Recently Published Projects

Objectives: Objectives: To conduct a systematic review and synthesize evidence for differences in the accuracy of diagnostic tests, and the effects of interventions to prevent and treat Clostridium difficile infection (CDI) in adult patients. Data Sources: Searching for relevant literature was conducted in MEDLINE, the Cochrane Library, and Allied and Complementary Medicine (AMED). ClinicalTrials.gov and expert consultants provided leads to additional studies. We also manually searched reference lists from relevant literature. Review Methods: Standard Evidence-based Practice Center methods were employed. Screening of abstracts and full text articles to identify studies meeting inclusion/exclusion criteria was performed by two independent reviewers. High-quality direct comparison studies were used to examine differences in diagnostic tests. Randomized controlled trials (RCTs) were used to examine comparative effectiveness of antibiotic treatment for CDI. Quality of data extraction was checked by separate reviewers. Quality ratings and strength of evidence grading was performed on included studies. Evidence on diagnostic tests was quantitatively synthesized focusing on differences between test sensitivities and specificities. Evidence on antibiotic treatment was quantitatively examined using pooled analysis. Qualitative narrative analysis was used to synthesize evidence from all available study types for environmental prevention and nonstandard prevention and treatment, with the exception of probiotics as primary prevention, for which a forest plot is provided. Results: Overall, literature was sparse and strength of evidence was generally low due to small sample sizes or lack of adequate controls. For diagnostic testing, direct comparisons of commercially available enzyme immunoassays for C. difficile toxins A and B did not find major differences in sensitivity or specificity. Limited evidence suggests that tests for genes related to the production of C. difficile toxins may be more sensitive than immunoassays for toxins A and B while the comparisons of these test specificities were inconsistent. Moderate evidence in favor of antibiotic restriction policies for prevention was found. Environmental preventive interventions such as glove use and disposable thermometers have limited evidence. However, this literature is largely based on controlling outbreaks. Use of multiple component interventions further limits the ability to synthesize evidence in a meaningful way. Numerous potential new forms of treatment are being examined in placebo controlled RCTs, case series, and case reports. For standard treatment, no antimicrobial is clearly superior for the initial cure of CDI. Recurrence is less frequent with fidaxomicin than with vancomycin. Monoclonal antibodies for prevention and fecal flora reconstitution for multiple recurrences appear promising. Conclusions: Given the frequency and severity of CDI and the fact that future reimbursement policy may withhold payment for hospital-acquired infections, this is an under-researched topic. More precise estimates of the magnitude of differences in test sensitivities and specificities are needed. More importantly, studies have not established that any of the possible differences in test accuracy would lead to substantially different patient outcomes in clinical practice. More research on effective treatment and unintended consequences of treatment, such as resistance, is needed. Gut flora may be important, but improved understanding of healthy gut ecology and the complex interactions is necessary before continuing to pursue probiotics.

Objectives: Objectives: To update a 2007 systematic review on the effectiveness and safety of treatments to prevent fractures in persons with low bone density or osteoporosis and factors affecting adherence to these treatments, and to assess whether monitoring helps identify those most likely to benefit from treatment and the benefits of long-term treatment. Data Sources: MEDLINE®, Embase, the Cochrane Database of Systematic Reviews, and Clinical Trials.gov were searched from January 2005 through March 2011. Review Methods: After review by two investigators against predetermined inclusion/exclusion criteria, we included existing systematic reviews, randomized controlled clinical trials, and large observational studies, where appropriate, for assessment of treatment efficacy, safety, and adherence. Results: Alendronate, risedronate, zoledronic acid, denosumab, and teriparatide reduce the risk of vertebral and nonvertebral fractures among postmenopausal women with osteoporosis. Ibandronate and raloxifene reduce the risk of vertebral but not nonvertebral fractures. Alendronate, risedronate, zoledronic acid, and denosumab prevent hip fractures among postmenopausal women with osteoporosis. Risedronate decreases the risk of vertebral and nonvertebral fracture among men with osteoporosis. Among those treated with glucocorticoids, fracture risk reduction was demonstrated for risedronate and alendronate compared to placebo; and for teriparatide compared to alendronate. Few studies have compared osteoporosis therapies head-to-head. Adherence to pharmacotherapy is poor in patients with osteoporosis, as with other chronic conditions. Many factors affect adherence to medications, including dosing frequency, side effects of medications, knowledge about osteoporosis, and cost. Age, prior history of fracture, and concomitant medication use do not appear to have an independent association with adherence. Dosing frequency appears to affect adherence: Adherence is improved with weekly compared to daily regimens, but evidence is lacking to show that monthly regimens improve adherence over that of weekly regimens. Decreased adherence to bisphosphonates is associated with less than optimal reduction in the risk of fracture. Insufficient evidence is available to make conclusions about how adherence to and persistence with newer osteoporosis therapies compare to that with bisphosphonates. Assessment of adverse effects finds that raloxifene is associated with an increased risk for pulmonary embolism and vasomotor flushing; and limited data support a possible association between bisphosphonate use and atypical subtrochanteric fractures of the femur. Evidence is limited on the utility of monitoring and long-term treatment. Conclusions: There is a high level of evidence that shows that fracture risk reduction is greatest in women with a diagnosis of osteoporosis and/or prevalent fractures. The level of evidence is low to moderate for fracture risk reduction in postmenopausal women with osteopenia and without prevalent fractures. The evidence is low for benefits of treatment for other populations, including men; for the benefits and risks of long-term treatment; and for the need (if any) for monitoring bone density; and mixed with regard to factors that influence adherence.

Objectives: Objectives: Systematic review of outcomes of three treatments for osteoarthritis (OA) of the knee: intra-articular viscosupplementation; oral glucosamine, chondroitin or the combination; and arthroscopic lavage or debridement. Data Sources: We abstracted data from: 42 randomized, controlled trials (RCTs) of viscosupplementation, all but one synthesized among six meta-analyses; 21 RCTs of glucosamine/chondroitin, 16 synthesized among 6 meta-analyses; and 23 articles on arthroscopy. The search included foreign-language studies and relevant conference proceedings. Review Methods: The review methods were defined prospectively in a written protocol. We sought systematic reviews, meta-analyses, and RCTs published in full or in abstract. Where randomized trials were few, we sought other study designs. We independently assessed the quality of all primary studies. Results: Viscosupplementation trials generally report positive effects on pain and function scores compared to placebo, but the evidence on clinical benefit is uncertain, due to variable trial quality, potential publication bias, and unclear clinical significance of the changes reported. The Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT), a large (n=1,583), high- quality, National Institutes of Health-funded, multicenter RCT showed no significant difference compared to placebo. Glucosamine sulfate has been reported to be more effective than glucosamine hydrochloride, which was used in GAIT, but the evidence is not sufficient to draw conclusions. Clinical studies of glucosamine effect on glucose metabolism are short term, or if longer (e.g., 3 years), excluded patients with metabolic disorders. The best available evidence for arthroscopy, a single sham-controlled RCT (n=180), showed that arthroscopic lavage with or without debridement was equivalent to placebo. The main limitations of this trial are the use of a single surgeon and enrollment of patients at a single Veterans Affairs Medical Center. No studies reported separately on patients with secondary OA of the knee. The only comparative study was an underpowered, poor-quality trial comparing viscosupplementation to arthroscopy with debridement. Conclusions: Osteoarthritis of the knee is a common condition. The three interventions reviewed in this report are widely used in the treatment of OA of the knee, yet the best available evidence does not clearly demonstrate clinical benefit. Uncertainty regarding clinical benefit can be resolved only by rigorous, multicenter RCTs. In addition, given the public health impact of OA of the knee, research on new approaches to prevention and treatment should be given high priority.

Objectives: Systematic review of imaging tests for diagnosis, staging, and/or screening of pancreatic adenocarcinoma

Objectives: Background: Depressive disorders such as major depressive disorder (MDD), dysthymia, and subsyndromal depression may be serious disabling illnesses. MDD affects more than 16 percent of adults at some point during their lifetimes. Second-generation antidepressants dominate the medical management of depressive disorders. These drugs include selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), and other drugs with related mechanisms of action that selectively target neurotransmitters. Objectives: The objective of this report was to compare the benefits and harms of bupropion, citalopram, desvenlafaxine, duloxetine, escitalopram, fluoxetine, fluvoxamine, mirtazapine, nefazodone, paroxetine, sertraline, trazodone, and venlafaxine for the treatment of depressive disorders, including variations of effects in patients with accompanying symptoms and patient subgroups. Data Sources: We updated a comparative effectiveness review published in 2007 by the Agency for Healthcare Research and Quality searching PubMed, Embase, The Cochrane Library, and International Pharmaceutical Abstracts up to January 2011. Review Methods: Two people independently reviewed the literature, abstracted data, and rated the risk of bias. If data were sufficient, we conducted meta-analyses of head-to-head trials of the relative benefit of response to treatment. In addition, we conducted mixed treatment comparisons to derive indirect estimates of the comparative efficacy among all second-generation antidepressants. Results: From a total of 3,722 citations, we identified 248 studies of good or fair quality. Overall, no substantial differences in efficacy could be detected among second-generation antidepressants for the treatment of acute-phase MDD. Statistically significant differences in response rates between some drugs are small and likely not clinically relevant. No differences in efficacy were apparent in patients with accompanying symptoms or in subgroups based on age, sex, ethnicity, or comorbidities, although evidence within these subpopulations was limited. Differences exist in the incidence of specific adverse events and the onset of action. Venlafaxine leads to higher rates of nausea and vomiting, sertraline to higher rates of diarrhea, and mirtazapine to higher rates of weight gain than comparator drugs. Bupropion causes lower rates of sexual dysfunction than other antidepressants. The evidence is insufficient to draw conclusions about the comparative efficacy and effectiveness for the treatment of dysthymia and subsyndromal depression. Conclusions: Our findings indicate that the existing evidence does not warrant the choice of one second-generation antidepressant over another based on greater efficacy and effectiveness. Differences with respect to onset of action and adverse events may be taken into consideration for the choice of a medication.