Bjørn M, Brendstrup C, Karlsen S, Carlsen J E
Project Group, Medicon Clinical Research, Allerød, Denmark.
J Card Fail. 1998 Sep;4(3):225-30; discussion 231. doi: 10.1016/s1071-9164(98)80009-2.
Trials usually do little or nothing to ensure random samples of patients representative of the disease under investigation.
To evaluate the effects of consecutive screening and enrollment, we compared the demographic characteristics of patients from three interventional trials, applying consecutive screening with those from nine similar survival trials of risk-stratified patients with either myocardial infarct or congestive heart failure. Administrative information was also compared. Patients in the consecutive studies were 5-10 years older and more often female. Six of the nine conventional studies enrolling high-risk patients had a 1-year mortality of < or =10% compared with 22-28% in the consecutive studies. The conventional studies that accounted for screenings tended to screen four to six times more patients, but typically enrolled fewer of those screened: 4-7% versus 17-26% in the consecutive studies. The conventional studies excluded the majority of those eligible, up to 85% versus 35% in consecutive studies. The conventional studies enrolled less than 1 patient per center per month compared with two to four times as many in the consecutive studies.
Patients in conventional cardiovascular trials, not using consecutive screening are selected and not representative of the disease under investigation. They are younger, more often male, and have lower risk. This makes such trials less reliable and useful. It prolongs the length of a trial study and makes it more expensive. Consecutive screening and enrollment are feasible and offer a detailed description of the patient selection The consecutive principles contribute to representative patient samples and should be mandatory in future clinical trials.
试验通常很少或根本不采取措施来确保所选取的患者随机样本能够代表所研究的疾病。
为评估连续筛查和入组的效果，我们比较了三项介入性试验中采用连续筛查的患者的人口统计学特征，这些患者来自心肌梗死或充血性心力衰竭的风险分层患者的九项类似生存试验。同时还比较了管理信息。连续研究中的患者年龄大5至10岁，女性比例更高。九项纳入高危患者的传统研究中有六项1年死亡率≤10%，而连续研究中的这一比例为22%至28%。考虑筛查因素的传统研究筛查的患者数量往往是连续研究的四至六倍，但通常纳入的筛查患者较少：连续研究中为17%至26%，而传统研究中为4%至7%。传统研究排除了大多数符合条件的患者，连续研究中这一比例为35%，而传统研究中高达85%。传统研究每个中心每月纳入的患者不到1名，而连续研究中这一数量是其两到四倍。
未采用连续筛查的传统心血管试验所选取的患者不能代表所研究的疾病。这些患者更年轻，男性比例更高，风险更低。这使得此类试验的可靠性和实用性降低。它延长了试验研究的时间，增加了成本。连续筛查和入组是可行的，并且能够详细描述患者的选择情况。连续原则有助于获得具有代表性的患者样本，在未来的临床试验中应成为强制性要求。
