University of Toronto Lupus Clinic and the Centre for Prognosis Studies in the Rheumatic Diseases, Toronto Western Hospital, 399 Bathurst Street, Toronto, ON, M5T 2S8, Canada.
Arthritis Res Ther. 2011;13(5):R156. doi: 10.1186/ar3473. Epub 2011 Sep 29.
Previous studies have shown that traditional risk factors such as hypercholesterolemia and hypertension account for only a small proportion of the dramatically increased risk of atherosclerotic coronary artery disease (CAD) in systemic lupus erythematosus (SLE). However, in these studies, exposure to risk factors was measured only at baseline. In this study, our objective was to compare measures of cumulative exposure with remote and recent values for each of total cholesterol (TC), systolic (SBP), and diastolic (DBP) blood pressure in terms of ability to quantify risk of atherosclerotic CAD in patients with SLE.
Patients in the Toronto lupus cohort had TC and BP measured at each clinic visit and were followed up prospectively for the occurrence of CAD. For each patient, arithmetic mean, time-adjusted mean (AM) and area-under-the-curve (AUC) were calculated for serial TC, SBP, and DBP measurements. Proportional hazards regression models were used to compare these summary measures with recent and first-available ("remote") measurements in terms of ability to quantify risk of CAD events, defined as myocardial infarction, angina, or sudden cardiac death.
The 991 patients had a mean ± SD of 19 ± 19 TC measurements per patient. Over a follow-up of 6.7 ± 6.4 years, 86 CAD events occurred; although remote TC was not significantly predictive of CAD, mean and AM TC were more strongly predictive (hazard ratio (HR) 2.07; P = 0.003) than recent TC (HR 1.86, P = 0.001). AUC TC was not predictive of CAD. A similar pattern was seen for DBP and SBP. Older age, male sex, higher baseline and recent disease activity score, and corticosteroid use also increased CAD risk, whereas antimalarials were protective.
In contrast to the population-based Framingham model, first-available TC and BP are not predictive of CAD among patients with SLE, in whom measures reflecting cumulative exposure over time are better able to quantify CAD risk. This is an important consideration in future studies of dynamic risk factors for CAD in a chronic relapsing-remitting disease such as SLE. Our findings also underpin the importance of adequate control of SLE disease activity while minimizing corticosteroid use, and highlight the cardioprotective effect of antimalarials.
先前的研究表明，在系统性红斑狼疮（SLE）患者中，动脉粥样硬化性冠心病（CAD）的风险显著增加，而传统的危险因素如高胆固醇血症和高血压仅占很小一部分。然而，在这些研究中，危险因素的暴露仅在基线时进行测量。在这项研究中，我们的目的是比较累积暴露的测量值与总胆固醇（TC）、收缩压（SBP）和舒张压（DBP）的远程和近期值，以量化 SLE 患者发生动脉粥样硬化性 CAD 的风险。
多伦多狼疮队列中的患者在每次就诊时测量 TC 和血压，并进行前瞻性随访以确定 CAD 的发生。对于每个患者，计算 TC、SBP 和 DBP 的系列测量值的算术平均值（AM）和曲线下面积（AUC）。使用比例风险回归模型比较这些汇总测量值与最近和首次可用（“远程”）测量值在定量 CAD 事件风险方面的能力，CAD 事件定义为心肌梗死、心绞痛或心源性猝死。
991 例患者的每位患者平均有 19 ± 19 次 TC 测量值。在 6.7 ± 6.4 年的随访期间，发生了 86 例 CAD 事件；尽管远程 TC 对 CAD 无明显预测作用，但均值和 AM TC 比近期 TC（HR 2.07；P = 0.003）更具预测性（HR 1.86，P = 0.001）。TC 的 AUC 不能预测 CAD。DBP 和 SBP 也出现了类似的模式。年龄较大、男性、较高的基线和近期疾病活动评分以及皮质类固醇的使用也增加了 CAD 风险，而抗疟药具有保护作用。
与基于人群的弗雷明汉模型相反，SLE 患者的首次可用 TC 和 BP 不能预测 CAD，而反映随时间累积暴露的测量值更能定量 CAD 风险。这在未来研究 SLE 等慢性复发性缓解性疾病的 CAD 动态危险因素时是一个重要的考虑因素。我们的研究结果还强调了在 SLE 疾病活动中充分控制的重要性，同时尽量减少皮质类固醇的使用，并突出了抗疟药的心脏保护作用。
