Irene Kwan

Increasing response rates to postal questionnaires: systematic review

Abstract 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 questionnaires. Main outcome measure: The proportion of completed or partially completed questionnaires returned. Results: The odds of response were more than doubled when a monetary incentive was used (odds ratio 2.02; 95% confidence interval 1.79 to 2.27) and almost doubled when incentives were not conditional on response (1.71; 1.29 to 2.26). Response was more likely when short questionnaires were used (1.86; 1.55 to 2.24). Personalised questionnaires and letters increased response (1.16; 1.06 to 1.28), as did the use of coloured ink (1.39; 1.16 to 1.67). The odds of response were more than doubled when the questionnaires were sent by recorded delivery (2.21; 1.51 to 3.25) and increased when stamped return envelopes were used (1.26; 1.13 to 1.41) and questionnaires were sent by first class post (1.12; 1.02 to 1.23). Contacting participants before sending questionnaires increased response (1.54; 1.24 to 1.92), as did follow up contact (1.44; 1.22 to 1.70) and providing non-respondents with a second copy of the questionnaire (1.41; 1.02 to 1.94). Questionnaires designed to be of more interest to participants were more likely to be returned (2.44; 1.99 to 3.01), but questionnaires containing questions of a sensitive nature were less likely to be returned (0.92; 0.87 to 0.98). Questionnaires originating from universities were more likely to be returned than were questionnaires from other sources, such as commercial organisations (1.31; 1.11 to 1.54). Conclusions: Health researchers using postal questionnaires can improve the quality of their research by using the strategies shown to be effective in this systematic review. What is already known on this topic Postal questionnaires are widely used in the collection of data in epidemiological studies and health research Non-response to postal questionnaires reduces the effective sample size and can introduce bias What this study adds This systematic review includes more randomised controlled trials than any previously published review or meta-analysis no questionnaire response The review has identified effective ways to increase response to postal questionnaires The review will be updated regularly in the Cochrane Library

Is the normalisation of blood pressure in bleeding trauma patients harmful

Raising of blood pressure can increase tissue perfusion and tissue oxygenation, but the increased pressure might impair the formation of new blood clots or dislodge existing ones. 4 Over the past 50 years several resuscitation strategies have been used to raise the blood pressure in trauma patients until bleeding is controlled. Assessing the evidence for the effectiveness of these approaches has been the aim of a number of systematic reviews by the Cochrane Injuries Group and others. We draw on the results of these reviews to formulate a hypothesis about the management of bleeding trauma patients. Evidence from systematic reviews Medical anti-shock trousers (MAST) provides external pneumatic compression of the legs and was first used in the Vietnam war to stabilise patients with haemorrhagic shock during transportation. After the war, MAST was widely used in the care of bleeding trauma patients. MAST increases blood pressure by compressing blood vessels in the legs thus raising systemic vascular resistance, and by shunting blood from the lower body to the brain, heart, and lungs.

Does animal experimentation inform human healthcare? Observations from a systematic review of international animal experiments on fluid resuscitation

Animal models are often used to test the effectiveness of a drug or procedure before proceeding to clinical trials. One reason for use of animal models is that they allow researchers to focus on particular pathological processes without the confounding effects of other injuries and treatments. However, it is essential that their results are valid and precise. Biased or imprecise results from animal experiments may result in clinical trials of biologically inert or even harmful substances, thus exposing patients to unnecessary risk and wasting scarce research resources. Moreover, if animal experiments fail to inform medical research then the animals suffer unnecessarily. The Italian pathologist Pietro Croce criticised vivisection on scientific grounds. He argued that results from animal experiments cannot be applied to humans because of the biological differences between animals and humans and because the results of animal experiments are too dependent on the type of animal model used.1 Croces arguments were based on insights into zoology and pathophysiology. In this paper, we make some methodological observations on animal experiments. Our observations were made in the context of a systematic review of all available randomised controlled trials of fluid resuscitation in animal models of uncontrolled bleeding. We conducted this review because we wanted to assess the scientific basis for fluid resuscitation. A previous systematic review of randomised trials of fluid resuscitation in bleeding trauma patients had provided no evidence that fluid resuscitation improved outcome.2 #### Summary points New drugs and procedures are usually tested in animals before conducting clinical trials Validity of animal experiments is essential for human health care and fundamental to animal welfare A systematic review of animal experiments on fluid resuscitation found that most studies were underpowered and provided little information on possible bias Systematic reviews of animal experiments allow a more objective appraisal of the evidence and …

Effects of Prehospital Spinal Immobilization: A Systematic Review of Randomized Trials on Healthy Subjects

OBJECTIVE To evaluate the effects of spinal immobilization on healthy participants. METHODS A systematic review of randomized, controlled trials of spinal immobilization on healthy participants. RESULTS Seventeen randomized, controlled trials compared different types of immobilization devices, including collars, backboards, splints, and body strapping. For immobilization efficacy, collars, spine boards, vacuum splints, and abdominal/torso strapping provided a significant reduction in spinal movement. Adverse effects of spinal immobilization included a significant increase in respiratory effort, skin ischemia, pain, and discomfort. CONCLUSIONS Data from this review provide the best available evidence to support the well-recognized efficacy and potential adverse effects of spinal immobilization. However, comparisons of different immobilization strategies on trauma victims must be considered in order to establish an evidence base for this practice.

Identifying controlled evaluation studies of road safety interventions: Searching for needles in a haystack

Problem: Worldwide, over one million people die and about 10 million people sustain permanent disabilities each year in road traffic crashes. It is a matter of urgency that effective strategies, especially from existing controlled trials (CTs), are identified for crash prevention programs. Methods: We used word frequency analysis to develop a search strategy of known sensitivity and positive predictive value (PPV) to identify reports of controlled evaluation studies of road safety interventions in the TRANSPORT database. Results: 23,554 records were searched and 319 (1.4%) records of controlled evaluation studies were identified by handsearching. We were unable to devise search strategies that combined acceptable sensitivity and PPV. Impact on industry: Efforts to improve the identification of CTs of road safety interventions are urgently required. This would involve the documentation of the study design in the title, abstract, and methods section of the research report. The study methodology should be carefully and consistently indexed in road safety databases, and editors can encourage appropriate indexing by insisting on the use of structured abstracts that give details of study methodology.

Recombinant versus urinary gonadotrophin for ovarian stimulation in assisted reproductive technology cycles. A Cochrane review

Several systematic reviews compared recombinant gonadotrophin with urinary gonadotrophins (HMG, purified FSH and highly purified FSH) for ovarian hyperstimulation in IVF and ICSI cycles and these reported conflicting results. Each of these reviews used different inclusion and exclusion criteria for trials. Our aim in producing this review was to bring together all randomized studies in this field under common inclusion criteria with consistent and valid statistical methods.

The development of a register of randomized controlled trials in prehospital trauma care

Objectives. To establish a register of randomized controlled trials of interventions in the prehospital care of trauma patients. Methods. A systematic search was conducted for all randomized controlled trials of interventions in the prehospital care of trauma patients. The search included the Cochrane Controlled Trial Register, the Cochrane Injuries Group Specialised Register, Medline, EMBASE, the Cumulative Index to Nursing & Allied Health Literature (CINAHL), Science Citation Index, National Research Register, Dissertation Abstracts, and PubMed for the time period 1966–2000. There were no language restrictions. In addition, full-text hand searching of a range of relevant journals was done, and the authors of included trials were contacted. Results. The combined search strategy identified 16,037 potentially eligible records, of which 28 were reports of randomized controlled trials evaluating prehospital trauma care interventions. After excluding duplicate reports, there were 24 separate randomized controlled trials including 6,806 patients. The largest and smallest trials involved 1,309 and 30 trauma patients, respectively. Conclusions. This register will facilitate the conduct of systematic reviews of the effectiveness of interventions in prehospital trauma care. However, despite the extensive searching, very few randomized trials in this area were found. In view of the absence of evidence for the effectiveness of many of the interventions that are used in the prehospital care of trauma patients, further randomized controlled trials are required.