MRC Epidemiology Unit, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK.
Diabetologia. 2013 May;56(5):1004-11. doi: 10.1007/s00125-013-2854-8. Epub 2013 Feb 12.
AIMS/HYPOTHESIS: HbA1c is an important risk factor for cardiovascular disease (CVD), with 1% higher HbA1c levels associated with a 10-20% increased risk of CVD. Little is known about the association between change in HbA1c over time and cardiovascular risk in non-diabetic populations. This study examined the association between change in HbA1c over time and cardiovascular risk in a non-diabetic British population.
We used data on HbA1c collected at baseline and at a second health examination 3 years later among a population of 5,790 non-diabetic men and women who participated in the European Prospective Investigation of Cancer (EPIC)-Norfolk. The association between change in HbA1c over 3 years and incident cardiovascular events over the following 8 years was examined using multivariate Cox regression. We also examined whether information on change in HbA1c over time improved prediction of cardiovascular events over a single measure of HbA1c by comparing the area under the receiver operating characteristic curves (aROC) and computing the net reclassification improvement.
The mean change (SD) in HbA1c over 3 years was 0.13% (0.52). During 44,596 person-years of follow-up, 529 cardiovascular events occurred (incidence 11.9 per 1,000 person-years). Each 0.5% rise in HbA1c over 3 years was associated with a 9% increase in risk of a cardiovascular event (HR 1.09; 95% CI 1.01, 1.18) after adjustment for baseline HbA1c and other major cardiovascular risk factors. However, change in HbA1c was not associated with cardiovascular risk after adjustment for HbA1c at follow-up. Multivariate models with and without information on change in HbA1c over time showed a similar aROC of 0.78. Adding change in HbA1c to the model with HbA1c at follow-up did not improve risk classification.
CONCLUSIONS/INTERPRETATION: Addition of information on change in HbA1c over 3 years did not improve the prediction of CVD over and above information on HbA1c and other major cardiovascular risk factors from a single time point.
目的/假设：HbA1c 是心血管疾病（CVD）的一个重要危险因素，HbA1c 每升高 1%，CVD 风险就增加 10-20%。关于非糖尿病人群中 HbA1c 随时间的变化与心血管风险之间的关系知之甚少。本研究旨在探讨非糖尿病英国人群中 HbA1c 随时间的变化与心血管风险之间的关系。
我们使用了参加欧洲癌症前瞻性调查（EPIC）-诺福克的 5790 名非糖尿病男性和女性在基线和 3 年后第二次健康检查时收集的 HbA1c 数据。使用多变量 Cox 回归分析了 3 年内 HbA1c 的变化与随后 8 年内心血管事件的发生之间的关系。我们还通过比较接受者操作特征曲线下面积（aROC）和计算净重新分类改善来检查随时间变化的 HbA1c 信息是否可以改善对单一 HbA1c 测量的心血管事件预测。
3 年内 HbA1c 的平均变化（SD）为 0.13%（0.52）。在 44596 人年的随访期间，发生了 529 例心血管事件（发生率为 11.9/1000 人年）。在调整了基线 HbA1c 和其他主要心血管危险因素后，HbA1c 每升高 0.5%，心血管事件的风险增加 9%（HR 1.09；95%CI 1.01，1.18）。然而，调整随访时的 HbA1c 后，HbA1c 的变化与心血管风险无关。有和没有随时间变化的 HbA1c 信息的多变量模型的 aROC 相似，均为 0.78。将 HbA1c 随时间的变化加入到仅包含随访时 HbA1c 的模型中并不能改善风险分类。
结论/解释：HbA1c 随时间的变化信息的加入并不能改善基于单一时间点的 HbA1c 和其他主要心血管危险因素的 CVD 预测。
