Journal of clinical epidemiology
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Whiplash injury, common after a motor vehicle crash, has a variable prognosis that is difficult to predict. To assess the role of various factors on this prognosis, we assembled a historical cohort of 3014 individuals who sustained a whiplash injury resulting from a motor vehicle crash in the Province of Quebec, Canada, in 1987 and were followed for 6 years. The data were obtained from the computerized databases created by the province's universal automobile insurance plan and police accident reports. ⋯ Subjects with a score of 0 to 2, that is those who had at most two risk factors present, had the fastest median recovery time of 19 days compared with 71 days for subjects who had a score of 6 or more. We conclude that several sociodemographic and crash-related factors are independently associated with a slow and costly recovery from whiplash injury. They are easily measurable at the time of the crash and combined so as to be simply incorporated in intervention programs aimed at early identification and management of whiplash patients with a poor prognosis.
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Comparative Study
Aminorex, dexfenfluramine, and primary pulmonary hypertension.
In the late 1960s, an epidemic of primary pulmonary hypertension (PPH) occurred in Europe shortly after the introduction of aminorex fumarate, a potent anorexigen. A recently published case-control study from Europe reported that use of other anorexigens (the most prevalent of which was dexfenfluramine) was also associated with an increased risk of PPH. This led to warnings of a repeat epidemic, especially after the introduction of dexfenfluramine on the North American market. ⋯ The strong association between aminorex and PPH probably led to a 5-fold increase in PPH incidence, and thus a very noticeable epidemic. The association with dexfenfluramine would result in an increase in incidence of only 20%. Based on the available evidence, a repeat PPH epidemic seems unlikely.
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Comparative Study
Body mass index compared to dual-energy x-ray absorptiometry: evidence for a spectrum bias.
The objective of this study was to evaluate the accuracy of body mass index (BMI) in the diagnosis of obesity. The relationship of this weight-for-height index to body composition was determined using dual-energy x-ray absorptiometry (DEXA) in 226 Caucasian subjects. BMI-obesity was defined as a BMI greater than 27.8 kg/m2 in males and greater than 27.3 kg/m2 in females. ⋯ When analyzing subgroups of subjects according to weight, sensitivity was higher among heavier subjects than among lighter ones. In both sexes and in all subgroups, the specificity was 100%. The clinical implication of this spectrum bias is that, in men or women weighing less than 80 kg, measures of obesity other than BMI, such as bioelectrical impedance, should be preferred.
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To determine eligibility for a (randomized) clinical trial, measuring the inclusion and exclusion criteria can be extended over a period of time. During this period, known as the selection period, a patient is repeatedly examined at certain time intervals. This study describes an approach for optimizing the efficiency of the selection period. ⋯ As the initial costs per randomization were $1444, there would be a 3.6% (52/1444) savings in recruitment costs under the prediction models, accounting for a savings of more than $450,000. We conclude that the use of data obtained early in a selection period can predict subsequent exclusions, and therefore could increase the efficiency of such a period. The approach could be applied to data obtained in a pilot study as well as data obtained in the beginning of a prolonged intake period.