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BACKGROUND Postal and electronic questionnaires are widely used for data collection in epidemiological studies but non-response reduces the effective sample size and can introduce bias. Finding ways to increase response to postal and electronic questionnaires would improve the quality of health research. OBJECTIVES To identify effective strategies to(More)
OBJECTIVE To identify methods to increase response to postal questionnaires. DESIGN Systematic review of randomised controlled trials of any method to influence response to postal questionnaires. STUDIES REVIEWED 292 randomised controlled trials including 258 315 participants INTERVENTION REVIEWED: 75 strategies for influencing response to postal(More)
BACKGROUND Traumatic brain injury (TBI) is a leading cause of death and disability. A reliable prediction of outcome on admission is of great clinical relevance. We aimed to develop prognostic models with readily available traditional and novel predictors. METHODS AND FINDINGS Prospectively collected individual patient data were analyzed from 11 studies.(More)
OBJECTIVE To develop and validate practical prognostic models for death at 14 days and for death or severe disability six months after traumatic brain injury. DESIGN Multivariable logistic regression to select variables that were independently associated with two patient outcomes. Two models designed: "basic" model (demographic and clinical variables(More)
BACKGROUND A commonly reported problem with the conduct of multicentre randomised controlled trials (RCTs) is that recruitment is often slower or more difficult than expected, with many trials failing to reach their planned sample size within the timescale and funding originally envisaged. The aim of this study was to explore factors that may have been(More)
We used Comparative Risk Assessment methods to estimate the health effects of alternative urban land transport scenarios for two settings-London, UK, and Delhi, India. For each setting, we compared a business-as-usual 2030 projection (without policies for reduction of greenhouse gases) with alternative scenarios-lower-carbon-emission motor vehicles,(More)
BACKGROUND Tranexamic acid can reduce bleeding in patients undergoing elective surgery. We assessed the effects of early administration of a short course of tranexamic acid on death, vascular occlusive events, and the receipt of blood transfusion in trauma patients. METHODS This randomised controlled trial was undertaken in 274 hospitals in 40 countries.(More)
OBJECTIVE To examine concordance between treatment effects in animal experiments and clinical trials. Study design Systematic review. DATA SOURCES Medline, Embase, SIGLE, NTIS, Science Citation Index, CAB, BIOSIS. STUDY SELECTION Animal studies for interventions with unambiguous evidence of a treatment effect (benefit or harm) in clinical trials: head(More)
BACKGROUND Smoking cessation programmes delivered via mobile phone text messaging show increases in self-reported quitting in the short term. We assessed the effect of an automated smoking cessation programme delivered via mobile phone text messaging on continuous abstinence, which was biochemically verified at 6 months. METHODS In this single-blind,(More)
OBJECTIVES To identify factors associated with good and poor recruitment to multicentre trials. DATA SOURCES Part A: database of trials started in or after 1994 and were due to end before 2003 held by the Medical Research Council and Health Technology Assessment Programmes. Part B: interviews with people playing a wide range of roles within four trials(More)