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RAND Corporation

NonprofitSanta Monica, California, United States
About: RAND Corporation is a nonprofit organization based out in Santa Monica, California, United States. It is known for research contribution in the topics: Population & Health care. The organization has 9602 authors who have published 18570 publications receiving 744658 citations.


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Journal ArticleDOI
05 Jun 2013-JAMA
TL;DR: Current evidence suggests that, when compared with nonsurgical treatments, bariatric surgical procedures in patients with a BMI of 30 to 35 and diabetes are associated with greater short-term weight loss and better intermediate glucose outcomes, and evidence is insufficient to reach conclusions about the appropriate use of bariatric surgery in this population.
Abstract: Importance Bariatric surgery is beneficial in persons with a body mass index (BMI) of 35 or greater with obesity-related comorbidities. There is interest in using these procedures in persons with lower BMI and diabetes. Objective To assess the association between bariatric surgery vs nonsurgical treatments and weight loss and glycemic control among patients with diabetes or impaired glucose tolerance and BMI of 30 to 35. Evidence Review PubMed, EMBASE, and Cochrane Library databases were searched from January 1985 through September 2012. Of 1291 screened articles, we included 32 surgical studies, 11 systematic reviews on nonsurgical treatments, and 11 large nonsurgical studies published after those reviews. Weight loss, metabolic outcomes, and adverse events were abstracted by 2 independent reviewers. Findings Three randomized clinical trials (RCTs) (N = 290; including 1 trial of 150 patients with type 2 diabetes and mean BMI of 37, 1 trial of 80 patients without diabetes [38% with metabolic syndrome] and BMI of 30 to 35, and 1 trial of 60 patients with diabetes and BMI of 30 to 40 [13 patients with BMI 1c levels) during 1 to 2 years of follow-up than nonsurgical treatment. Indirect comparisons of evidence from observational studies of bariatric procedures (n ≈ 600 patients) and meta-analyses of nonsurgical therapies (containing more than 300 RCTs) support this finding at 1 or 2 years of follow-up. However, there are no robust surgical data beyond 5 years of follow-up on outcomes of diabetes, glucose control, or macrovascular and microvascular outcomes. In contrast, some RCT data of nonsurgical therapies show benefits at 10 years of follow-up or more. Surgeon-reported adverse events were low (eg, hospital deaths of 0.3%-1.0%), but data were from select centers and surgeons. Long-term adverse events are unknown. Conclusions and Relevance Current evidence suggests that, when compared with nonsurgical treatments, bariatric surgical procedures in patients with a BMI of 30 to 35 and diabetes are associated with greater short-term weight loss and better intermediate glucose outcomes. Evidence is insufficient to reach conclusions about the appropriate use of bariatric surgery in this population until more data are available about long-term outcomes and complications of surgery.

212 citations

Journal ArticleDOI
TL;DR: Issues of identifying and synthesizing evidence: deciding what type of evidence and outcomes to include in guidelines; integrating values into a guideline; incorporating economic considerations; synthesis, grading, and presentation of evidence; and moving from evidence to recommendations are discussed.
Abstract: Clinical practice guidelines are one of the foundations of efforts to improve healthcare. In 1999, we authored a paper about methods to develop guidelines. Since it was published, the methods of guideline development have progressed both in terms of methods and necessary procedures and the context for guideline development has changed with the emergence of guideline clearinghouses and large scale guideline production organisations (such as the UK National Institute for Health and Clinical Excellence). It therefore seems timely to, in a series of three articles, update and extend our earlier paper. In this second paper, we discuss issues of identifying and synthesizing evidence: deciding what type of evidence and outcomes to include in guidelines; integrating values into a guideline; incorporating economic considerations; synthesis, grading, and presentation of evidence; and moving from evidence to recommendations.

212 citations

Journal ArticleDOI
TL;DR: Findings and recommendations include greater use of theory and logic models, more detailed descriptions of interventions and their implementation, enhanced explanation of desired and unintended outcomes, and better description and measurement of context and of how context influences interventions.
Abstract: Despite a decade's worth of effort, patient safety has improved slowly, in part because of the limited evidence base for the development and widespread dissemination of successful patient safety practices. The Agency for Healthcare Research and Quality sponsored an international group of experts in patient safety and evaluation methods to develop criteria to improve the design, evaluation, and reporting of practice research in patient safety. This article reports the findings and recommendations of this group, which include greater use of theory and logic models, more detailed descriptions of interventions and their implementation, enhanced explanation of desired and unintended outcomes, and better description and measurement of context and of how context influences interventions. Using these criteria and measuring and reporting contexts will improve the science of patient safety.

211 citations

Journal ArticleDOI
10 Feb 1993-JAMA
TL;DR: The rates of inappropriate and uncertain use of coronary artery bypass graft surgery in New York State were very low and did not vary significantly among hospitals, or according to region, volume of bypass operations performed, or teaching status.
Abstract: Objective. —To determine the appropriateness of use of coronary artery bypass graft surgery in New York State. Design. —Retrospective randomized medical record review. Setting. —Fifteen randomly selected hospitals in New York State that provide coronary artery bypass graft surgery. Patients. —Random sample of 1338 patients undergoing isolated coronary artery bypass graft surgery in New York State in 1990. Main Outcome Measures. —Percentage of patients who had bypass surgery for appropriate, inappropriate, or uncertain indications; operative (30-day) mortality; and complications. Results. —Nearly 91% of the bypass operations were rated appropriate; 7%, uncertain; and 2.4%, inappropriate. This low inappropriate rate differs substantially from the 14% rate found in a previous study of patients operated on in 1979,1980, and 1982. The difference in rates was not due to more lenient criteria but to changes in practice, the most important being that the fraction of patients receiving coronary artery bypass grafts for one- and two-vessel disease fell from 51% to 24%. Individual hospital rates of inappropriateness (0% to 5%) did not vary significantly. Rates of appropriateness also did not vary by hospital location, volume, or teaching status. Operative mortality was 2.0%; 17% of patients suffered a complication. Complication rates varied significantly among hospitals (P Conclusions. —The rates of inappropriate and uncertain use of coronary artery bypass graft surgery in New York State were very low. Rates of inappropriate use did not vary significantly among hospitals, or according to region, volume of bypass operations performed, or teaching status. (JAMA. 1993;269:753-760)

211 citations

Journal ArticleDOI
13 Aug 2019-JAMA
TL;DR: In this cohort study conducted between 2000 and 2018 in 6 US metropolitan regions, long-term exposure to ambient air pollutants was significantly associated with increasing emphysema assessed quantitatively using CT imaging and lung function.
Abstract: Importance While air pollutants at historical levels have been associated with cardiovascular and respiratory diseases, it is not known whether exposure to contemporary air pollutant concentrations is associated with progression of emphysema. Objective To assess the longitudinal association of ambient ozone (O3), fine particulate matter (PM2.5), oxides of nitrogen (NOx), and black carbon exposure with change in percent emphysema assessed via computed tomographic (CT) imaging and lung function. Design, Setting, and Participants This cohort study included participants from the Multi-Ethnic Study of Atherosclerosis (MESA) Air and Lung Studies conducted in 6 metropolitan regions of the United States, which included 6814 adults aged 45 to 84 years recruited between July 2000 and August 2002, and an additional 257 participants recruited from February 2005 to May 2007, with follow-up through November 2018. Exposures Residence-specific air pollutant concentrations (O3, PM2.5, NOx, and black carbon) were estimated by validated spatiotemporal models incorporating cohort-specific monitoring, determined from 1999 through the end of follow-up. Main Outcomes and Measures Percent emphysema, defined as the percent of lung pixels less than −950 Hounsfield units, was assessed up to 5 times per participant via cardiac CT scan (2000-2007) and equivalent regions on lung CT scans (2010-2018). Spirometry was performed up to 3 times per participant (2004-2018). Results Among 7071 study participants (mean [range] age at recruitment, 60 [45-84] years; 3330 [47.1%] were men), 5780 were assigned outdoor residential air pollution concentrations in the year of their baseline examination and during the follow-up period and had at least 1 follow-up CT scan, and 2772 had at least 1 follow-up spirometric assessment, over a median of 10 years. Median percent emphysema was 3% at baseline and increased a mean of 0.58 percentage points per 10 years. Mean ambient concentrations of PM2.5and NOx, but not O3, decreased substantially during follow-up. Ambient concentrations of O3, PM2.5, NOx, and black carbon at study baseline were significantly associated with greater increases in percent emphysema per 10 years (O3: 0.13 per 3 parts per billion [95% CI, 0.03-0.24]; PM2.5: 0.11 per 2 μg/m3[95% CI, 0.03-0.19]; NOx: 0.06 per 10 parts per billion [95% CI, 0.01-0.12]; black carbon: 0.10 per 0.2 μg/m3[95% CI, 0.01-0.18]). Ambient O3and NOxconcentrations, but not PM2.5concentrations, during follow-up were also significantly associated with greater increases in percent emphysema. Ambient O3concentrations, but not other pollutants, at baseline and during follow-up were significantly associated with a greater decline in forced expiratory volume in 1 second per 10 years (baseline: 13.41 mL per 3 parts per billion [95% CI, 0.7-26.1]; follow-up: 18.15 mL per 3 parts per billion [95% CI, 1.59-34.71]). Conclusions and Relevance In this cohort study conducted between 2000 and 2018 in 6 US metropolitan regions, long-term exposure to ambient air pollutants was significantly associated with increasing emphysema assessed quantitatively using CT imaging and lung function.

211 citations


Authors

Showing all 9660 results

NameH-indexPapersCitations
Darien Wood1602174136596
Herbert A. Simon157745194597
Ron D. Hays13578182285
Paul G. Shekelle132601101639
John E. Ware121327134031
Linda Darling-Hammond10937459518
Robert H. Brook10557143743
Clifford Y. Ko10451437029
Lotfi A. Zadeh104331148857
Claudio Ronco102131272828
Joseph P. Newhouse10148447711
Kenneth B. Wells10048447479
Moyses Szklo9942847487
Alan M. Zaslavsky9844458335
Graham J. Hutchings9799544270
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202311
202277
2021640
2020574
2019548
2018491