Comorbidity, Costs and Outcomes in Dialysis Patients

随着透析患者的平均年龄增加到60岁，糖尿病等并存疾病的患病率增加，并发症的增加可能会对透析人群的发病率、死亡率和费用产生深远的影响。一种量化共病的有效工具可能有助于识别资源利用成本高昂的高危患者，帮助制定公共卫生战略，并针对这一高危群体确定最佳的透析治疗干预措施。要在透析人群中有效，共病工具应该是简单、容易验证的，包括某些影响透析患者结局的特定因素，如终末期肾病的持续时间，并包括客观的、可量化的疾病严重程度测量。目前使用的指数，如查尔森合并症指数和并存疾病指数，都不符合所有这些标准。因此，这项研究的具体目的是在大样本透析人群中开发和验证一种简单、专用于透析患者并考虑疾病严重程度的共病指数。既往研究表明，共病发生率高的患者腹膜透析技术失败率较高。这项研究还将检查腹膜透析技术失败后观察到的死亡率增加是由于这些患者的高并存率还是技术失败本身导致了更高的死亡率。这项研究将使用美国肾脏数据系统(USRDS)透析发病率和死亡率研究(DMMS)中的现有数据。共病工具将从DMMS III研究中6300名流行患者的子集中开发出来。根据Cox比例危险度，将确定每种并存情况下死亡的相对风险，并根据相对风险给出分数。该评分系统将在以下人群中得到验证：在DMMS-IV研究中，以联邦医疗保险为主要或唯一支付者的普遍血液透析患者，在DMMS-IV研究中，非联邦医疗保险为主要或唯一支付者的普遍血液透析患者，在DMMS第二波研究中，1996年或1997年开始透析的血液和腹膜透析事件，无论保险状况如何。感兴趣的结果将是住院天数和医疗保险住院成本(通过ANOVA)和死亡(通过COX比例风险)。DMMS II的进一步数据将被用来检查发生腹膜透析患者的死亡风险，这些患者在发生血液透析的患者中未能通过该技术。由于共病预测腹膜透析技术的失败，上述分析将有助于在透析开始时根据共病确定最佳的透析方式。

As the mean age of incident dialysis patients has increased to 60 years and prevalence of comorbid conditions such as diabetes has increased, increasing comorbidity may profoundly impact on morbidity, mortality and costs in the dialysis population. A valid tool that quantifies comorbidity may help to identify high-risk patients with expensive resource utilization, help to flame public health strategies and define optimal dialysis therapeutic interventions targeted towards this high-risk group. To be valid in the dialysis population, the comorbidity tool should be simple, readily verifiable, include certain specific factors that influence outcomes in dialysis patients such as duration of end-stage renal disease and include objective, quantifiable measures of disease severity. None of the currently used indices such as the Charlson Comorbidity Index and the Index of Coexistent Diseases meet all of these criteria. Therefore, the specific aims of this study are to develop and validate in a large sample of dialysis population an index of comorbidity that is simple, specific for dialysis patients and accounts for disease severity. Prior studies showed patients with high comorbidity have higher peritoneal dialysis technique failure. This study will also examine whether the increased mortality observed after peritoneal dialysis technique failure is due to high comorbidity of these patients or the technique failure itself causes higher mortality. This study will use the existing data in the United States Renal Data System (USRDS) Dialysis Morbidity and Mortality Studies (DMMS). The comorbidity tool will be developed from a subset of the 6300 prevalent patients in the DMMS III study. By Cox proportional hazards, the relative risk for death, for each of the comorbid conditions will be determined and scores will be given based on the relative risk. This scoring system will be validated in the following sub-populations: prevalent hemodialysis patients with Medicare as the primary or sole payer in the DMMS-IV study, prevalent hemodialysis patients with non-Medicare as the primary or sole payer in the DMMS-IV study, incident hemo and peritoneal dialysis started on dialysis in 1996 or 1997 in the DMMS wave II study irrespective of the insurance status. The outcomes of interest will be hospital days and Medicare hospital costs (by ANOVA) and death (by Cox proportional hazards). Further data from DMMS II will be used to examine the risk of death of incident peritoneal dialysis patients who failed the technique with incident hemodialysis patients. As comorbidity predicts peritoneal dialysis technique failure, the above analysis will help in determining the optimal dialysis modality based on comorbidity at the initiation of dialysis.