Table 1.
Baseline demographic, clinical, and laboratory characteristics stratified by complement activation index (CAI).
| Variable | Total (N = 157) | Low CAI (Score 0–1) (n=88) |
High CAI (Score 2–3) (n=69) |
P |
|---|---|---|---|---|
| Demographics | ||||
| Age, years | 40 ± 14 | 41 ± 14 | 40 ± 14 | 0.486 |
| Female, n (%) | 96 (61.1) | 54 (61.4) | 42 (60.9) | 1.000 |
| BMI, kg/m² | 24.4 ± 3.7 | 24.2 ± 3.7 | 24.7 ± 3.7 | 0.374 |
| MAP, mmHg | 98 ± 12 | 97 ± 12 | 100 ± 11 | 0.112 |
| Co-morbidities | ||||
| Hypertension, n (%) | 65 (41.4) | 31 (35.2) | 34 (49.3) | 0.083 |
| Diabetes mellitus, n (%) | 6 (3.8) | 5 (5.7) | 1 (1.5) | 0.229 |
| Laboratory data | ||||
| UPRO, g/24h | 2.7 (1.7-5.2) | 2.3 (1.4–3.5) | 4.6 (2.2–7.5) | <0.001 |
| Urinary C3, mg/L | 3.0 (2.0-10.0) | 2.0 (2.0-3.1) | 7.4 (3.6-25.4) | <0.001 |
| Hemoglobin, g/L | 115 ± 22 | 116 ± 19 | 113 ± 26 | 0.154 |
| Platelets, ×109/L | 253 ± 86 | 264 ± 91 | 238 ± 78 | 0.073 |
| Albumin, g/L | 35.3 ± 6.0 | 37.2 ± 5.0 | 32.8 ± 6.3 | <0.001 |
| Globulin, g/L | 22.0 ± 4.4 | 22.8 ± 3.9 | 21.1 ± 4.8 | 0.010 |
| Serum creatinine, mg/dL | 1.4 (0.9-2.2) | 1.2 (0.9-1.8) | 1.8 (1.2-2.8) | <0.001 |
| eGFR, mL/min/1.73m² | 55 (29-81) | 65(38-92) | 39 (26-64) | <0.001 |
| Urea nitrogen, mg/dL | 25.1 ± 13.6 | 21.9 ± 11.5 | 29.0 ± 15.1 | 0.001 |
| Total cholesterol, mmol/L | 5.7 ± 1.7 | 5.3 ± 1.5 | 6.2 ± 1.8 | 0.003 |
| Triglycerides, mmol/L | 1.6 (1.2-2.6) | 1.4 (1.1-2.1) | 2.0 (1.5-2.8) | 0.003 |
| HDL-C, mmol/L‡ | 1.2 ± 0.4 | 1.1 ± 0.4 | 1.3 ± 0.5 | 0.078 |
| LDL-C, mmol/L‡ | 3.2 ± 1.3 | 3.0 ± 1.2 | 3.5 ± 1.4 | 0.036 |
| LDH, U/L† | 207 ± 65 | 191 ± 41 | 228 ± 82 | 0.008 |
| Cystatin C, mg/L† | 1.6 ± 0.8 | 1.3 ± 0.6 | 1.9 ± 0.8 | <0.001 |
| IgG, g/L§ | 9.3 ± 3.6 | 10.1 ± 3.1 | 8.2 ± 3.8 | <0.001 |
| IgE, IU/mL§ | 45 (22-105) | 51 (20-111) | 43 (25-90) | 0.995 |
| IgA, g/L§ | 3.0 ± 1.1 | 2.9 ± 1.1 | 3.0 ± 1.2 | 0.925 |
| IgM, g/L§ | 1.1 ± 0.5 | 1.1 ± 0.6 | 1.0 ± 0.5 | 0.149 |
| Complement C3, g/L | 1.00 ± 0.22 | 1.04 ± 0.18 | 0.94 ± 0.24 | 0.001 |
| Complement C4, g/L | 0.27 ± 0.09 | 0.27 ± 0.09 | 0.26 ± 0.09 | 0.489 |
| CD4+ T cells,/μL‖ | 780 ± 377 | 809 ± 383 | 745 ± 369 | 0.394 |
| CD8+ T cells,/μL‖ | 433 ± 215 | 443 ± 215 | 421 ± 215 | 0.487 |
| CD20+ cells,/μL¶ | 238 ± 141 | 262 ± 152 | 211 ± 125 | 0.046 |
Data are presented as mean ± SD (median, Q1–Q3) for continuous variables and n (%) for categorical variables.
P-values: continuous variables were compared with the Mann-Whitney U test; categorical variables with the chi-square test or Fisher’s exact test as appropriate.
‡ HDL-C and LDL-C data were available in 144 total patients (Low CAI: 83; High CAI: 61).
† LDH and Cystatin C were available in 139 and 140 total patients, respectively (Low CAI: 78/79; High CAI: 61/61).
§ Immunoglobulins available in 148–152 total patients (Low CAI: 81–84; High CAI: 67–68).
‖ CD4/CD8 available in 135 total patients (Low CAI: 73; High CAI: 62).
¶ CD20 available in 130 total patients (Low CAI: 69; High CAI: 61). BMI, body mass index; MAP, mean arterial pressure; UPRO, 24-hour urine protein; eGFR, estimated glomerular filtration rate; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; LDH, lactate dehydrogenase.
Nominal P values are shown. FDR-adjusted Q values for all baseline comparisons are provided in Supplementary Table 3. Associations with nominal P < 0.05 but Q ≥ 0.05 should be interpreted as exploratory.
Continuous variables are reported with a level of precision consistent with routine laboratory reporting and clinical interpretability. P values ≥0.001 are reported to three decimal places, and P values <0.001 are reported as P < 0.001.