Table 1.
Characteristics of patients at diagnosis stratified by renal function trajectory*
| Characteristic | Overall | Rapid decline | Impaired | Preserved | Recovery | P |
|---|---|---|---|---|---|---|
| No. (%) of cohort | 255 (100) | 20 (8) | 82 (32) | 129 (51) | 24 (9) | – |
| Posterior probability of group membership, median (IQR) | – | 1.0 (1.0–1.0) | 0.99 (0.98–1.0) | 0.99 (0.92–1.0) | 0.99 (0.99–1.0) | – |
| No. of visits (36 months of follow-up), median (IQR) | 9 (5–15) | 7 (4–10) | 10 (7–16) | 8 (6–15) | 8 (4–15) | 0.08 |
| Demographic data | ||||||
| Age at diagnosis, mean ± SD | 61 ± 17 | 62 ± 17 | 64 ± 16 | 59 ± 17 | 63 ± 19 | 0.21 |
| Female | 153 (60) | 11 (55) | 53 (65) | 78 (60) | 11 (46) | 0.40 |
| Race/ethnicity | ||||||
| White | 213 (87) | 18 (95) | 70 (86) | 103 (84) | 22 (92) | |
| Black | 6 (2) | 0 (0) | 3 (4) | 2 (2) | 1 (4) | – |
| Hispanic | 9 (4) | 0 (0) | 2 (2) | 7 (6) | 0 (0) | – |
| Asian | 4 (2) | 1 (5) | 0 (0) | 3 (2) | 0 (0) | – |
| Other | 5 (2) | 0 (0) | 1 (1) | 3 (2) | 1 (4) | – |
| Not recorded | 9 (4) | 0 (0) | 5 (6) | 4 (3) | 0 (0) | – |
| Clinical characteristics at baseline | ||||||
| ANCA type | 0.91 | |||||
| MPO | 182 (71) | 15 (75) | 60 (73) | 91 (71) | 16 (67) | – |
| PR3 | 73 (29) | 5 (25) | 22 (27) | 38 (29) | 8 (33) | – |
| BVAS/GPA, median (IQR) | 4 (4–6) | 5 (4–7) | 4 (4–6) | 4 (3–6) | 6 (4.5–7) | <0.001 |
| Renal† | 175 (69) | 20 (100) | 68 (83) | 63 (49) | 24 (100) | <0.001 |
| Mucosal/ocular† | 24 (9) | 0 (0) | 3 (4) | 20 (16) | 1 (4) | 0.01 |
| Pulmonary† | 106 (42) | 11 (55) | 26 (32) | 63 (49) | 6 (25) | 0.02 |
| Neurologic† | 25 (10) | 2 (10) | 6 (7) | 16 (12) | 1 (4) | 0.49 |
| Biopsy category | ||||||
| No.‡ | 66 | 9 | 31 | 17 | 9 | |
| Crescentic | 16 (24) | 2 (22) | 8 (26) | 3 (18) | 3 (19) | – |
| Focal | 10 (15) | 0 (0) | 7 (23) | 3 (18) | 0 (0) | – |
| Mixed | 14 (21) | 2 (22) | 6 (19) | 3 (18) | 3 (33) | – |
| Sclerotic | 20 (30) | 4 (44) | 8 (26) | 6 (35) | 2 (22) | – |
| Normal or other | 6 (9) | 1 (11) | 2 (7) | 2 (12) | 1 (11) | – |
| Comorbidities | ||||||
| CCI, median (IQR) | 4 (2–6) | 4.5 (3.5–6) | 4 (3–6) | 3 (1–7) | 4 (2.5–5) | 0.01 |
| Baseline diabetes mellitus | 41 (16) | 3 (15) | 17 (21) | 19 (15) | 2 (8) | 0.46 |
| Baseline hypertension§ | 122 (48) | 12 (60) | 43 (52) | 54 (42) | 13 (54) | 0.25 |
| Baseline renal function | ||||||
| Pretreatment eGFR (−365 to −30 days), median (IQR)¶ | 65 (34–81) | 48 (37–88) | 44 (25–72) | 71 (50–81) | 75 (41 −88) | 0.02 |
| Baseline eGFR (±30 days), median (IQR))¶ | 40 (17–80) | 7 (6–9) | 25 (17–36) | 78 (51–92) | 10 (7–16) | <0.001 |
| Induction treatment | ||||||
| CYC-based | 100 (39) | 8 (40) | 34 (41) | 47 (36) | 12 (50) | – |
| RTX-based | 121 (47) | 11 (55) | 40 (49) | 58 (45) | 12 (50) | – |
| Other | 34 (13) | 1 (5) | 8 (10) | 24 (19) | 1 (4) | – |
| Plasma exchange# | 67 (26) | 15 (75) | 25 (30) | 13 (10) | 14 (58) | <0.001 |
| Maintenance treatment | ||||||
| RTX** | 113 (44) | 6 (30) | 39 (48) | 59 (46) | 9 (38) | 0.07 |
| Non-RTX immunosuppression | 116 (45) | 7 (35) | 38 (46) | 62 (48) | 9 (38) | 0.18 |
| None | 33 (13) | 6 (30) | 10 (12) | 15 (12) | 2 (8) | 0.02 |
| Lost to follow-up or deceased before maintenance period | 20 (8) | 3 (15) | 5 (6) | 7 (5) | 5 (21) | 0.02 |
Values are the number (%) unless indicated otherwise. P values shown reflect analysis of variance (for normally distributed continuous variables), Kruskal-Wallis (for other continuous variables), and chi-square or Fisher’s test (for categorical variables) results across the 4 groups. Column sums are >100% in some cases for maintenance treatment because patients could be categorized as receiving both non-rituximab (RTX) maintenance immunosuppression and maintenance RTX. Data in this table are not from the United States Renal Data System. ANCA = antineutrophil cytoplasmic antibody; BVAS = Birmingham Vasculitis Activity Score; CCI = Charlson Comorbidity Index; CYC = cyclophosphamide; eGFR = estimated glomerular filtration rate (ml/minute/1.73 m2); GPA = granulomatosis with polyangiitis; IQR = interquartile range; MPO = myeloperoxidase; PR3 = proteinase 3.
Organ system involvement by BVAS/GPA score.
Total number with biopsy in each group. Columns may add up to smaller numbers due to nonclassifiable or normal biopsies.
Includes n = 3 total patients with comorbid hypertension of unknown onset time.
Relative to the index date (date of treatment initiation); n = 143 for pretreatment eGFR, n = 255 for baseline eGFR.
Plasma exchange was not mutually exclusive with other treatment regimens.
Patients who received short, “bridging” courses of cyclophosphamide with initiation of RTX were categorized as receiving primarily RTX-based induction treatment (n = 67 total, including n = 6 rapid decline, n = 24 impaired, n = 31 stable, and n = 6 recovery.) Maintenance treatment column sums may exceed 100% because patients could be classified as using both RTX and non-RTX maintenance immunosuppression.