Rawles J, Light J
Medicines Assessment Research Unit, University of Aberdeen, Foresterhill.
J Epidemiol Community Health. 1993 Oct;47(5):377-81. doi: 10.1136/jech.47.5.377.
(1) To measure the quality of life and the loss of quality adjusted days (QADS) after suspected acute myocardial infarction in patients who received thrombolytic treatment either at home or in hospital. (2) To compare the loss of QADS as a trial endpoint with the conventional endpoints of mortality and Q-wave infarction.
Randomised double blind parallel group trial of anistreplase (30 U given intravenously) and placebo given either at home or in hospital.
Rural practices in Grampian admitting patients to teaching hospitals in Aberdeen.
A total of 311 patients with suspected acute myocardial infarction and no contraindications to thrombolytic treatment seen at home within four hours of the onset of symptoms.
Loss of quality adjusted days (QADS) in the first 100 days after suspected myocardial infarction (365 QADS = 1 QALY) was the main outcome measure. Compared with later administration in hospital, anistreplase at home resulted in a relative reduction of mortality of 49% (95% confidence interval 3.95%, 2p = 0.04), and a relative reduction of 26% in the proportion of survivors with infarction who had Q-waves (95% CI 7.44%, 2p = 0.007). During the 100 day follow up, the median loss of QADS was 25 for all patients. This loss was significantly greater in those who died than in survivors (65 v 18, 2p < 0.001), and in survivors with infarction than in survivors without infarction (26 v 13, 2p < 0.01). However, there was no significant difference in loss of QADS in those with infarction with or without Q-waves (29 v 21, NS), and the median loss of QADS was not significantly different in those who had thrombolytic treatment at home or in hospital (median difference 0, 95% CI -5, +4 QADS).
Loss of QADS had two serious limitations as an outcome measure: it was less sensitive than mortality and it failed to reflect physiological benefit. Palliative treatment with no physiological effect would have resulted in a greater gain in QADS (or QALYs) than did early thrombolytic treatment. Extreme caution is required in accepting a gain in QALYs as a valid outcome measure for health care.
(1)测量在家或在医院接受溶栓治疗的疑似急性心肌梗死患者的生活质量及质量调整生命天数(QADS)损失。(2)将QADS损失作为试验终点与传统的死亡率和Q波梗死终点进行比较。
阿尼普酶(静脉注射30单位)与安慰剂在家或在医院应用的随机双盲平行组试验。
格兰扁地区农村诊所,将患者收治入阿伯丁的教学医院。
共311例疑似急性心肌梗死且在症状发作后4小时内在家中就诊、无溶栓治疗禁忌证的患者。
疑似心肌梗死后前100天的质量调整生命天数(QADS)损失(365个QADS = 1个质量调整生命年)是主要测量指标。与在医院延迟给药相比,在家应用阿尼普酶使死亡率相对降低49%(95%置信区间3.95%,P = 0.04),有Q波梗死的存活者比例相对降低26%(95%置信区间7.44%,P = 0.007)。在100天随访期间,所有患者QADS损失的中位数为25。死亡患者的这一损失显著大于存活者(65对18,P < 0.001),有梗死的存活者大于无梗死的存活者(26对13,P < 0.01)。然而,有Q波和无Q波梗死患者的QADS损失无显著差异(29对21,无显著性),在家或在医院接受溶栓治疗患者的QADS损失中位数无显著差异(中位数差异0,95%置信区间 -5,+4个QADS)。
QADS损失作为一项测量指标有两个严重局限性:它不如死亡率敏感,且未能反映生理益处。无生理效应的姑息治疗相比早期溶栓治疗会使QADS(或质量调整生命年)有更大提升。在将质量调整生命年的提升作为医疗保健的有效测量指标时需极度谨慎。