Supplementary Material for: Effect of frail phenotype on cardiorenal risk and healthcare utilization in older patients with chronic kidney disease

Introduction
Limited data have addressed frailty’s role in cardiorenal risk among older adult patients with chronic kidney disease (CKD). We investigated whether frailty could predict major renal and cardiovascular events, healthcare utilization, and mortality in these patients.
Methods
We conducted a prospective cohort enrolling patients ≥ 75 years with a stable estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2. Frailty phenotype consists of shrinking, low activity, exhaustion, weakness, and slowness, scored 0 to 5. The primary composite renal outcome was a ≥ 25 % decrease in eGFR concurrent with CKD stage progression or dialysis initiation. Secondary outcomes included major adverse cardiovascular events (MACE), emergency room (ER) visits, all-cause mortality, and hospitalization. Using multivariate Cox models with/without competing risk analyses, we explored frailty’s impact on these outcomes.
Results
Among 203 older CKD patients (mean age 81.6 ± 5.0 years, female 40.9 %, diabetes 33.0 %, body mass index 24.9 ± 3.7 kg/m2), 67.9% were frail. Over 3.47 years, 38.9% faced composite renal outcomes, 13.3% MACE, 15.3% mortality, and more than half utilized healthcare. Every one-point frailty elevated composite renal outcome risk by 28.0 % (HR: 1.28, 95% CI:1.03–1.59) and significantly increased secondary outcomes (hospitalization [HR: 1.24, 95% CI: 1.06–1.46], unexpected ER visit [HR: 1.20, [95% CI:1.03–1.39], and mortality [HR: 1.51, 95% CI: 1.06–2.16]) but not for MACE [HR: 1.43, 95% CI: 0.99–2.08]. Results were consistent across subgroups and competing risk analysis.
Conclusion
In CKD patients ≥ 75 years, frailty was associated with progressive kidney disease, increased mortality and healthcare utilization.

引言
目前针对老年慢性肾脏病（CKD）患者衰弱与心肾风险相关性的研究较为有限。本研究旨在探讨衰弱是否可预测此类患者的主要肾脏及心血管事件、医疗资源利用情况与全因死亡率。

方法
本研究为前瞻性队列研究，纳入年龄≥75岁、估算肾小球滤过率（eGFR）稳定且<60 mL/min/1.73 m²的慢性肾脏病患者。衰弱表型包含体重减轻、活动量减少、疲惫感、肌力下降及行动迟缓，评分范围为0~5分。主要复合肾脏结局为eGFR较基线下降≥25%，同时伴随CKD分期进展或启动透析治疗。次要结局包括主要不良心血管事件（MACE）、急诊室（ER）就诊、全因死亡率及住院事件。本研究采用带/不带竞争风险分析的多变量Cox模型，探讨衰弱对上述结局的影响。

结果
本研究共纳入203例老年慢性肾脏病患者，平均年龄为81.6±5.0岁，女性占比40.9%，糖尿病患病率33.0%，体质量指数为24.9±3.7 kg/m²，其中67.9%的患者存在衰弱。随访3.47年期间，38.9%的患者出现复合肾脏结局，13.3%发生主要不良心血管事件，15.3%出现全因死亡，超过半数患者存在医疗资源利用情况。衰弱评分每增加1分，复合肾脏结局发生风险升高28.0%（风险比HR=1.28，95%置信区间CI：1.03~1.59），同时次要结局风险亦显著升高：住院（HR=1.24，95%CI：1.06~1.46）、非计划急诊就诊（HR=1.20，95%CI：1.03~1.39）及全因死亡（HR=1.51，95%CI：1.06~2.16），但主要不良心血管事件风险无显著升高（HR=1.43，95%CI：0.99~2.08）。亚组分析及竞争风险分析结果均保持一致。

结论
对于年龄≥75岁的慢性肾脏病患者，衰弱与肾脏疾病进展、全因死亡率升高及医疗资源使用增加显著相关。