Table 5.
Main characteristics (renal tubular acidosis and GN) of patients with primary SS presenting with renal involvement
| Feature | Patients, n (%) |
|---|---|
| Renal tubular acidosis | |
| Prevalence (n = 2005) | 186 (9) |
| Female:male ratio (n = 208) | 27:1 |
| Age at diagnosis, years (n = 208) | 41 |
| RTA classification (n = 321) | |
| Type I (distal RTA) | 313 (97) |
| Type II (proximal RTA/Fanconi syndrome) | 8 (3) |
| Symptomatic presentation (n = 130) | |
| Hypokalaemic weakness/paralysis | 90 (69) |
| Renal colics | 23 (12) |
| Radiological nephrocalcinosis | 33 (17) |
| Osteomalacia | 26 (13) |
| Polyuria/polydipsia | 7 (4) |
| Renal failure (creatinine >1.3 mg/dl) (n = 198) | 47 (24) |
| Renal biopsy (n = 321) | 149 (46) |
| Histopathological features (n = 149) | |
| Interstitial nephritis | 140 (94) |
| Other features | 9 (6) |
| Immunological profile | |
| Anti-Ro (n = 225) | 160 (71) |
| Anti-La (n = 215) | 116 (54) |
| GN | |
| Prevalence (n = 2005) | 78 (4) |
| Female:male ratio (n = 81) | 19:1 |
| Age at diagnosis, years (n = 81) | 53 |
| Clinical presentation (n = 76) | |
| Oedema/nephrotic syndrome | 23 (22) |
| Laboratory abnormalities | 43 (78) |
| Laboratory abnormalities | |
| Renal failure (creatinine >1.3 mg/dL) (n = 72) | 36 (50) |
| 24 h proteinuria >0.5 g (n = 36) | |
| 0.5–1 g | 4 (11) |
| 1–1.5 g | 7 (19.5) |
| >1.5 g | 25 (69.5) |
| Haematuria (n = 68) | 35 (51) |
| Renal biopsy (n = 321) | 149 (46) |
| Histopathological features (n = 149) | |
| Membranoproliferative GN | 47 (38) |
| Mesangial proliferative GN | 29 (23) |
| Membranous glomerulonephritis | 28 (22) |
| Focal segmental glomerulonephritis | 21 (17) |
| Crescentic rapidly progressive GN | 9 (7) |
| IgA nephropathy | 7 (6) |
| Glomeruloesclerosis | 2 (2) |
| Minimal change nephropathy | 2 (2) |
| Thin basement membrane nephropathy | 1 (1) |
| GN not specified | 3 (2) |
| Immunological profile | |
| Anti-Ro (n = 65) | 47 (72) |
| Anti-La (n = 65) | 29 (45) |
| Cryoglobulins (n = 56) | 29 (52) |
| ANCA (n = 16) | 8 (50) |
Variables were not detailed in all studies and the prevalence of a specific feature is stated as the number of cases with that feature/number of cases in which the feature was detailed. RTA: renal tubular acidosis.