McAlister F A, O'Connor A M, Wells G, Grover S A, Laupacis A
Division of General Internal Medicine, University of Alberta, Edmonton.
CMAJ. 2000 Aug 22;163(4):403-8.
Hypertension guidelines from different organizations often specify different treatment thresholds, and none explicitly state how these thresholds were chosen. This study was undertaken to determine the treatment thresholds of family physicians and hypertensive patients for mild, uncomplicated essential hypertension. A subject's treatment threshold can be determined by eliciting the minimum reduction in cardiovascular risk that he or she feels outweighs the inconvenience, costs and side effects of antihypertensive therapy (the minimal clinically important difference [MCID]).
The study subjects consisted of a random sample of family physicians and a consecutive sample of hypertensive patients without overt cardiovascular disease from Ottawa and Edmonton. To determine participants' MCIDs, we used a survey employing hypothetical scenarios (each depicting a different baseline cardiovascular risk) and a probability trade-off tool.
Of 94 family physicians and 146 patients approached for the study, 72 and 74 participated respectively. There was marked variability in the MCIDs of both groups. In general, patients were less likely to want antihypertensive therapy than physicians, particularly when baseline cardiovascular risks were low: 49% v. 64% (p = 0.06), 68% v. 92% (p < 0.001) and 86% v. 100% (p = 0.001) for 5-year cardiovascular risks of 2%, 5% and 10% respectively. Moreover, patients expressed larger MCIDs (i.e., wanted greater benefits before accepting therapy) than physicians. However, a subgroup of patients (15% to 26%, depending on the scenario) wanted treatment even if there was no anticipated benefit. Multivariate analysis showed that no sociodemographic factors strongly predicted the MCIDs of either group.
Guidelines that set treatment thresholds on the basis of physician or expert opinion may not accurately reflect the preferences of hypertensive patients. There is a need for patient decision aids and attention to patient preferences when initiation of antihypertensive therapy is considered for the prevention of cardiovascular disease. Further research is needed to define treatment thresholds for other chronic conditions and in other groups.
不同组织制定的高血压指南往往规定了不同的治疗阈值，且均未明确说明这些阈值是如何选定的。本研究旨在确定家庭医生和高血压患者对于轻度、无并发症的原发性高血压的治疗阈值。受试者的治疗阈值可通过引出其认为能超过降压治疗带来的不便、成本和副作用的最小心血管风险降低幅度来确定（最小临床重要差异[MCID]）。
研究对象包括来自渥太华和埃德蒙顿的家庭医生随机样本以及无明显心血管疾病的高血压患者连续样本。为确定参与者的MCID，我们使用了一项采用假设情景（每个情景描述不同的基线心血管风险）和概率权衡工具的调查。
在邀请参与研究的94名家庭医生和146名患者中，分别有72名和74名参与。两组的MCID均存在显著差异。总体而言，患者比医生更不愿意接受降压治疗，尤其是当基线心血管风险较低时：5年心血管风险分别为2%、5%和10%时，患者接受治疗的比例分别为49%对64%（p = 0.06）、68%对92%（p < 0.001）和86%对100%（p = 0.001）。此外，患者表示的MCID比医生更大（即接受治疗前希望获得更大益处）。然而，有一小部分患者（15%至26%，取决于情景）即使预计无益处也希望接受治疗。多变量分析表明，没有社会人口统计学因素能强烈预测两组的MCID。
基于医生或专家意见设定治疗阈值的指南可能无法准确反映高血压患者的偏好。在考虑启动降压治疗以预防心血管疾病时，需要患者决策辅助工具并关注患者偏好。需要进一步研究来确定其他慢性病和其他人群的治疗阈值。
