Table 1: Demographic and clinical characteristics of SLE and non-SLE patients.

Before matchingPostmatching
SLE patientsNon-SLE patientsStandardized differenceSLE patientsNon-SLE patientsStandardized difference

N 14,777341,18214,26214,262
Female92.8%66.9%68.292.6%92.4%0.6
Mean age (SD)45.4 (14.3) 48.3 (20.4) −16.645.4 (14.4) 48.0 (14.9) −17.5
Insurance plan type: fee for service70.6%69.7%270.5%72.3%−3.9
Medicare dual eligibility39.7%39.8%−0.239.6%43.2%−7.4
Race
 White39.1%41.1%−4.239.4%40.6%−2.4
 Black36.6%21.0% 35 36.1%34.6% 3.2
 Hispanic11.4%21.6%−27.811.5%10.7% 2.7
 Other/missing13.0%16.3%−9.413.0%14.2%−3.5
Basis of eligibility
 Aged (≥65 years)6.5%20.6%−42.26.7%7.6%−3.3
 Blind/disabled64.6%36.0% 59.5 63.9%67.6%−7.9
 Adult22.0%36.0%−31.322.5%19.0% 8.7
 Other6.9%7.3%−1.46.9%5.8.0% 4.5
Length of followup (months, mean, SD)38.8 (20.4)33.6 (18.1)26.5738.7 (20.3)38.0 (20.2)3.72
Charlson-Deyo comorbidity index (mean, SD)1.16 (1.39)0.41 (1.01)61.91.11 (1.33)1.26 (1.80)−9.4
Comorbid conditions
 Rheumatoid arthritis and other  inflammatory polyarthropathies10.6%0.7%43.68.7%7.6%4.1
 Autoimmune thyroid disorders0.1%0.0%3.70.1%0.1%0.9
 Anemia14.2%3.4%39.113.2%13.4%−0.6
 Pericarditis0.3%0.0%6.50.2%0.1%1.2
 Raynaud’s syndrome1.2%0.0%14.90.7%0.4%3.2
 Thrombocytopenia1.8%0.2%16.61.6%1.4%1.7
 Myositis9.8%1.3%37.98.9%8.5%1.4
 Hypertension30.2%15.9%34.529.2%32.1%−6.5
 Renal disease 7.5%1.8%27.36.9%6.7% 0.7
 Depression15.7%8.0%23.815.3%16.1%−2.1
 Cardiac disease24.3%10.8%36.223.3%25.3%−4.6
 Cerebrovascular disease4.8%2.6%11.54.7%4.9%−1.2
 Liver disease2.1%0.8%112.0%2.2%−1.2
 Pulmonary disease17.5%8.3%27.617.0%18.9%−4.8
 Nephritis*4.7%0.5%26.74.1%3.5%3.4
Concomitant medications of interest**3.5%2.2%7.73.5%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.