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BMJ No 7098 Volume 314 Papers - Abstracts Saturday 28 June 1997
Corticosteroids in acute traumatic brain injury: systematic
review of randomised controlled trials
Corticosteroids in acute traumatic brain injury: systematic review of randomised controlled trialsPhilip Alderson, Ian Roberts AbstractObjectives: To quantify the effectiveness and safety of corticosteroids in the treatment of acute traumatic brain injury.Design: Systematic review of randomised controlled trials of corticosteroids in acute traumatic brain injury. Summary odds ratios were estimated as an inverse variance weighted average of the odds ratios for each study. Setting: Randomised trials available by March 1996. Subjects: The included trials with outcome data comprised 2073 randomised participants. Results: The effect of corticosteroids on the risk of death was reported in 13 included trials. The pooled odds ratio for the 13 trials was 0.91 (95% confidence interval 0.74 to 1.12). Pooled absolute risk reduction was 1.8% (-2.5% to 5.7%). For the 10 trials that reported death or disability the pooled odds ratio was 0.90 (0.72 to 1.11). For infections of any type the pooled odds ratio was 0.92 (0.69 to 1.23) and for the seven trials reporting gastrointestinal bleeding it was 1.05 (0.44 to 2.52). With only those trials with the best quality of concealment of allocation, the pooled odds ratio estimates for death and death or disability became closer to unity. Conclusions: This systematic review of randomised controlled trials of corticosteroids in acute traumatic brain injury shows that there remains considerable uncertainty over their effects. Neither moderate benefits nor moderate harmful effects can be excluded. The widely practicable nature of the drugs and the importance of the health problem suggest that large simple trials are feasible and worth while to establish whether there are any benefits from use of corticosteroids in this setting. UK Cochrane Centre, Institute of Child Health, Correspondence to: Dr Alderson.
Prospective study of effect of switching from cigarettes to pipes or cigars on mortality from three smoking related diseasesN J Wald, H C Watt AbstractObjective: To estimate the extent to which cigarette smokers who switch to cigars or pipes alter their risk of dying of three smoking related diseases - lung cancer, ischaemic heart disease, and chronic obstructive lung disease.Design: A prospective study of 21,520 men aged 35-64 years when recruited in 1975-82 with detailed history of smoking and measurement of carboxyhaemoglobin. Main outcome measures: Notification of deaths (to 1993) classified by cause. Results: Pipe and cigar smokers who had switched from
cigarettes over 20 years before entry to the study smoked less tobacco
than cigarette smokers (8.1 g/day v 20 g/day), but
they had the same consumption as pipe and cigar smokers who had never
smoked cigarettes (8.1 g) and had higher carboxyhaemoglobin saturations
(1.2% v 1.0%, P<0.001), indicating that they inhaled
tobacco smoke to a greater extent. They had a 51% higher risk of dying
of the three smoking related diseases than pipe or cigar smokers who
had never smoked cigarettes (relative risk 1.51; 95% confidence
interval 0.96 to 2.38), a 68% higher risk than lifelong non-smokers
(1.68; 1.16 to 2.45), a 57% higher risk than former cigarette smokers
who gave up smoking over 20 years before entry (1.57; 1.04 to 2.38),
and a 46% lower risk than continuing cigarette smokers (0.54; 0.38 to
0.77).
BUPA
Epidemiological Research Group, Correspondence to: Professor Wald.
Prospective cohort study of factors influencing the relative weights of the placenta and the newborn infantLucy A Williams, Sharon F Evans, John P Newnham AbstractObjectives: To determine the demographic, environmental, and medical factors that influence the relative weights of the newborn infant and the placenta and compare this ratio with other factors known to predispose to adult ill health.Design: Prospective cohort study. Setting: The tertiary referral centre for perinatal care in Perth, Western Australia. Subjects: 2,507 pregnant women who delivered a single live infant at term. Main outcome measures: Placental weight, birth weight, and the ratio of placental weight to birth weight. Results: By multiple regression analysis the placental weight to birthweight ratio was significantly and positively associated with gestational age, female sex, Asian parentage, increasing maternal body mass index, increased maternal weight at booking, lower socioeconomic status, maternal anaemia, and increasing number of cigarettes smoked daily. There were no consistent relations between the placental weight to birthweight ratio and measures of newborn size. Conclusions: The ratio of placental weight to birth weight is not an accurate marker of fetal growth. In its role as a predictor of adult disease the ratio may be acting as a surrogate for other factors which are already known to influence health and may act before or after birth. Determining the role that relative growth rates of the fetus and placenta have in predisposing to adult disease requires prospective study to account for the many confounding variables which complicate this hypothesis. Women and Infants Research
Foundation, Correspondence to: Professor Newnham.
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