Supplementary Material for: Association of Co-Occurring Serious Mental Illness with Emergency Hospitalization in People with Chronic Kidney Disease

Background/Aims: Chronic kidney disease (CKD) and serious mental illness (SMI) are both associated with an increased risk for repeated hospitalization. The objective of this study was to determine if co-occurring SMI exacerbates the risk for subsequent hospitalization, particularly through the emergency department (ED), among people with CKD. Methods: People hospitalized in Washington State from April 2006 to December 2008 were separated into cohorts with diagnoses of CKD (n = 31,166), SMI (defined by schizophrenia and/or mood disorder; n = 20,167) or CKD with co-occurring SMI (n = 717), and a reference cohort without either diagnosis (n = 548,532). Main outcomes were rehospitalization for condition(s) other than mental illness: (1) through the ED; (2) any admission, and (3) admission resulting in death. Cox regression was used to analyze time to main outcomes controlling for prespecified covariates associated with rehospitalization. Results: The risk of rehospitalization via the ED was increased for people with CKD (hazard ratio, HR = 1.24, 95% confidence interval, CI = 1.21-1.28, p Conclusion: In people with CKD, co-occurring SMI increased the risk of experiencing rehospitalization, particularly through the ED. Studies of strategies to address SMI in the CKD population are needed to mitigate the risk of repeat hospital admissions.背景与目的：慢性肾脏病（Chronic kidney disease, CKD）与严重精神疾病（serious mental illness, SMI）均与重复住院风险升高相关。本研究旨在明确慢性肾脏病患者合并严重精神疾病是否会增加后续住院风险，尤其是通过急诊室（emergency department, ED）途径的住院风险。 方法：本研究纳入2006年4月至2008年12月在华盛顿州住院的患者，按诊断分为4个队列：慢性肾脏病组（n=31166）、严重精神疾病组（定义为精神分裂症和/或心境障碍，n=20167）、慢性肾脏病合并严重精神疾病组（n=717），以及无上述任一诊断的参照队列（n=548532）。主要结局指标为非精神疾病相关的再次住院：（1）经急诊室途径的住院；（2）任意类型的住院；（3）导致死亡的住院。采用Cox回归分析主要结局的发生时间，并校正预先设定的与再次住院相关的协变量。 结果：慢性肾脏病患者经急诊室再次住院的风险升高（风险比（hazard ratio, HR）=1.24，95%置信区间（confidence interval, CI）=1.21-1.28，p）。 结论：慢性肾脏病患者合并严重精神疾病会升高再次住院风险，尤其是经急诊室途径的住院风险。未来需开展针对慢性肾脏病群体中严重精神疾病干预策略的研究，以降低重复住院的风险。