Table 1

Patient characteristics at the time of biopsy overall and stratified by C9 staining groups

Overall sample
n=30
Tubular C9 positive
(stain intensity 1–3)
n=7
Tubular C9 negative
(stain intensity 0)
n=23
P value
Demographics/clinical parameters
Age, years35 (23–41)36 (31–56)27 (21–39)0.20
Female sex, n (%)24 (80%)5 (71%)19 (83%)0.60
Black, n (%)9 (30%)9 (30%)21 (70%)0.30
Hispanic, n (%)11 (37%)4 (57%)7 (30%)0.37
Hydroxychloroquine, n (%)24 (80%)4 (57%)20 (87%)0.12
Prednisone, n (%)19 (63%)2 (29%)17 (74%)0.07
Immunotherapy*, n (%)16 (53%)4 (57%)12 (52%)>0.99
SLEDAI-2K†11 (8–12)12 (10–12)10 (6–12)0.83
Systolic BP, mm Hg120 (112–133)133 (113–150)120 (110–130)0.18
Diastolic BP, mm Hg75 (67–86)80 (70–100)70 (65–84)0.24
Laboratory parameters
eGFR, mL/min/1.73 m2111.2 (74.7–132.0)57.9 (16.1–139.6)118.2 (95.2–132.0)0.17
Creatinine, mg/dL0.7 (0.6–0.9)1.6 (0.5–3)0.7 (0.6–0.8)0.23
Proteinuria‡, g/24 hours2.9 (1.7–5.6)6.2 (3.3–13.1)2.4 (1.3–4.6)0.001
Nephrotic range proteinuria§, n (%)11 (37%)5 (71%)6 (26%)0.07
Albumin, mean±SD, g/dL3.0±0.72.5±0.63.1±0.70.05
Hematuria¶, n (%)12 (40%)4 (57%)8 (35%)0.39
Pyuria¶**, n (%)13 (43%)2 (29%)11 (48%)0.43
Serum C3 <70 mg/dL, n (%)20 (67%)4 (57%)16 (70%)0.66
Serum C4 <14 mg/dL, n (%)20 (67%)3 (43%)17 (74%)0.18
dsDNA ≤75 IU/mL, n (%)13 (43%)3 (43%)10 (44%)>0.99
  • All continuous variables presented as median (IQR) except for albumin.

  • *Mycophenolate mofetil, cyclophosphamide, tacrolimus, azathioprine, rituximab or belimumab.

  • †SLEDAI-2K= Systemic Lupus Erythematosus. Disease Activity Index 2000.

  • ‡24-hour urine protein collection and, if not available, spot urine protein to creatinine ratio.

  • §Proteinuria>3.5 g/24 hours.

  • ¶Presence of 5 or more red blood cells per high-power field.

  • **Presence of 5 or more white blood cells per high-power field.

  • BP, blood pressure; eGFR, estimated glomerular filtration rate.