| Medicare dual eligibility | 39.7% | 39.8% | −0.2 | 39.6% | 43.2% | −7.4 |
| Race | ||||||
| White | 39.1% | 41.1% | −4.2 | 39.4% | 40.6% | −2.4 |
| Black | 36.6% | 21.0% | 35 | 36.1% | 34.6% | 3.2 |
| Hispanic | 11.4% | 21.6% | −27.8 | 11.5% | 10.7% | 2.7 |
| Other/missing | 13.0% | 16.3% | −9.4 | 13.0% | 14.2% | −3.5 |
| Basis of eligibility | ||||||
| Aged (≥65 years) | 6.5% | 20.6% | −42.2 | 6.7% | 7.6% | −3.3 |
| Blind/disabled | 64.6% | 36.0% | 59.5 | 63.9% | 67.6% | −7.9 |
| Adult | 22.0% | 36.0% | −31.3 | 22.5% | 19.0% | 8.7 |
| Other | 6.9% | 7.3% | −1.4 | 6.9% | 5.8.0% | 4.5 |
| Length of followup (months, mean, SD) | 38.8 (20.4) | 33.6 (18.1) | 26.57 | 38.7 (20.3) | 38.0 (20.2) | 3.72 |
| Charlson-Deyo comorbidity index (mean, SD) | 1.16 (1.39) | 0.41 (1.01) | 61.9 | 1.11 (1.33) | 1.26 (1.80) | −9.4 |
| Comorbid conditions | ||||||
| Rheumatoid arthritis and other inflammatory polyarthropathies | 10.6% | 0.7% | 43.6 | 8.7% | 7.6% | 4.1 |
| Autoimmune thyroid disorders | 0.1% | 0.0% | 3.7 | 0.1% | 0.1% | 0.9 |
| Anemia | 14.2% | 3.4% | 39.1 | 13.2% | 13.4% | −0.6 |
| Pericarditis | 0.3% | 0.0% | 6.5 | 0.2% | 0.1% | 1.2 |
| Raynaud's syndrome | 1.2% | 0.0% | 14.9 | 0.7% | 0.4% | 3.2 |
| Thrombocytopenia | 1.8% | 0.2% | 16.6 | 1.6% | 1.4% | 1.7 |
| Myositis | 9.8% | 1.3% | 37.9 | 8.9% | 8.5% | 1.4 |
| Hypertension | 30.2% | 15.9% | 34.5 | 29.2% | 32.1% | −6.5 |
| Renal disease | 7.5% | 1.8% | 27.3 | 6.9% | 6.7% | 0.7 |
| Depression | 15.7% | 8.0% | 23.8 | 15.3% | 16.1% | −2.1 |
| Cardiac disease | 24.3% | 10.8% | 36.2 | 23.3% | 25.3% | −4.6 |
| Cerebrovascular disease | 4.8% | 2.6% | 11.5 | 4.7% | 4.9% | −1.2 |
| Liver disease | 2.1% | 0.8% | 11 | 2.0% | 2.2% | −1.2 |
| Pulmonary disease | 17.5% | 8.3% | 27.6 | 17.0% | 18.9% | −4.8 |
| Nephritis* | 4.7% | 0.5% | 26.7 | 4.1% | 3.5% | 3.4 |
| Concomitant medications of interest** | 3.5% | 2.2% | 7.7 | 3.5% | 3.3% | 0.8 |
†The absolute value of standardized difference <10 is a good match.
*Nephritis was not included in renal disease.
**Concomitant medications include hydralazine, quinidine, procainamide, phenytoin, isoniazid, and d-penicillamine.