Pittas A.G.,Tufts Medical Center |
Chung M.,Tufts Evidence based Practice Center |
Trikalinos T.,Tufts Evidence based Practice Center |
Mitri J.,Tufts Medical Center |
And 5 more authors.
Annals of Internal Medicine | Year: 2010
Background: Vitamin D may modify risk for cardiometabolic outcomes (type 2 diabetes, hypertension, or cardiovascular disease). Purpose: To examine the association between vitamin D status, including the effect of vitamin D supplementation, and cardiometabolic outcomes in generally healthy adults. Data Sources: English-language studies in MEDLINE (inception to 4 November 2009) and the Cochrane Central Register of Controlled Trials (fourth quarter of 2009). Study Selection: 11 reviewers screened citations to identify longitudinal cohort studies that reported associations between vitamin D status and cardiometabolic outcomes, including randomized trials of vitamin D supplementation. Data Extraction: 5 independent reviewers extracted data about study conduct, participant characteristics, outcomes, and quality. Differences were resolved by consensus. Data Synthesis: 13 observational studies (14 cohorts) and 18 trials were eligible. Three of 6 analyses (from 4 different cohorts) reported a lower incident diabetes risk in the highest versus the lowest vitamin D status groups. Eight trials found no effect of vitamin D supplementation on glycemia or incident diabetes. In meta-analysis of 3 cohorts, lower 25-hydroxyvitamin D concentration was associated with incident hypertension (relative risk, 1.8 [95% CI, 1.3 to 2.4]). In meta-analyses of 10 trials, supplementation nonsignificantly reduced systolic blood pressure (weighted mean difference, -1.9 mm Hg [CI, -4.2 to 0.4 mm Hg]) and did not affect diastolic blood pressure (weighted mean difference, -0.1 mm Hg [CI, -0.7 to 0.5 mm Hg]). Lower 25-hydroxyvitamin D concentration was associated with incident cardiovascular disease in 5 of 7 analyses (6 cohorts). Four trials found no effect of supplementation on cardiovascular outcomes. Limitations: Studies included primarily white participants. Observational studies were heterogeneous. Several trials reported post hoc analyses. Conclusion: The association between vitamin D status and cardiometabolic outcomes is uncertain. Trials showed no clinically significant effect of vitamin D supplementation at the dosages given. Primary Funding Source: National Institute of Diabetes and Digestive and Kidney Disease, the National Institutes of Health Office of Dietary Supplements, U.S. Food and Drug Administration, Agency for Healthcare Research and Quality, and Public Health Agency of Canada. © 2010 American College of Physicians.
PubMed | Tufts Evidence based Practice Center
Type: | Journal: Systematic reviews | Year: 2012
Systematic reviews have become increasingly critical to informing healthcare policy; however, they remain a time-consuming and labor-intensive activity. The extraction of data from constituent studies comprises a significant portion of this effort, an activity which is often needlessly duplicated, such as when attempting to update a previously conducted review or in reviews of overlapping topics.In order to address these inefficiencies, and to improve the speed and quality of healthcare policy- and decision-making, we have initiated the development of the Systematic Review Data Repository, an open collaborative Web-based repository of systematic review data. As envisioned, this resource would serve as both a central archive and data extraction tool, shared among and freely accessible to organizations producing systematic reviews worldwide. A suite of easy-to-use software tools with a Web frontend would enable researchers to seamlessly search for and incorporate previously deposited data into their own reviews, as well as contribute their own.In developing this resource, we identified a number of technical and non-technical challenges, as well as devised a number of potential solutions, including proposals for systems and software tools to assure data quality, stratify and control user access effectively and flexibly accommodate all manner of study data, as well as means by which to govern and foster adoption of this new resource.Herein we provide an account of the rationale and development of the Systematic Review Data Repository thus far, as well as outline its future trajectory.
PubMed | Tufts Evidence Based Practice Center
Type: Journal Article | Journal: JAMA otolaryngology-- head & neck surgery | Year: 2013
Sensorineural hearing loss is the third leading cause of years lived with disability worldwide. Cochlear implants may provide a viable alternative to hearing aids for this type of hearing loss. The Coverage and Analysis Group at the Centers for Medicare & Medicaid Services was interested in an evaluation of recently published literature on this topic. In addition, this meta-analysis is to our knowledge the first to evaluate quality-of-life (QOL) outcomes in adults with cochlear implants.To evaluate the communication-related outcomes and health-related QOL outcomes after unilateral or bilateral cochlear implantation in adults with sensorineural hearing loss.MEDLINE, Cochrane Central Register of Controlled Trials, Scopus, and previous reports from January 1, 2004, through May 31, 2012.Published studies of adult patients undergoing unilateral or bilateral procedures with multichannel cochlear implants and assessments using open-set sentence tests, multisyllable word tests, or QOL measures.Five researchers extracted information on population characteristics, outcomes of interest, and study design and assessed the studies for risk of bias. Discrepancies were resolved by consensus.A total of 42 studies met the inclusion criteria. Most unilateral implant studies showed a statistically significant improvement in mean speech scores as measured by open-set sentence or multisyllable word tests; meta-analysis revealed a significant improvement in QOL after unilateral implantation. Results from studies assessing bilateral implantation showed improvement in communication-related outcomes compared with unilateral implantation and additional improvements in sound localization compared with unilateral device use or implantation only. Based on a few studies, the QOL outcomes varied across tests after bilateral implantation.Unilateral cochlear implants provide improved hearing and significantly improve QOL, and improvements in sound localization are noted for bilateral implantation. Future studies of longer duration, higher-quality reporting, and large databases or registries of patients with long-term follow-up data are needed to yield stronger evidence.