Table 2

Variables at baseline, pre-PSM and post-PSM for patients with ≥1 year of follow-up

VariableBias pre-PSMBias post-PSM
Belimumab (n=259)SoC (n=706)Bias (%)*Belimumab (n=179)SoC (n=179)Bias (%)*
Mean age, years42.636.946.040.440.7−2.4
Mean age squared, years1937.41541.037.61763.41792.3−3.0
Female, %93.488.816.391.691.60.0
Black, %21.614.618.322.323.5−2.7
Asian†/other race, %9.328.0−49.612.812.80.0
Mean SLE duration, years7.−3.2
Smoker, %3.924.2−−4.6
Hypertension‡, %53.338.031.145.845.80.0
Dyslipidaemia, %22.834.7−26.525.122.95.2
Proteinuria, %13.533.0−47.416.817.9−2.9
Number of ACR classification criteria satisfied6.05.722.
Baseline SLEDAI7.910.0−−3.7
Corticosteroid use, %64.962.−2.4
Antimalarial use, %71.856.432.665.967.0−2.4
Immunosuppressive use, %55.234.442.745.846.4−1.1
SDI score=1, %27.814.233.924.625.7−2.6
SDI score ≥2, %27.810.246.016.816.80.0
  • *The extent of balance in clinical characteristics between groups was assessed using a standardised distance (bias) for each of the variables in the PS model. The standardised distance in the PS-matched sample across groups for all variables used to determine PS values ideally should be <5%; however, a standardised distance of <10% for all variables is considered adequate balance.

  • †Asian from the BLISS LTE population refers to patients with Central Asian, East Asian, Japanese, South Asian and Southeast Asian heritage; and Asian from the TLC refers to patients of Chinese heritage.

  • ‡Patients who met any of the following criteria at baseline were defined as having hypertension: (1) systolic blood pressure ≥140 mm Hg or (2) diastolic pressure ≥90 mm Hg or (3) use of antihypertensive medications. The BLISS database had a flag for patients with baseline hypertension, but any BLISS patients who were not flagged were defined as having hypertension based on the same criteria used for TLC patients.

  • ACR, American College of Rheumatology; PS, propensity score; PSM, propensity score matching; SDI, Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index; SLE, systemic lupus erythematosus; SLEDAI, SLE Disease Activity Index; SoC, standard of care; TLC, Toronto Lupus Cohort.