Supplementary Material for: Oxidative Balance Score and Chronic Kidney Disease

Background: The oxidative balance score (OBS) is a composite estimate of the overall pro- and antioxidant exposure status in an individual. The aim of this study was to determine the association between OBS and renal disease. Methods: Using the Reasons for Geographic and Racial Differences in Stroke cohort study, OBS was calculated by combining 13 a priori-defined pro- and antioxidant factors by using baseline dietary and lifestyle assessment. OBS was divided into quartiles (Q1-Q4) with the lowest quartile, Q1 (predominance of pro-oxidants), as the reference. Multivariable logistic regression and Cox proportional hazards models were used to estimate adjusted ORs for albuminuria defined as urine albumin/creatinine ratio (ACR) >30 mg/g, macroalbuminuria defined as ACR >300 mg/g and chronic kidney disease (CKD) defined as estimated glomerular filtration rate 2 according to the Chronic Kidney Disease Epidemiology Collaboration and hazards ratios for end-stage renal disease (ESRD), respectively. Results: Of the 19,461 participants analyzed, 12.9% had albuminuria and 10.1% had CKD at baseline; over a median follow-up of 3.5 years (range 2.14-4.32 years), 0.46% developed ESRD. Higher OBS quartiles were associated with lower prevalence of CKD (OR vs. Q1: Q2 = 0.93 [95% CI 0.80-1.08]; Q3 = 0.90 [95% CI 0.77-1.04] and Q4 = 0.79 [95% CI 0.67-0.92], p for trend Conclusions: These findings suggest that higher OBS is associated with lower prevalence of CKD. Lack of association with ESRD incidence in the multivariable analyses indicates that temporal relation between OBS and renal damage remains unclear.背景：氧化平衡评分（Oxidative Balance Score, OBS）是综合评估个体整体促氧化与抗氧化暴露状态的复合指标。本研究旨在明确OBS与肾脏疾病之间的关联。方法：本研究依托卒中地理与种族差异原因队列研究（Reasons for Geographic and Racial Differences in Stroke cohort study），通过结合13项预先定义的促氧化与抗氧化因素，结合基线膳食与生活方式评估计算OBS。将OBS划分为四分位数组（Q1~Q4），以最低四分位数组Q1（以促氧化因素占主导）作为参照组。分别采用多变量logistic回归模型与Cox比例风险模型，估算尿白蛋白/肌酐比值（urine albumin/creatinine ratio, ACR）>30mg/g定义的白蛋白尿、ACR>300mg/g定义的大量白蛋白尿，以及依据慢性肾脏病流行病学合作组（Chronic Kidney Disease Epidemiology Collaboration, CKD-EPI）公式估算的肾小球滤过率<60mL/min/1.73m²定义的慢性肾脏病（CKD），并分别估算终末期肾病（End-stage renal disease, ESRD）的风险比。结果：在纳入分析的19461名受试者中，基线时12.9%存在白蛋白尿，10.1%患有慢性肾脏病；中位随访时长3.5年（范围2.14~4.32年）后，0.46%的受试者进展为终末期肾病。较高的OBS四分位数组与更低的慢性肾脏病患病率呈负相关（与Q1组相比：Q2组的校正OR值为0.93[95%CI 0.80~1.08；Q3组为0.90[95%CI 0.77~1.04；Q4组为0.79[95%CI 0.67~0.92]，趋势检验p值。结论：本研究结果表明，更高的OBS与更低的慢性肾脏病患病率相关。多变量分析中未观察到OBS与终末期肾病发病的关联，提示OBS与肾损伤之间的时间关联仍不明确。