EPIUnit - Instituto de Saúde Pública, Universidade do Porto, Porto, Portugal.
Departamento de Ciências da Saúde Pública e Forenses e Educação Médica, Faculdade de Medicina da Universidade do Porto, Portugal.
Nephrology (Carlton). 2020 Dec;25(12):897-905. doi: 10.1111/nep.13768. Epub 2020 Sep 7.
With the use of a joint model (JM) we investigated how different definitions of baseline serum creatinine (SCr) would affect the association between an acute increase in inpatients' SCr and 30-day mortality and whether this effect depends on premorbid SCr trajectory.
This was a retrospective study including adult patients admitted to a tertiary acute-care hospital in Porto, Portugal, between January 1, 2013, and December 31, 2015, who had at least two preadmission ambulatory and two inpatients SCr measurements. The baseline SCr was defined as the lowest (-min), the most recent (-last) or the median (-medi) value over the preadmission period. The JM combined a linear mixed model for repeated inpatient SCr relative to baseline value and a Cox proportional survival model. Preadmission SCr courses were identified using linear regression and subsequently clustered based upon a patient-specific slope. Preadmission SCr trajectories were described as median SCr courses within clusters.
SCr trajectories were: "Stable" (78.0% of patients), "Decreasing" (11.3%) and "Increasing" (10.7%). Overall, an increase in inpatient SCr by 50% relative to baseline SCr-min raised the risk of 30-day mortality by 74%; the estimate was not different from hazard ratio (HR) obtained for SCr-last (1.78) and SCr-medi (1.71). We found no differences in HR across preadmission trajectories.
The increased risk of death associated with an abrupt rise in inpatient SCr depends neither on the definition of baseline SCr nor patients' SCr trajectory before hospitalisation. Preadmission SCr-medi value may be the least biased estimate of the baseline renal function.
通过联合模型（JM），我们研究了不同的基线血清肌酐（SCr）定义如何影响住院患者 SCr 急性升高与 30 天死亡率之间的关系，以及这种影响是否取决于发病前 SCr 轨迹。
这是一项回顾性研究，纳入了 2013 年 1 月 1 日至 2015 年 12 月 31 日期间在葡萄牙波尔图的一家三级急性护理医院住院的成年患者，这些患者至少有两次就诊前的门诊和两次住院 SCr 测量值。基线 SCr 定义为最低值（-min）、最近值（-last）或就诊前期间的中位数（-medi）值。JM 联合了一个用于重复住院 SCr 相对于基线值的线性混合模型和一个 Cox 比例生存模型。使用线性回归识别就诊前 SCr 曲线，然后根据患者特定斜率对其进行聚类。在聚类中描述就诊前 SCr 轨迹为中位数 SCr 曲线。
SCr 轨迹为：“稳定”（78.0%的患者）、“下降”（11.3%）和“上升”（10.7%）。总的来说，相对于基线 SCr-min，住院 SCr 增加 50%会使 30 天死亡率的风险增加 74%；这一估计与 SCr-last（1.78）和 SCr-medi（1.71）获得的危险比（HR）没有差异。我们在就诊前的轨迹中没有发现 HR 的差异。
与住院患者 SCr 急剧升高相关的死亡风险既不取决于基线 SCr 的定义，也不取决于患者住院前的 SCr 轨迹。就诊前 SCr-medi 值可能是基线肾功能最无偏估计值。
