Departments of *Epidemiology, Gillings School of Global Public Health †Medicine, Division of Nephrology and Hypertension ‡Medicine, Division of Infectious Diseases, University of North Carolina, Chapel Hill, NC.
Med Care. 2013 Dec;51(12):1106-13. doi: 10.1097/MLR.0b013e3182a50297.
Observational studies of preventive medications, such as vaccinations, can suffer from the healthy-user bias because vaccinated patients may be healthier than unvaccinated patients. Indicators of health status and frailty suitable for attenuating this bias could be identified in administrative data.
To examine the association of baseline variables and time-dependent hospitalization and skilled nursing care with the receipt of influenza vaccination in patients with end-stage renal disease.
Observational cohort study using United States Renal Data System files each year from 1999 to 2005.
Population-based cohorts that included >115,000 adult, hemodialysis patients each year.
We estimated hazard ratios for the association of baseline variables and time-dependent hospitalization days and skilled nursing days with influenza vaccination, controlling for demographic and baseline health status variables.
Vaccination coverage increased from 47% in 1999 to 60% in 2005. Patients with any length of hospitalization were less likely to be vaccinated, however, the association was stronger in patients with longer stays [15-25 d: hazard ratio=0.64 (95% confidence interval, 0.62-0.65); 26-30 d: 0.40 (0.38-0.42)]. Patients with any length of skilled nursing care of >1 day had similar estimates; these patients were also less likely to be vaccinated [26-30 d: 0.66 (0.64-0.69)].
Patients with long hospitalizations or skilled nursing stays were less likely to be vaccinated suggesting evidence of the healthy-user effect. These variables could be used to account for bias in studies of preventive services in patients on dialysis.
预防性药物（如疫苗）的观察性研究可能受到健康使用者偏差的影响，因为接种疫苗的患者可能比未接种疫苗的患者更健康。适合减轻这种偏差的健康状况和脆弱性指标可以在行政数据中确定。
研究终末期肾病患者的基线变量和随时间变化的住院和熟练护理与接受流感疫苗接种之间的关系。
使用美国肾脏数据系统文件进行的观察性队列研究，每年从 1999 年到 2005 年。
每年包括>115,000 名成年血液透析患者的基于人群的队列。
我们估计了基线变量和随时间变化的住院天数和熟练护理天数与流感疫苗接种之间的关联的风险比，同时控制了人口统计学和基线健康状况变量。
疫苗接种率从 1999 年的 47%增加到 2005 年的 60%。任何长度的住院患者接种疫苗的可能性较低，但是在住院时间较长的患者中，这种关联更强[15-25 天：风险比=0.64（95%置信区间，0.62-0.65）；26-30 天：0.40（0.38-0.42）]。有任何长度的>1 天熟练护理的患者也有类似的估计值；这些患者也不太可能接种疫苗[26-30 天：0.66（0.64-0.69）]。
长期住院或熟练护理的患者接种疫苗的可能性较低，这表明存在健康使用者效应的证据。这些变量可用于解释透析患者预防性服务研究中的偏差。
