Statistical methodologies to pool across multiple intervention studies

Combining and analyzing data from heterogeneous randomized controlled trials of complex multiple-component intervention studies, or discussing them in a systematic review, is not straightforward. The present article describes certain issues to be considered when combining data across studies, based on discussions in an NIH-sponsored workshop on pooling issues across studies in consortia (see Belle et al. in Psychol Aging, 18(3):396–405, 2003). Several statistical methodologies are described and their advantages and limitations are explored. Whether weighting the different studies data differently, or via employing random effects, one must recognize that different pooling methodologies may yield different results. Pooling can be used for comprehensive exploratory analyses of data from RCTs and should not be viewed as replacing the standard analysis plan for each study. Pooling may help to identify intervention components that may be more effective especially for subsets of participants with certain behavioral characteristics. Pooling, when supported by statistical tests, can allow exploratory investigation of potential hypotheses and for the design of future interventions

Building an international network for a primary care research program: reflections on challenges and solutions in the set-up and delivery of a prospective observational study of acute cough in 13 European countries

BACKGROUND: Implementing a primary care clinical research study in several countries can make it possible to recruit sufficient patients in a short period of time that allows important clinical questions to be answered. Large multi-country studies in primary care are unusual and are typically associated with challenges requiring innovative solutions. We conducted a multi-country study and through this paper, we share reflections on the challenges we faced and some of the solutions we developed with a special focus on the study set up, structure and development of Primary Care Networks (PCNs).METHOD: GRACE-01 was a multi-European country, investigator-driven prospective observational study implemented by 14 Primary Care Networks (PCNs) within 13 European Countries. General Practitioners (GPs) recruited consecutive patients with an acute cough. GPs completed a case report form (CRF) and the patient completed a daily symptom diary. After study completion, the coordinating team discussed the phases of the study and identified challenges and solutions that they considered might be interesting and helpful to researchers setting up a comparable study.RESULTS: The main challenges fell within three domains as follows:i) selecting, setting up and maintaining PCNs;ii) designing local context-appropriate data collection tools and efficient data management systems; andiii) gaining commitment and trust from all involved and maintaining enthusiasm.The main solutions for each domain were:i) appointing key individuals (National Network Facilitator and Coordinator) with clearly defined tasks, involving PCNs early in the development of study materials and procedures.ii) rigorous back translations of all study materials and the use of information systems to closely monitor each PCNs progress;iii) providing strong central leadership with high level commitment to the value of the study, frequent multi-method communication, establishing a coherent ethos, celebrating achievements, incorporating social events and prizes within meetings, and providing a framework for exploitation of local data.CONCLUSIONS: Many challenges associated with multi-country primary care research can be overcome by engendering strong, effective communication, commitment and involvement of all local researchers. The practical solutions identified and the lessons learned in implementing the GRACE-01 study may assist in establishing other international primary care clinical research platforms

Incidence, patterns and severity of reported unintentional injuries in Pakistan for persons five years and older: results of the National Health Survey of Pakistan 1990–94

<p>Abstract</p> <p>Background</p> <p>National level estimates of injuries are not readily available for developing countries. This study estimated the annual incidence, patterns and severity of unintentional injuries among persons over five years of age in Pakistan.</p> <p>Methods</p> <p>National Health Survey of Pakistan (NHSP 1990–94) is a nationally representative survey of the household. Through a two-stage stratified design, 18, 315 persons over 5 years of age were interviewed to estimate the overall annual incidence, patterns and severity of unintentional injuries for males and females in urban and rural areas over the preceding one year. Weighted estimates were computed adjusting for complex survey design using <it>surveyfreq </it>and <it>surveylogistic </it>option of SAS 9.1 software.</p> <p>Results</p> <p>The overall annual incidence of all unintentional injuries was 45.9 (CI: 39.3–52.5) per 1000 per year; 59.2 (CI: 49.2–69.2) and 33.2 (CI: 27.0–39.4) per 1000 per year among males and females over five years of age, respectively. An estimated 6.16 million unintentional injuries occur in Pakistan annually among persons over five years of age. Urban and rural injuries were 55.9 (95% CI: 48.1–63.7) and 41.2 (95% CI: 32.2–50.0) per 1000 per year, respectively. The annual incidence of injuries due to falls were 22.2 (95% CI: 18.0–26.4), poisoning 3.3 (95%CI: 0.5–6.1) and burn was 1.5 (95%CI: 0.9–2.1) per 1000 per year. The majority of injuries occurred at home 19.2 (95%CI: 16.0–22.4) or on the roads 17.0 (95%CI: 13.8–20.2). Road traffic/street, school and urban injuries were more likely to result in handicap.</p> <p>Conclusion</p> <p>There is high burden of unintentional injuries among persons over five years of age in Pakistan. These results are useful to plan further studies and prioritizing prevention programs on injuries nationally and other developing countries with similar situation.</p

Intimate partner violence: a study in men and women from six European countries

OBJECTIVES: We aimed to assess intimate partner violence (IPV) among men and women from six cities in six European countries. METHODS: Four IPV types were measured in a population-based multicentre study of adults (18-64 years; n = 3,496). Sex- and city-differences in past year prevalence were examined considering victims, perpetrators or both and considering violent acts' severity and repetition. RESULTS: Male victimization of psychological aggression ranged from 48.8 % (Porto) to 71.8 % (Athens) and female victimization from 46.4 % (Budapest) to 70.5 % (Athens). Male and female victimization of sexual coercion ranged from 5.4 and 8.9 %, respectively, in Budapest to 27.1 and 25.3 % in Stuttgart. Male and female victims of physical assault ranged from 9.7 and 8.5 %, respectively, in Porto, to 31.2 and 23.1 % in Athens. Male victims of injury were 2.7 % in Östersund and 6.3 % in London and female victims were 1.4 % in Östersund and 8.5 % in Stuttgart. IPV differed significantly across cities (p < 0.05). Men and women predominantly experienced IPV as both victims and perpetrators with few significant sex-differences within cities. CONCLUSIONS: Results support the need to consider men and women as both potential victims and perpetrators when approaching IPV

Effect of enalapril on 12-year survival and life expectancy in patients with left ventricular systolic dysfunction: a follow-up study

Background In the studies of left ventricular dysfunction (SOLVD), enalapril reduced mortality in patients with symptomatic but not asymptomatic left ventricular systolic dysfunction during the trial. We did a 12-year follow-up of SOLVD to establish if the mortality reduction with enalapril among patients with heart failure was sustained, and whether a subsequent reduction in mortality would emerge among those with asymptomatic ventricular dysfunction. Methods Of the 6797 patients previously enrolled in the SOLVD prevention and treatment trials, we ascertained the subsequent vital status of 5165 individuals who were alive when the trials had been completed. Follow-up was done through direct contacts in Belgium and linkages with national death registries and federal beneficiary or historic tax summary files in the USA and Canada. Findings Follow-up was 99.8% (6784/6797) complete. In the prevention trial, 50.9% (1074/2111) of the enalapril group had died compared with 56.4% (1195/2117) of the placebo group (generalised Wilcoxon p=0.001). In the treatment trial, 79.8% (1025/1285) of the enalapril group had died compared with 80.8% (1038/1284) of the placebo group (generalised Wilcoxon p=0.01). The reductions in cardiac deaths were significant and similar in both trials. When data for the prevention and treatment trials were combined, the hazard ratio for death was 0.90 for the enalapril group compared with the placebo group (95% Cl 0.84-0.95, generalised Wilcoxon p=0.0003). Enalapril extended median survival by 9.4 months in the combined trials (95% CI 2.8-16.5, p=0.004). Interpretation Treatment with enalapril for 3-4 years led to a sustained improvement in survival beyond the original trial period in patients with left ventricular systolic dysfunction, with an important increase in life expectancy