Clinicopathological features for the prediction of immunosuppressive treatment responses in sarcoidosis-related kidney involvement: a single-center retrospective study

Astratt

Background/aim: Sarcoidosis is a multisystem disorder that affects many organs, including the kidneys. This single-center retrospective study investigated the clinical, pathological, and laboratory findings of patients with kidney sarcoidosis who were treated with immunosuppressives.Materials and Methods: Twenty-three patients with biopsy-confirmed kidney sarcoidosis were included. Demographics, clinical, pathological, and laboratory findings, in addition to treatments, and outcomes of twenty patients with at least one month of follow-up were evaluated.Results: Median age at the time of biopsy was 47 years(60.9 % female). Median baseline eGFR and proteinuria were 21.5 ml/min and 1 g/g or g/day, respectively. Nineteen of the 23 patients were diagnosed with non-glomerular disease (Four patients had glomerular diseases). Extrarenal sarcoidosis was present in 86.7% of patients. Granulomatous interstitial nephritis(56.5 %) and nephrosclerosis with intratubular calcific casts(17.4 %) were the two most common diagnoses. All patients initially received 1 mg/kg/day steroids for kidney involvement. Although no statistical difference was observed in kidney function during follow-up, steroids improved eGFR in the first month compared with baseline in patients with non-glomerular diseases(p=0.049). Eventually, 45 % of the patients developed end-stage-kidney-disease, and 45 % of cohort had a treatment response. Patients with higher baseline calcium levels(p=0.03) and lower degrees of interstitial fibrosis/tubular atrophy(p=0.043) had better kidney outcomes. Moreover, none of the patients with sarcoidosis-related secondary glomerular disease had a treatment response(p=0.043).Conclusions: Hypercalcemia and lower IF/TA rates might be associated with better outcomes in sarcoidosis-related kidney involvement under immunosuppressives. Also, late diagnosis, irregular follow-up, and glomerular disorders could be poor prognostic factors.