A Retrospective, Single-Center Study Analyzing Kidney Functions in Sarcoidosis

Abstract

Objective: Sarcoidosis is a complex chronic disease of unknown etiology that is characterized by non-caseating granulomas. Lung and lymph node involvement is most common; however, various kidney function disorders may occur in these patients. This study aimed to investigate kidney and rarely assessed features in patients with sarcoidosis. Methods: This study evaluated pulmonary sarcoidosis patients aged 18 years and over, who presented to the nephrology outpatient clinic of SBU Tepecik Training and Research Hospital. In addition to the general sarcoidosis parameters, serum 25(OH)D level, tubular functions, and aortic arch calcification were also investigated. Results: Our study included 105 patients, of whom 74 (70.5%) were females and 31 (29.5%) were males. The mean age was 46.78 ± 12.54 years. The history of nephrolithiasis was present in 21 (20%) and aortic calcification was determined in 18 (17.1%) patients. The 25(OH)D level was below 20 ng/mL in 75 (71.4%) patients, and 21 (20%) patients were hypercalcemic. Smoking history was determined in 24 (22.9%) patients, and 25(OH)D levels (cut-off 20 ng/mL) were higher in smokers than non-smokers. Additionally, a rare finding of asymptomatic renal tubular acidosis was detected in 4 (3.8%) patients. The 24-hour urine calcium excretion was >250 mg/day in 27 (25.7%) patients, and 40 (38.1%) patients were hypercalcemic and/or hypercalciuric. Conclusion: Our study revealed a low 25(OH)D level. The incidence of aortic arch calcification as a possible marker of atherosclerosis was also higher than expected and the frequency was higher in patients with higher 25(OH)D levels. As a rarely examined entity in patients with sarcoidosis, renal tubular acidosis type I was detected in 4 patients. Beyond classical kidney findings other features should be analyzed in sarcoidosis.