Introduction

Great part of Chagas disease (ChD) mortality occurs due to ventricular arrhythmias, and autonomic function (AF) may predict unfavorable outcomes. We aimed to evaluate the predictive value of AF indexes in ChD patients.

Methods

The Bambuí Study of Aging is a prospective cohort of residents ≥60 years at study onset (1997), in the southeastern Brazilian city of Bambuí (15,000 inhabitants). Consented participants underwent annual follow-up visits, and death certificates were tracked. AF was assessed by the maximum expiration on minimum inspiration (E:I) ratio during ECG acquisition and by heart rate variability indices: SDRR (standard deviation of adjacent RR intervals) and RMSSD (square root of the mean of the sum of squares of the differences between adjacent RR intervals)), calculated using a computer algorithm. Cox proportional hazards regression was performed to access the prognostic value of AF indexes, expressed as terciles, for all-cause mortality, after adjustment for demographic, clinical and ECG variables.

Results

From 1742 qualifying residents, 1000 had valid AF tests, being 321 with ChD. Among these, median age was 68 (64–74) years, and 32.5% were men. In Cox survival analyses, only SDRR was associated with all-cause mortality in non-adjusted models: SDRR (hazard ratio (HR): 1.26 (95% CI 1.08–1.47), p < 0.001), E:I ratio (HR: 1.13 (95% CI 0,98–1.31), p = 0.10) and RMSSD (HR: 0.99 (0.86–1.16), p = 0.95). After adjustment for sex and age, none of the indexes remained as independent predictors.

Conclusion

Among elderly patients with ChD, AF indexes available in this cohort were not independent predictors of 14-year mortality.

中文翻译：

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恰加斯病患者的迷走神经自主神经功能障碍和死亡率：老年人群的 14 年结果

介绍

恰加斯病 (ChD) 死亡的很大一部分是由于室性心律失常所致，而自主神经功能 (AF) 可能会预测不利的结果。我们的目的是评估 AF 指数对 ChD 患者的预测价值。

方法

Bambuí 老龄化​​研究是对巴西东南部城市 Bambuí（15,000 名居民）进行研究时（1997 年）年龄≥60 岁的居民的前瞻性队列。同意的参与者接受年度随访，并追踪死亡证明。AF 通过 ECG 采集期间的最大呼气与最小吸气 (E:I) 比率以及心率变异性指数进行评估：SDRR（相邻 RR 间隔的标准差）和 RMSSD（RR 间隔的平方和平均值的平方根）相邻 RR 间隔之间的差异）），使用计算机算法计算。在调整人口、临床和心电图变量后，进行Cox比例风险回归，以获取 AF 指数（以三分位数表示）对全因死亡率的预后价值。

结果

在 1742 名符合资格的居民中，有 1000 人进行了有效的 AF 测试，其中 321 人患有 ChD。其中，中位年龄为 68（64-74）岁，其中 32.5% 为男性。在 Cox 生存分析中，在非调整模型中，只有 SDRR 与全因死亡率相关：SDRR（风险比 (HR)：1.26 (95% CI 1.08–1.47)，p  < 0.001），E:I 比（HR： 1.13 (95% CI 0.98–1.31), p  = 0.10) 和 RMSSD (HR: 0.99 (0.86–1.16), p  = 0.95)。在对性别和年龄进行调整后，没有任何指数仍然可以作为独立的预测因子。

结论

在患有 ChD 的老年患者中，该队列中可用的 AF 指数并不是 14 年死亡率的独立预测因子。