Background: Patients with transthyretin (TTR) cardiac amyloidosis demonstrate cardiac cachexia with progression of their cardiomyopathy, which is characterised by malnutrition and a heightened inflammatory state. How best to measure this condition is less well characterised. We investigated differences in survival among patients with ATTR cardiac amyloidosis by nutritional status as defined by modified BMI (mBMI) and by inflammatory state as defined by serum uric acid.

Methods and results: This study was a retrospective analysis of patients diagnosed with ATTR cardiac amyloidosis at a single tertiary medical centre. Baseline characteristics were compared by nutritional status as measured by mBMI and by inflammatory state as measured by serum uric acid. Kaplan-Meier survival analyses were used to compare nutritional status and inflammatory status for the composite outcome of death. Cox proportional hazards modelling was used to assess predictors of death in this cohort. Three hundred patients (mean age 75 ± 11) years, 84.3% male) were included. Those with low mBMI (<1185 kg/m² g/L) had shorter time to death (5.4 vs. 6.8 years, log rank p = .045) and those with elevated serum uric acid (>8.8 mg/dL) had shorter time to death (4.9 vs. 7.7 years, log rank p < .0001). Those with both low mBMI and elevated serum uric acid had the shortest time to death (4.3 years, log rank p = .005). In this cohort, mBMI was not a univariate predictor of death though there was a trend towards significance (HR 0.92, per 100 kg/m² g/L, 95% CI 0.828–1.016, p = .099). Serum uric acid was a univariate predictor of death (HR 1.27 per 1 mg/dL, 95% CI 1.114–1.455, p < .001). In multivariate Cox analysis, this association remained significant (HR 1.31 per 1 mg/dL increase, 95% CI 1.096–1.560, p = .003) as well as in a separate stepwise model controlling for potential confounders including daily diuretic use, uric acid lowering therapy, and renal dysfunction.

Conclusions: Both nutritional status as measured by mBMI and inflammation as measured by serum uric acid are associated with survival in patients with TTR cardiac amyloidosis however only serum uric acid is an independent predictor of death.

背景：运甲状腺素蛋白（TTR）心脏淀粉样变性患者表现出心脏恶病质，并伴有心肌病进展，其特征在于营养不良和炎症状态加剧。如何最好地测量这种情况的特征不太明确。我们调查了ATTR心脏淀粉样变性患者的生存差异，其中营养状态由改良的BMI（mBMI）定义，炎症状态由血清尿酸定义。

方法和结果：这项研究是对单个三级医疗中心诊断为ATTR心脏淀粉样变性病的患者进行的回顾性分析。基线特征通过mBMI测量的营养状态和血清尿酸测量的炎症状态进行比较。Kaplan-Meier生存分析用于比较营养状况和炎症状况，以评估死亡的综合结果。使用Cox比例风险建模来评估该队列中死亡的预测因子。包括三百例患者（平均年龄75±11）岁，男性84.3％。mBMI低（<1185 kg / m ² g / L）的人的死亡时间更短（5.4 vs. 6.8年，对数等级p = .045），而血清尿酸水平升高（> 8.8 mg / dL）的患者的死亡时间较短（4.9年与7.7年，对数秩p  <.0001）。mBMI值低和血清尿酸升高的患者死亡时间最短（4.3年，对数秩p  = .005）。在该队列中，尽管存在显着趋势，但mBMI不是死亡的单因素预测因子（HR 0.92，每100 kg / m ² g / L，95％CI 0.828-1.016，p  = .099）。血清尿酸是死亡的单因素预测因子（HR 1.27 / 1 mg / dL，95％CI 1.114–1.455，p  <.001）。在多变量Cox分析中，这种关联仍然显着（每增加1 mg / dL HR 1.31，95％CI 1.096–1.560，p = 0.003），并在单独的逐步模型中控制潜在的混杂因素，包括每日利尿剂使用，降低尿酸治疗和肾功能不全。

结论：通过mBMI测定的营养状况和通过血清尿酸测定的炎症都与TTR心脏淀粉样变性患者的存活率相关，但是只有血清尿酸是死亡的独立预测因子。