QT prolongation is a risk factor for life-threatening arrhythmias and sudden cardiac death. In large cohorts, QT interval was associated with all-cause mortality, but these analyses may contain residual confounding. Whether the QT interval provides prognostic information above and beyond a validated mortality risk score is unknown. We hypothesized that QT interval on ECG will independently predict mortality after adjustment for the Care Assessment Needs (CAN) score, which was validated to predict mortality nationwide at the Veterans Administration (VA) (c-index 0.86). Outpatients with an ECG at the Minneapolis VA from 2012 to 2016 were included in this retrospective cohort study. ECGs with ventricular rate < 50 or > 100 beats/min and those with QRS > 120 ms were excluded. QT intervals were corrected (QTc) using the Bazett's formula. CAN score, calculated within 1-week of the ECG, was obtained from the VA Corporate Data Warehouse. Of the 31,201 patients, 427 (1.4%) had QTc ≥ 500 ms, 1799 (5.8%) had QTc 470–500 ms and 28,975 (92.9%) had QTc < 470 ms. Compared to those with QTc < 470 ms, CAN-adjusted odds ratios (OR) for 1-year mortality (1.76 for QTc 470–500 and 2.70 for QTc > 500 ms; < 0.0001 for both) and for 5-year mortality (1.75 for QTc 470–500 and 2.48 for QTc > 500 ms; p < 0.0001 for both) were significantly higher in those with longer QTc. C-index for CAN score and QTc predicting 1-year mortality was 0.837. QT prolongation predicts all-cause mortality independently of a validated mortality risk prediction score.

中文翻译：

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QT 延长预测全因死亡率高于经过验证的风险评分

QT 延长是危及生命的心律失常和心源性猝死的危险因素。在大型队列中，QT 间期与全因死亡率相关，但这些分析可能包含残留的混杂因素。QT 间期是否能提供高于经过验证的死亡风险评分的预后信息尚不清楚。我们假设在调整护理评估需求 (CAN) 评分后，心电图 QT 间期将独立预测死亡率，该评分经退伍军人管理局 (VA) 验证可预测全国范围内的死亡率（c 指数 0.86）。这项回顾性队列研究纳入了 2012 年至 2016 年在明尼阿波利斯 VA 进行心电图检查的门诊患者。排除心室率 < 50 或 > 100 次/分钟以及 QRS > 120 ms 的心电图。使用 Bazett 公式校正 QT 间期 (QTc)。CAN 评分是在心电图检查后 1 周内计算得出，是从 VA 公司数据仓库获得的。在 31,201 名患者中，427 名 (1.4%) 患者 QTc ≥ 500 ms，1799 名 (5.8%) QTc 470–500 ms，28,975 名 (92.9%) QTc < 470 ms。与 QTc < 470 ms 的患者相比，CAN 调整后的 1 年死亡率（QTc 470-500 为 1.76，QTc > 500 ms 为 2.70；均 < 0.0001）和 5 年死亡率（1.75对于 QTc 470-500 的患者，QTc > 500 ms 的患者为 2.48；两者的 p < 0.0001）在 QTc 较长的患者中显着较高。CAN 评分和 QTc 预测 1 年死亡率的 C 指数为 0.837。QT 延长可独立于经过验证的死亡风险预测评分来预测全因死亡率。