Comprehensive analysis of clinical and laboratory features of 440 published cases of Sjogren's syndrome and renal tubular acidosis

Aim To describe the clinical and laboratory features of Sjogren's syndrome (SS) with renal tubular acidosis (RTA) from published literature. Methods A systematic search of indexed publications in all languages till December 2021 identified cases of SS with RTA (SS-RTA) and were included if either antibody (anti-SSA/anti-SSB) or salivary gland histopathology were positive. Results There were 440 cases of SS-RTA (63.9% from Asia, 95.5% women). The median (range) age was 37 (6-78) years. Only 7.7% had a previous diagnosis of SS. Oral or ocular sicca symptoms were present in 63.7%. Positive ocular tests, oral tests, anti-SSA, anti-SSB and salivary gland histopathology were reported in 256/331 (77.3%), 123/128 (96%), 382/407 (93.9%), 298/379 (78.6%), and 246/268 (91.8%), respectively. Hypokalemic paralysis (HP) was the presenting feature in 63.6%; 25% had multiple episodes of HP and 8.4% had respiratory paralysis. Type 1, type 2, combined type 1 & 2, and type 4 RTA was seen in 388, 8, 38, and 3 patients, respectively. Proximal dysfunction and RTA complications were infrequently evaluated. Fanconi syndrome, nephrogenic diabetes insipidus, proteinuria, and low estimated glomerular filtration rate were found in 45, 21, 178, and 157, respectively. Nephrocalcinosis, renal stones, and osteomalacia were reported in 92, 79, and 72, respectively. Tubulointerstitial nephritis was found in 142 out of 152 renal biopsies. Conclusion SS-RTA is an early manifestation of SS characterized by younger age and subclinical sicca symptoms. Although evaluated less frequently, oral sicca signs and salivary gland biopsy have a high positive yield. HP is the most common presentation. RTA is mostly distal; proximal dysfunction and complications were infrequently assessed.

Automated summary

Sjogren's syndrome with renal tubular acidosis (SS-RTA) is an early manifestation of Sjogren's syndrome characterized by younger age and subclinical sicca symptoms. Ocular and oral tests, as well as salivary gland histopathology, have a high positive yield. Hypokalemic paralysis is the most common presenting feature. RTA is mostly distal, and proximal dysfunction and complications are infrequently assessed.