Supplementary Material for: Association of US Dialysis Facility Staffing with Profiling of Hospital-Wide 30-Day Unplanned Readmission

Background: Unplanned hospital readmissions are a major source of morbidity among dialysis patients, in whom the risk of hospital readmission is exceptionally high. The contribution of dialysis facility staffing to hospital readmission has been largely overlooked. Methods: Using annual data of dialysis patients from the United States Renal Data System from 2010 to 2013, we assessed dialysis facilities with a significantly worse (SW) and facilities with a nonsignificant (NS) standardized readmission ratio (SRR). SRR estimates were risk adjusted for patient factors, past year comorbidities, and index hospitalization characteristics. Facility staffing variables were compared between 2 exposure groups: facilities with SW and NS SRRs. Four measures of staffing, including patient-to-staffing ratio, were compared between SW and matched NS facilities. Results: About 136,000–148,000 dialysis patients with 269,000–319,000 index hospital discharges were used to identify facilities with SW and facilities with NS SRR annually. Approximately 3–4% of facilities were identified as having SW SRR among > 5,000 facilities annually. The percent of nurses-to-total staff was significantly lower in 2010 for SW facilities than in matched NS facilities (42.5 vs. 45.6%, p = 0.012), but this disparity was attenuated by 2013 (44.8 vs. 44.7%, p = 0.949). There was a higher patient-to-nurse ratio for SW facilities than for NS facilities (mean 16.4 vs. 15.2, p = 0.038) in 2010 as well, and the disparity was reduced by 2013. The trends were similar for patient-to-total staff and patient-to-registered nurse, but not statistically significant. Conclusions: This study found that dialysis facilities with SW 30-day readmission rates had lower proportions of nurses-to-total staff and higher patient-to-nurse ratios, but this disparity improved in recent years. Additional research is warranted focusing on how evidence-based staffing at dialysis facilities can contribute to reduction of hospital readmission, and this knowledge is needed to inform clinical practice guidelines and policy decisions regarding optimal dialysis patient staffing.

背景：非计划性住院再入院是透析患者发病的重要诱因之一，该人群的住院再入院风险本就居高不下，但透析机构人员配置对再入院风险的影响长期以来被大幅忽视。方法：本研究使用2010至2013年美国肾脏数据系统（United States Renal Data System）收录的透析患者年度数据，对标准化再入院率（standardized readmission ratio, SRR）显著较差（significantly worse, SW）的透析机构，以及SRR无显著差异（nonsignificant, NS）的透析机构进行评估。SRR的估算值已针对患者个体因素、既往一年合并症情况及初始住院特征完成风险校正。本研究对两组暴露人群——即SW组与NS组透析机构——的人员配置变量进行了对比，最终选取4项人员配置指标（含患者与医护人员配比）在SW组及匹配后的NS组机构间展开比较。结果：本研究每年纳入约13.6万至14.8万名透析患者，对应26.9万至31.9万次初始住院出院病例，用于识别SW组与NS组透析机构。在每年超过5000家透析机构中，约3%至4%的机构被归类为SW组。2010年时，SW组机构的护士占总员工比例显著低于匹配后的NS组机构（42.5% vs 45.6%，p=0.012），但该差异在2013年已趋于消失（44.8% vs 44.7%，p=0.949）。2010年SW组机构的患者与护士配比同样高于NS组机构（均值16.4 vs 15.2，p=0.038），该差异在2013年有所缩小。患者与总员工配比、患者与注册护士配比的变化趋势与之类似，但未达到统计学显著性水平。结论：本研究发现，30天再入院率显著较差的透析机构，其护士占总员工比例更低、患者与护士配比更高，但该差异在近年已有所改善。未来需开展更多研究，聚焦透析机构基于循证医学的人员配置如何助力降低住院再入院风险，该研究结论也可为优化透析患者人员配置的临床实践指南及政策制定提供参考依据。