Most epidemiological studies of ARF in the critically ill have been based at single centers, or have examined exposures at single time points using discrete outcomes( e. g., in-hospital mortality).

• 危重病ARF大部分流行病学研究都建立在单中心研究基础上，或者利用不连续资料结果（患者住院死亡率）单个时间点暴露获得。