Tangri Navdeep, Ferguson Thomas W, Reaven Nancy L, Lai Julie, Funk Susan E, Mathur Vandana
University of Manitoba, Department of Internal Medicine, Max Rady College of Medicine, Winnipeg, Manitoba, Canada.
Seven Oaks Hospital Chronic Disease Innovation Center, Winnipeg, Manitoba, Canada.
Kidney Int Rep. 2023 Feb 1;8(4):796-804. doi: 10.1016/j.ekir.2023.01.029. eCollection 2023 Apr.
Low serum bicarbonate at a single point in time is associated with accelerated kidney decline in patients with chronic kidney disease (CKD). We modeled how changes in serum bicarbonate over time affect incidence of adverse kidney outcomes.
We analyzed data from Optum's deidentified Integrated Claims-Clinical data set of US patients (2007-2019) with ≥1 year of prior medical record data, CKD stages G3 to G5, and metabolic acidosis (i.e., index serum bicarbonate 12 to <22 mmol/l). The primary predictor of interest was the change in serum bicarbonate, evaluated at each postindex outpatient serum bicarbonate test as a time-dependent continuous variable. The primary outcome was a composite of either a ≥40% decline in estimated glomerular filtration rate (eGFR) from index or evidence of dialysis or transplantation, evaluated using Cox proportional hazards models.
A total of 24,384 patients were included in the cohort with median follow-up of 3.7 years. A within-patient increase in serum bicarbonate over time was associated with a lower risk of the composite kidney outcome. The unadjusted hazard ratio (HR) per 1-mmol/l increase in serum bicarbonate was 0.911 (95% confidence interval [CI]: 0.905-0.917; < 0.001). After adjustment for baseline eGFR and serum bicarbonate, the time-adjusted effect of baseline eGFR and other covariates, the HR per 1-mmol/l increase in serum bicarbonate was largely unchanged (0.916 [95% CI: 0.910-0.922; < 0.001]).
In a real-world population of US patients with CKD and metabolic acidosis, a within-patient increase in serum bicarbonate over time independent of changes in eGFR, was associated with a lower risk of CKD progression.
慢性肾脏病（CKD）患者在某一时刻血清碳酸氢盐水平较低与肾脏功能加速衰退相关。我们建立模型来研究血清碳酸氢盐随时间的变化如何影响不良肾脏结局的发生率。
我们分析了Optum公司提供的美国患者（2007 - 2019年）去识别化的综合索赔 - 临床数据集，这些患者有≥1年的既往病历数据，处于CKD G3至G5期且伴有代谢性酸中毒（即初始血清碳酸氢盐水平为12至<22 mmol/L）。感兴趣的主要预测因素是血清碳酸氢盐的变化，在每次索引后门诊血清碳酸氢盐检测时将其评估为一个随时间变化的连续变量。主要结局是估计肾小球滤过率（eGFR）较索引值下降≥40%或有透析或移植证据的复合结局，使用Cox比例风险模型进行评估。
该队列共纳入24384例患者，中位随访时间为3.7年。患者血清碳酸氢盐随时间增加与复合肾脏结局风险降低相关。血清碳酸氢盐每增加1 mmol/L，未调整的风险比（HR）为0.911（95%置信区间[CI]：0.905 - 0.917；P < 0.001）。在调整了基线eGFR和血清碳酸氢盐、基线eGFR的时间调整效应以及其他协变量后，血清碳酸氢盐每增加1 mmol/L的HR基本不变（0.916 [95% CI：0.910 - 0.922；P < 0.001]）。
在美国患有CKD和代谢性酸中毒的真实人群中，患者血清碳酸氢盐随时间增加且独立于eGFR变化，与CKD进展风险降低相关。
