Vandana Sundaram

Diagnosing and Managing Common Food Allergies: A Systematic Review

CONTEXT There is heightened interest in food allergies but no clear consensus exists regarding the prevalence or most effective diagnostic and management approaches to food allergies. OBJECTIVE To perform a systematic review of the available evidence on the prevalence, diagnosis, management, and prevention of food allergies. DATA SOURCES Electronic searches of PubMed, Cochrane Database of Systematic Reviews, Cochrane Database of Abstracts of Reviews of Effects, and Cochrane Central Register of Controlled Trials. Searches were limited to English-language articles indexed between January 1988 and September 2009. STUDY SELECTION Diagnostic tests were included if they had a prospective, defined study population, used food challenge as a criterion standard, and reported sufficient data to calculate sensitivity and specificity. Systematic reviews and randomized controlled trials (RCTs) for management and prevention outcomes were also used. For foods where anaphylaxis is common, cohort studies with a sample size of more than 100 participants were included. DATA EXTRACTION Two investigators independently reviewed all titles and abstracts to identify potentially relevant articles and resolved discrepancies by repeated review and discussion. Quality of systematic reviews and meta-analyses was assessed using the AMSTAR criteria, the quality of diagnostic studies using the QUADAS criteria most relevant to food allergy, and the quality of RCTs using the Jadad criteria. DATA SYNTHESIS A total of 12,378 citations were identified and 72 citations were included. Food allergy affects more than 1% to 2% but less than 10% of the population. It is unclear if the prevalence of food allergies is increasing. Summary receiver operating characteristic curves comparing skin prick tests (area under the curve [AUC], 0.87; 95% confidence interval [CI], 0.81-0.93) and serum food-specific IgE (AUC, 0.84; 95% CI, 0.78-0.91) to food challenge showed no statistical superiority for either test. Elimination diets are the mainstay of therapy but have been rarely studied. Immunotherapy is promising but data are insufficient to recommend use. In high-risk infants, hydrolyzed formulas may prevent cows milk allergy but standardized definitions of high risk and hydrolyzed formula do not exist. CONCLUSION The evidence for the prevalence and management of food allergy is greatly limited by a lack of uniformity for criteria for making a diagnosis.

Systematic Review: The Comparative Effectiveness of Percutaneous Coronary Interventions and Coronary Artery Bypass Graft Surgery

Context The relative benefits and harms of coronary artery bypass graft surgery (CABG) versus percutaneous coronary intervention (PCI) are sometimes unclear. Contribution This systematic review of 23 randomized trials found that survival at 10 years was similar for CABG and PCI, even among diabetic patients. Procedural strokes and angina relief were more common after CABG (risk difference, 0.6% and about 5% to 8%, respectively), whereas repeated revascularization procedures were more common after PCI (risk difference, 24% at 1 year). Caution Only 1 small trial used drug-eluting stents. Few patients with extensive coronary disease or poor ventricular function were enrolled. The Editors Coronary artery bypass graft (CABG) surgery and catheter-based percutaneous coronary intervention (PCI), with or without coronary stents, are alternative approaches to mechanical coronary revascularization. These 2 coronary revascularization techniques are among the most common major medical procedures performed in North America and Europe: In 2005, 261000 CABG procedures and 645000 PCI procedures were performed in the United States alone (1). However, the comparative effectiveness of CABG and PCI remains poorly understood for patients in whom both procedures are technically feasible and coronary revascularization is clinically indicated. In patients with left main or triple-vessel coronary artery disease with reduced left ventricular function, CABG is generally preferred because randomized, controlled trials (RCTs) have shown that it improves survival compared with medical therapy (2, 3). In patients with most forms of single-vessel disease, PCI is generally the preferred form of coronary revascularization (4), in light of its lower clinical risk and the evidence that PCI reduces angina and myocardial ischemia in this subset of patients (5). Most RCTs comparing CABG and PCI have been conducted in populations with coronary artery disease between these extremes, namely patients with single-vessel, proximal left anterior descending disease; most forms of double-vessel disease; or less extensive forms of triple-vessel disease. We sought to evaluate the evidence from RCTs on the comparative effectiveness of PCI and CABG. We included trials using balloon angioplasty or coronary stents because quantitative reviews have shown no differences in mortality or myocardial infarction between these PCI techniques (6, 7). We also included trials using standard or minimally invasive CABG or both procedures (8, 9). We sought to document differences between PCI and CABG in survival, cardiovascular complications (such as stroke and myocardial infarction), and freedom from angina. Finally, we reviewed selected observational studies to assess the generalizability of the RCTs. Methods Data Sources We searched the MEDLINE, EMBASE, and Cochrane databases for studies published between January 1966 and August 2006 by using such terms as angioplasty, coronary, and coronary artery bypass surgery, as reported in detail elsewhere (10). We also sought additional studies by reviewing the reference lists of included articles, conference abstracts, and the bibliographies of expert advisors. We did not limit the searches to the English language. Study Selection We sought RCTs that compared health outcomes of PCI and CABG. We excluded trials that compared PCI alone or CABG alone with medical therapy, those that compared 2 forms of PCI, and those that compared 2 forms of CABG. The outcomes of interest were survival, myocardial infarction, stroke, angina, and use of additional revascularization procedures. Two investigators independently reviewed titles, abstracts, and the full text as needed to determine whether studies met inclusion criteria. Conflicts between reviewers were resolved through re-review and discussion. We did not include results published solely in abstract form. Data Extraction and Quality Assessment Two authors independently abstracted data on study design; setting; population characteristics (sex, age, race/ethnicity, comorbid conditions, and coronary anatomy); eligibility and exclusion criteria; procedures performed; numbers of patients screened, eligible, enrolled, and lost to follow-up; method of outcome assessment; and results for each outcome. We assessed the quality of included trials by using predefined criteria and graded their quality as A, B, or C by using methods described in detail elsewhere (10). In brief, a grade of A indicates a high-quality trial that clearly described the population, setting, interventions, and comparison groups; randomly allocated patients to alternative treatments; had low dropout rates; and reported intention-to-treat analysis of outcomes. A grade of B indicates a randomized trial with incomplete information about methods that might mask important limitations. A grade of C indicates that the trial had evident flaws, such as improper randomization, that could introduce significant bias. Data Synthesis and Analysis We used random-effects models to compute weighted mean rates and SEs for each outcome. We computed summary risk differences and odds ratios between PCI and CABG and the 95% CI for each outcome of interest at annual intervals. Because the results did not differ materially when risk differences and odds ratios (10) were used and the low rate of several outcomes (for example, procedural mortality) made the risk difference a more stable outcome metric (11, 12), we report here only the risk differences. We assessed heterogeneity of effects by using chi-square and I 2 statistics (13). When effects were heterogeneous (I 2 > 50%), we explored the effects of individual studies on summary effects by removing each study individually. We assessed the possibility of publication bias by visual inspection of funnel plots and calculated the number of missing studies required to change a statistically significant summary effect to not statistically significant (11). We performed analyses by using Comprehensive Meta-Analysis software, version 2.0 (Biostat, Englewood, New Jersey). Inclusion of Observational Studies We also searched for observational data to evaluate the generalizability of the RCT results, as reported in detail elsewhere (10). In brief, we included observational studies from clinical or administrative databases that included at least 1000 recipients of each revascularization procedure and provided sufficient information about the patient populations (such as demographic characteristics, preprocedure coronary anatomy, and comorbid conditions) and procedures performed (such as balloon angioplasty vs. bare-metal stents vs. drug-eluting stents). Role of the Funding Source This project was supported by the Agency for Healthcare Research and Quality. Representatives of the funding agency reviewed and commented on the study protocol and drafts of the manuscript, but the authors had final responsibility for the design, conduct, analysis, and reporting of the study. Results We identified 1695 potentially relevant articles, of which 204 merited full-text review (Appendix Figure). A total of 113 articles reporting on 23 unique RCTs met inclusion criteria (Table 1 [14126]). These trials enrolled a total of 9963 patients, of whom 5019 were randomly assigned to PCI and 4944 to CABG. Most trials were conducted in Europe, the United Kingdom, or both locations; only 3 trials were performed in the United States. The early studies (patient entry from 1987 to 1993) used balloon angioplasty as the PCI technique, and the later studies (patient entry from 1994 to 2002) used stents as the PCI technique. Only 1 small trial of PCI versus CABG used drug-eluting stents (116). Nine trials limited entry to patients with single-vessel disease of the proximal left anterior descending artery, whereas the remaining 14 trials enrolled patients with multivessel disease, either predominantly (3 trials) or exclusively (11 trials). Appendix Figure. Study flow diagram. CABG= coronary artery bypass grafting; CAD= coronary artery disease; PCI= percutaneous coronary intervention; RCT= randomized, controlled trial. Table 1. Overview of Randomized, Controlled Trials The quality of 21 trials was graded as A, and 1 trial (117) was graded as B. One trial (116) was graded as C because randomization may not have been properly executed (details are available elsewhere [10]). We performed sensitivity analyses by removing these studies from the analysis, and our summary results did not change statistically significantly. The average age of the trial participants was 61 years, 27% were women, and most were of European ancestry. Roughly 20% had diabetes, half had hypertension, and half had hyperlipidemia. Whereas approximately 40% of patients had a previous myocardial infarction, few had heart failure or poor left ventricular function. Among studies that enrolled patients with multivessel coronary disease, most had double-vessel rather than triple-vessel disease. Revascularization procedures were performed by using standard methods for the time the trial was conducted (Table 1). Among patients with multivessel disease, more grafts were placed during CABG than vessels were dilated during PCI. Among patients assigned to PCI, stents were commonly used in the recent studies, but in the earlier trials, balloon angioplasty was standard. Among patients assigned to CABG, arterial grafting with the left internal mammary artery was frequently done, especially in more recent trials. Some studies used minimally invasive, direct coronary artery bypass and off-pump operations to perform CABG in patients with single-vessel left anterior descending disease (Table 1). Short-Term and Procedural Outcomes Survival (within 30 days of the procedure) was high for both procedures: 98.9% for PCI and 98.2% for CABG. When data from all trials were combined, the survival difference between PCI and CABG was small and not statistically significant (0.2% [95% CI, 0.3% to 0.6%]) (Figure 1

Are Organic Foods Safer or Healthier Than Conventional Alternatives?: A Systematic Review

BACKGROUND The health benefits of organic foods are unclear. PURPOSE To review evidence comparing the health effects of organic and conventional foods. DATA SOURCES MEDLINE (January 1966 to May 2011), EMBASE, CAB Direct, Agricola, TOXNET, Cochrane Library (January 1966 to May 2009), and bibliographies of retrieved articles. STUDY SELECTION English-language reports of comparisons of organically and conventionally grown food or of populations consuming these foods. DATA EXTRACTION 2 independent investigators extracted data on methods, health outcomes, and nutrient and contaminant levels. DATA SYNTHESIS 17 studies in humans and 223 studies of nutrient and contaminant levels in foods met inclusion criteria. Only 3 of the human studies examined clinical outcomes, finding no significant differences between populations by food type for allergic outcomes (eczema, wheeze, atopic sensitization) or symptomatic Campylobacter infection. Two studies reported significantly lower urinary pesticide levels among children consuming organic versus conventional diets, but studies of biomarker and nutrient levels in serum, urine, breast milk, and semen in adults did not identify clinically meaningful differences. All estimates of differences in nutrient and contaminant levels in foods were highly heterogeneous except for the estimate for phosphorus; phosphorus levels were significantly higher than in conventional produce, although this difference is not clinically significant. The risk for contamination with detectable pesticide residues was lower among organic than conventional produce (risk difference, 30% [CI, -37% to -23%]), but differences in risk for exceeding maximum allowed limits were small. Escherichia coli contamination risk did not differ between organic and conventional produce. Bacterial contamination of retail chicken and pork was common but unrelated to farming method. However, the risk for isolating bacteria resistant to 3 or more antibiotics was higher in conventional than in organic chicken and pork (risk difference, 33% [CI, 21% to 45%]). LIMITATION Studies were heterogeneous and limited in number, and publication bias may be present. CONCLUSION The published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods. Consumption of organic foods may reduce exposure to pesticide residues and antibiotic-resistant bacteria. PRIMARY FUNDING SOURCE None.

Quality improvement strategies for hypertension management: a systematic review.

Background:Care remains suboptimal for many patients with hypertension. Purpose:The purpose of this study was to assess the effectiveness of quality improvement (QI) strategies in lowering blood pressure. Data Sources:MEDLINE, Cochrane databases, and article bibliographies were searched for this study. Study Selection:Trials, controlled before–after studies, and interrupted time series evaluating QI interventions targeting hypertension control and reporting blood pressure outcomes were studied. Data Extraction:Two reviewers abstracted data and classified QI strategies into categories: provider education, provider reminders, facilitated relay of clinical information, patient education, self-management, patient reminders, audit and feedback, team change, or financial incentives were extracted. Data Synthesis:Forty-four articles reporting 57 comparisons underwent quantitative analysis. Patients in the intervention groups experienced median reductions in systolic blood pressure (SBP) and diastolic blood pressure (DBP) that were 4.5 mm Hg (interquartile range [IQR]: 1.5 to 11.0) and 2.1 mm Hg (IQR: −0.2 to 5.0) greater than observed for control patients. Median increases in the percentage of individuals achieving target goals for SBP and DBP were 16.2% (IQR: 10.3 to 32.2) and 6.0% (IQR: 1.5 to 17.5). Interventions that included team change as a QI strategy were associated with the largest reductions in blood pressure outcomes. All team change studies included assignment of some responsibilities to a health professional other than the patients physician. Limitations:Not all QI strategies have been assessed equally, which limits the power to compare differences in effects between strategies. Conclusion:QI strategies are associated with improved hypertension control. A focus on hypertension by someone in addition to the patients physician was associated with substantial improvement. Future research should examine the contributions of individual QI strategies and their relative costs.

Systematic Review: Benefits and Harms of In-Hospital Use of Recombinant Factor VIIa for Off-Label Indications

BACKGROUND Recombinant factor VIIa (rFVIIa), a hemostatic agent approved for hemophilia, is increasingly used for off-label indications. PURPOSE To evaluate the benefits and harms of rFVIIa use for 5 off-label, in-hospital indications: intracranial hemorrhage, cardiac surgery, trauma, liver transplantation, and prostatectomy. DATA SOURCES Ten databases (including PubMed, EMBASE, and the Cochrane Library) queried from inception through December 2010. Articles published in English were analyzed. STUDY SELECTION Two reviewers independently screened titles and abstracts to identify clinical use of rFVIIa for the selected indications and identified all randomized, controlled trials (RCTs) and observational studies for full-text review. DATA EXTRACTION Two reviewers independently assessed study characteristics and rated study quality and indication-wide strength of evidence. DATA SYNTHESIS 16 RCTs, 26 comparative observational studies, and 22 noncomparative observational studies met inclusion criteria. Identified comparators were limited to placebo (RCTs) or usual care (observational studies). For intracranial hemorrhage, mortality was not improved with rFVIIa use across a range of doses. Arterial thromboembolism was increased with medium-dose rFVIIa use (risk difference [RD], 0.03 [95% CI, 0.01 to 0.06]) and high-dose rFVIIa use (RD, 0.06 [CI, 0.01 to 0.11]). For adult cardiac surgery, there was no mortality difference, but there was an increased risk for thromboembolism (RD, 0.05 [CI, 0.01 to 0.10]) with rFVIIa. For body trauma, there were no differences in mortality or thromboembolism, but there was a reduced risk for the acute respiratory distress syndrome (RD, -0.05 [CI, -0.02 to -0.08]). Mortality was higher in observational studies than in RCTs. LIMITATIONS The amount and strength of evidence were low for most outcomes and indications. Publication bias could not be excluded. CONCLUSION Limited available evidence for 5 off-label indications suggests no mortality reduction with rFVIIa use. For some indications, it increases thromboembolism.

Risk of cardiovascular disease from antiretroviral therapy for HIV: a systematic review.

Background Recent studies suggest certain antiretroviral therapy (ART) drugs are associated with increases in cardiovascular disease. Purpose We performed a systematic review and meta-analysis to summarize the available evidence, with the goal of elucidating whether specific ART drugs are associated with an increased risk of myocardial infarction (MI). Data Sources We searched Medline, Web of Science, the Cochrane Library, and abstract archives from the Conference on Retroviruses and Opportunistic Infections and International AIDS Society up to June 2011 to identify published articles and abstracts. Study Selection Eligible studies were comparative and included MI, strokes, or other cardiovascular events as outcomes. Data Extraction Eligibility screening, data extraction, and quality assessment were performed independently by two investigators. Data Synthesis Random effects methods and Fisher’s combined probability test were used to summarize evidence. Findings Twenty-seven studies met inclusion criteria, with 8 contributing to a formal meta-analysis. Findings based on two observational studies indicated an increase in risk of MI for patients recently exposed (usually defined as within last 6 months) to abacavir (RR 1.92, 95% CI 1.51–2.42) and protease inhibitors (PI) (RR 2.13, 95% CI 1.06–4.28). Our analysis also suggested an increased risk associated with each additional year of exposure to indinavir (RR 1.11, 95% CI 1.05–1.17) and lopinavir (RR 1.22, 95% CI 1.01–1.47). Our findings of increased cardiovascular risk from abacavir and PIs were in contrast to four published meta-analyses based on secondary analyses of randomized controlled trials, which found no increased risk from cardiovascular disease. Conclusion Although observational studies implicated specific drugs, the evidence is mixed. Further, meta-analyses of randomized trials did not find increased risk from abacavir and PIs. Our findings that implicate specific ARTs in the observational setting provide sufficient evidence to warrant further investigation of this relationship in studies designed for that purpose.

Isolated Disease of the Proximal Left Anterior Descending Artery: Comparing the Effectiveness of Percutaneous Coronary Interventions and Coronary Artery Bypass Surgery

OBJECTIVES This study sought to systematically compare the effectiveness of percutaneous coronary intervention and coronary artery bypass surgery in patients with single-vessel disease of the proximal left anterior descending (LAD) coronary artery. BACKGROUND It is uncertain whether percutaneous coronary interventions (PCI) or coronary artery bypass grafting (CABG) surgery provides better clinical outcomes among patients with single-vessel disease of the proximal LAD. METHODS We searched relevant databases (MEDLINE, EMBASE, and Cochrane from 1966 to 2006) to identify randomized controlled trials that compared outcomes for patients with single-vessel proximal LAD assigned to either PCI or CABG. RESULTS We identified 9 randomized controlled trials that enrolled a total of 1,210 patients (633 received PCI and 577 received CABG). There were no differences in survival at 30 days, 1 year, or 5 years, nor were there differences in the rates of procedural strokes or myocardial infarctions, whereas the rate of repeat revascularization was significantly less after CABG than after PCI (at 1 year: 7.3% vs. 19.5%; at 5 years: 7.3% vs. 33.5%). Angina relief was significantly greater after CABG than after PCI (at 1 year: 95.5% vs. 84.6%; at 5 years: 84.2% vs. 75.6%). Patients undergoing CABG spent 3.2 more days in the hospital than those receiving PCI (95% confidence interval: 2.3 to 4.1 days, p < 0.0001), required more transfusions, and were more likely to have arrhythmias immediately post-procedure. CONCLUSIONS In patients with single-vessel, proximal LAD disease, survival was similar in CABG-assigned and PCI-assigned patients; CABG was significantly more effective in relieving angina and led to fewer repeat revascularizations.

Quality Improvement Strategies for Children With Asthma: A Systematic Review

OBJECTIVE To evaluate the evidence that quality improvement (QI) strategies can improve the processes and outcomes of outpatient pediatric asthma care. DATA SOURCES Cochrane Effective Practice and Organisation of Care Group database (January 1966 to April 2006), MEDLINE (January 1966 to April 2006), Cochrane Consumers and Communication Group database (January 1966 to May 2006), and bibliographies of retrieved articles. STUDY SELECTION Randomized controlled trials, controlled before-after trials, or interrupted time series trials of English-language QI evaluations. INTERVENTIONS Must have included 1 or more QI strategies for the outpatient management of children with asthma. MAIN OUTCOME MEASURES Clinical status (eg, spirometric measures); functional status (eg, days lost from school); and health services use (eg, hospital admissions). RESULTS Seventy-nine studies met inclusion criteria: 69 included at least some component of patient education, self-monitoring, or self-management; 13 included some component of organizational change; and 7 included provider education. Self-management interventions increased symptom-free days by approximately 10 days/y (P = .02) and reduced school absenteeism by about 0.1 day/mo (P = .03). Interventions of provider education and those that incorporated organizational changes were likely to report improvements in medication use. Quality improvement interventions that provided multiple educational sessions, had longer durations, and used combinations of instructional modalities were more likely to result in improvements for patients than interventions lacking these characteristics. CONCLUSIONS A variety of QI interventions improve the outcomes and processes of care for children with asthma. Use of similar outcome measures and thorough descriptions of interventions would advance the study of QI for pediatric asthma care.

Evaluating detection and diagnostic decision support systems for bioterrorism response.

We evaluated the usefulness of detection systems and diagnostic decision support systems for bioterrorism response. We performed a systematic review by searching relevant databases (e.g., MEDLINE) and Web sites for reports of detection systems and diagnostic decision support systems that could be used during bioterrorism responses. We reviewed over 24,000 citations and identified 55 detection systems and 23 diagnostic decision support systems. Only 35 systems have been evaluated: 4 reported both sensitivity and specificity, 13 were compared to a reference standard, and 31 were evaluated for their timeliness. Most evaluations of detection systems and some evaluations of diagnostic systems for bioterrorism responses are critically deficient. Because false-positive and false-negative rates are unknown for most systems, decision making on the basis of these systems is seriously compromised. We describe a framework for the design of future evaluations of such systems.

Implementing effective hypertension quality improvement strategies: barriers and potential solutions.

Many quality improvement strategies have focused on improving blood pressure control, and these strategies can target the patient, the provider, and/or the system. Strategies that seem to have the biggest effect on blood pressure outcomes are team change, patient education, facilitated relay of clinical information, and promotion of self‐management. Barriers to effective blood pressure control can affect the patient, the physician, the system, and/or “cues to action.”We review the barriers to achieving blood pressure control and describe current and potential creative strategies for optimizing blood pressure control. These include home‐based disease management, combined patient and provider education, and automatic decision support systems. Future research must address which components of quality improvement interventions are most successful in achieving blood pressure control.