Table 2.
Patient demographics and key laboratory findings at the time of the diagnostic kidney biopsy and the follow-up data. The data are presented separately for all patients, TIN, TINU and TINU with chronic uveitis
| All patients n = 52 |
TIN n = 19 |
TINU n = 33 |
p valuef | TINU with chronic uveitis n = 21 |
p value† | |
|---|---|---|---|---|---|---|
| Age at diagnosis, years | 13.1 (1.8-16.9) | 11.8 (1.8–15.4) | 13.8 (5.6–16.9) | 0.38 | 13.9 (5.6–16.9) | 0.28 |
| Median follow-up time, years | 5.7 (1.1–21.2) | 5.6 (1.1–15.5) | 4.5 (1.2–21.2) | 0.54 | 6.1 (1.9–21.2) | 0.06 |
| Age at the latest follow-up, years | 18.4 (4.5–31.5) | 16.7 (7.7–28.8) | 17.9 (4.5–31.5) | 0.21 | 18.5 (11.3–31.5) | 0.03 |
| Initial data | ||||||
| CRP, mg/l (n = 41) | 50 (3–224) | 50 (3–224)* | 43 (3–135)# | 0.80 | 33 (3–110)# | 0.77 |
| ESR, mm/h | 94 (9–140) | 102 (64–128)* | 86 (9–128) | 0.68 | 79 (14–128) | 0.07 |
| P-Cr, μmol/l | 162 (47–1016) | 234 (64–1016) | 139 (47–416) | 0.01 | 169 (47–416) | 0.24 |
| P-Urea, mmol/l (n = 49) | 9.0 (4.4–32.7) | 10.8 (5.5–32.7) | 7.9 (4.4–18.3) | 0.04 | 8.5 (4.7–16.8) | 0.28 |
| U-αl-MG mg/l (n = 14) | 80 (11–246) | 141 (75–246) | 78 (11–137) | 0.40 | 76 (11–137) | 0.52 |
| U-β2-MG μg/l (n = 36) | 24250 (1600–120000) | 23438 (2090–12000) | 24800 (1600–110200) | 0.64 | 34000 (1600–110200) | 0.33 |
| Haemoglobin, g/L | 103 (85–129) | 99 (85–126) | 104 (86–129) | 0.14 | 104 (94–129) | 0.30 |
| WBC, E9/L (n = 39) | 8.9 (4.3–31.0) | 8.4 (5.9–31.0) | 8.9 (4.3–12.9) | 0.76 | 8.8 (4.3–12.9) | 0.63 |
| B-Eosinophiles, E9/l (n = 39) | 0.31 (0–0.96) | 0.31 (0–0.71) | 0.31 (0–0.96) | 0.90 | 0.35 (0–0.84) | 0.67 |
| P-Pi, mmol/l (n = 33) | 1.09 (0.68–2.27) | 0.98 (0.78–2.27) | 1.11 (0.68–1.46) | 0.35 | 1.09 (0.68–1.46) | 0.80 |
| Follow-up data | ||||||
| P-Cr, μmol/l | 72 (37–112) | 64 (37–111) | 74 (50–112) | 0.52 | 76 (50–112) | 0.28 |
| eGFR, ml/min/1.73 m2 | 106 (61–183) | 117 (61–183) | 106 (68–158) | 0.64 | 109 (68–158) | 0.68 |
| eGFR < 90 ml/min/1.73 m2, n (%) | 13 (25) | 5 (28) | 8 (24) | 0.78 | 5 (24) | 0.82 |
| CKD 5*, n (%) | 1 (2) | 1 (6) | 0 | - | 0 | - |
| Elevated blood pressure, n (%) | 7 (13) | 2 (11) | 5 (15) | 0.69 | 3 (14) | 0.92 |
| LMWP n (%) | 6 (12) | 6 (33) | 0 (0) | - | 0 (0) | - |
| Nephritic relapse | 12 (23) | 5 (26) | 7 (21) | 0.67 | 6 (29) | 0.44 |
TIN, tubulointerstitial nephritis; TINU, tubulointerstitial nephritis with uveitis syndrome; chronic uveitis was defined as uveitis lasting more than 3 months despite treatment and/or with relapse within 3 months after discontinuing treatment. CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; P-Cr, plasma creatinine concentration; eGFR, estimated glomerular filtration rate; U-α1-MG, urine alpha-1-microglobulin concentration (normal value < 15 mg/l); U-β2-MG, urine beta-2-microglobulin concentration (normal value < 250 μg/l); WBC, white blood cells; P-Pi, plasma phosphate concentration; CKD 5, stage 5 chronic kidney disease; reported values are median values with range in brackets. For continuous variables, the non-parametric Mann–Whitney U test was used. A two-tailed p value is reported
*TIN n = 13 for CRP and n = 17 for ESR
#TINU n = 28 and n = 19 in TINU with chronic uveitis group
f Median values were compared between TIN and TINU patients
†Median values were compared between patients with chronic uveitis and all other patients (TIN and TINU without chronic uveitis)