Gender and chronic kidney disease in ankylosing spondylitis: a single-center retrospectively study

Background: Ankylosing spondylitis (AS) is a well-known male-predominant inflammatory disease. This study aimed to assess the gender disparity in chronic kidney disease (CKD) in AS patients in China. Methods: AS patients were retrospectively studied at Peking Union Medical College hospital between January 2002 and June 2018. Results: Among 616 patients with AS, 154 (25.0%) patients had CKD (age, 41.8 +/- 14.2 years; male:female, 3.2:1). Overall, 80 (13.0%) patients had only microscopic hematuria, 62 (10.1%) had proteinuria with or without hematuria, and 33 (5.4%) exhibited a reduced estimated glomerular filtration rate (eGFR, <= 60 mL/min/1.73 m(2)). Male CKD patients had more frequent proteinuria (p < 0.01), less microscopic hematuria only (p < 0.01), and lower eGFR (p = 0.04) compared with females. CKD was independently associated with hyperuricemia and total cholesterol in females, and with hyperuricemia, hypertension, and serum albumin in males. After follow-up for 1-7 years, five patients required renal replacement therapy including two patients who were already at stage 5 CKD when enrolled and three patients whose creatinine doubled. One patient died in the male group. No patients in the female group showed progression of renal dysfunction. Conclusions: CKD is a common comorbidity in patients with AS. Male patients are more likely to develop severe manifestations compared with female patients. Hyperuricemia was a strong independent risk factor for CKD in both genders, while hypertension and low serum albumin were risk factors for CKD only in males.