Correction to: Global dietary calcium intake among adults: a systematic review.

The original Electronic Supplementary Material file 3 contained an erroneous reference for Mali. A link to the corrected file is provided here.

Global dietary calcium intake among adults: a systematic review.

Low calcium intake may adversely affect bone health in adults. Recognizing the presence of low calcium intake is necessary to develop national strategies to optimize intake. To highlight regions where calcium intake should be improved, we systematically searched for the most representative national dietary calcium intake data in adults from the general population in all countries. We searched 13 electronic databases and requested data from domain experts. Studies were double-screened for eligibility. Data were extracted into a standard form. We developed an interactive global map, categorizing countries based on average calcium intake and summarized differences in intake based on sex, age, and socioeconomic status. Searches yielded 9780 abstracts. Across the 74 countries with data, average national dietary calcium intake ranges from 175 to 1233 mg/day. Many countries in Asia have average dietary calcium intake less than 500 mg/day. Countries in Africa and South America mostly have low calcium intake between about 400 and 700 mg/day. Only Northern European countries have national calcium intake greater than 1000 mg/day. Survey data for three quarters of available countries were not nationally representative. Average calcium intake is generally lower in women than men, but there are no clear patterns across countries regarding relative calcium intake by age, sex, or socioeconomic status. The global calcium map reveals that many countries have low average calcium intake. But recent, nationally representative data are mostly lacking. This review draws attention to regions where measures to increase calcium intake are likely to have skeletal benefits.

Subgroup analyses in randomized controlled trials: the need for risk stratification in kidney transplantation.

Although randomized controlled trials (RCT) are the gold standard for establishing causation in clinical research, their aggregated results can be misleading when applied to individual patients. A treatment may be beneficial in some patients, but its harms may outweigh benefits in others. While conventional one-variable-at-a-time subgroup analyses have well-known limitations, multivariable risk-based analyses can help uncover clinically significant heterogeneity in treatment effects that may be otherwise obscured. Trials in kidney transplantation have yielded the finding that a reduction in acute rejection does not translate into a similar benefit in prolonging graft survival and improving graft function. This paradox might be explained by the variation in risk for acute rejection among included kidney transplant recipients varying the likelihood of benefit or harm from intense immunosuppressive regimens. Analyses that stratify patients by their immunological risk may resolve these otherwise puzzling results. Reliable risk models should be developed to investigate benefits and harms in rationally designed risk-based subgroups of patients in existing RCT data sets. These risk strata would need to be validated in future prospective clinical trials examining long-term effects on patient and graft survival. This approach may allow better individualized treatment choices for kidney transplant recipients.

KDIGO clinical practice guideline for the care of kidney transplant recipients: a summary

The 2009 Kidney Disease: Improving Global Outcomes (KDIGO) clinical practice guideline on the monitoring, management, and treatment of kidney transplant recipients is intended to assist the practitioner caring for adults and children after kidney transplantation. The guideline development process followed an evidence-based approach, and management recommendations are based on systematic reviews of relevant treatment trials. Critical appraisal of the quality of the evidence and the strength of recommendations followed the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach. The guideline makes recommendations for immunosuppression and graft monitoring, as well as prevention and treatment of infection, cardiovascular disease, malignancy, and other complications that are common in kidney transplant recipients, including hematological and bone disorders. Limitations of the evidence, especially the lack of definitive clinical outcome trials, are discussed and suggestions are provided for future research. This summary includes a brief description of methodology and the complete guideline recommendations but does not include the rationale and references for each recommendation, which are published elsewhere.

Accuracy of biomarkers to diagnose acute cardiac ischemia in the emergency department: a meta-analysis.

STUDY OBJECTIVE: We sought to evaluate quantitatively the evidence on the diagnostic performance of presentation and serial biochemical markers for emergency department diagnosis of acute cardiac ischemia (ACI), including acute myocardial infarction (AMI) and unstable angina. METHODS: We conducted a systematic review and meta-analysis of the English-language literature published between 1966 and December 1998. We examined the diagnostic performance of creatine kinase, creatine kinase-MB, myoglobin, and troponin I and T testing. Diagnostic performance was assessed by using estimates of test sensitivity and specificity and was summarized by summary receiver-operating characteristic curves. RESULTS: Only 4 studies were found that evaluated all patients with ACI; 73 were found that focused only on a diagnosis of AMI. To diagnose ACI, presentation biomarker tests had sensitivities of 16% to 19% and specificities of 96% to 100%; serial biomarker tests had sensitivities of 31% to 45% and specificities of 95% to 98%. Considering only the diagnosis of AMI, presentation biomarker tests had summary sensitivities of 37% to 49% and summary specificities of 87% to 97%; serial biomarker tests had summary sensitivities of 79% to 93% and summary specificities of 85% to 96%. Variation of test sensitivity was best explained by test timing. Longer symptom duration or time between serial tests yielded higher sensitivity. CONCLUSION: The limited evidence available to evaluate the diagnostic accuracy of biomarkers for ACI suggests that biomarkers have very low sensitivity to diagnose ACI. Thus, biomarkers alone will greatly underdiagnose ACI and will be inadequate to make triage decisions. For AMI diagnosis alone, multiple testing of individual biomarkers over time substantially improves sensitivity, while retaining high specificity, at the expense of additional time. Further high-quality studies are needed on the clinical effect of using biomarkers for patients with ACI in the ED and on optimal timing of serial testing and in combination with other tests.

Diagnosing acute cardiac ischemia in the emergency department: a systematic review of the accuracy and clinical effect of current technologies.

STUDY OBJECTIVE: Acute cardiac ischemia (ACI) encompasses the diagnoses of unstable angina pectoris and acute myocardial infarction (AMI). Accurate diagnosis and triage of patients with ACI in the emergency department should increase survival for these patients and reduce unnecessary hospital admissions. METHODS: We conducted a systematic review of the English-language literature published between 1966 and December 1998 on the accuracy and clinical effect of diagnostic technologies for ACI. We evaluated prospective and retrospective studies of adult patients who presented to the ED with symptoms suggesting ACI. Outcomes were diagnostic performance (test sensitivity and specificity) and measures of clinical effect. Meta-analyses were performed when appropriate. A decision and cost-effectiveness analysis was conducted that investigated various diagnostic strategies used in the diagnosis of ACI in the ED. RESULTS: We screened 6,667 abstracts, reviewed 407 full articles, and included 106 articles articles in the main analysis. Single measurements of biomarkers at presentation to the ED have low sensitivity for AMI, although they have high specificity. Serial measurements greatly increase the sensitivity for AMI while maintaining their excellent specificity. Diagnostic technologies to evaluate ACI in selected populations, such as electrocardiography, sestamibi perfusion imaging, and stress ECG, may have very good to excellent sensitivity; however, they have not been sufficiently studied. The Goldman Chest Pain Protocol has good sensitivity (about 90%) for AMI but has not been shown to result in any differences in hospitalization rate, length of stay, or estimated costs in the single clinical effect study performed. Its applicability to patients with unstable angina pectoris has not been evaluated. The use of an Acute Cardiac Ischemia-Time-Insensitive Predictive Instrument led to the appropriate triage of 97% of patients with ACI presenting to the ED and reduced unnecessary hospitalizations. CONCLUSION: Many of the current technologies remain underevaluated, especially regarding their clinical effect. The extent to which combinations of tests may provide better accuracy than any single test needs further study.

Strategies for diagnosing and treating suspected acute bacterial sinusitis: a cost-effectiveness analysis.

OBJECTIVE: Symptoms suggestive of acute bacterial sinusitis are common. Available diagnostic and treatment options generate substantial costs with uncertain benefits. We assessed the cost-effectiveness of alternative management strategies to identify the optimal approach. DESIGN: For such patients, we created a Markov model to examine four strategies: 1) no antibiotic treatment; 2) empirical antibiotic treatment; 3) clinical criteria-guided treatment; and 4) radiography-guided treatment. The model simulated a 14-day course of illness, included sinusitis prevalence, antibiotic side effects, sinusitis complications, direct and indirect costs, and symptom severity. Strategies costing less than 50,000 dollars per quality-adjusted life year gained were considered "cost-effective." MEASUREMENTS AND MAIN RESULTS: For mild or moderate disease, basing antibiotic treatment on clinical criteria was cost-effective in clinical settings where sinusitis prevalence is within the range of 15% to 93% or 3% to 63%, respectively. For severe disease, or to prevent sinusitis or antibiotic side effect symptoms, use of clinical criteria was cost-effective in settings with lower prevalence (below 51% or 44%, respectively); empirical antibiotics was cost-effective with higher prevalence. Sinus radiography-guided treatment was never cost-effective for initial treatment. CONCLUSIONS: Use of a simple set of clinical criteria to guide treatment is a cost-effective strategy in most clinical settings. Empirical antibiotics are cost-effective in certain settings; however, their use results in many unnecessary prescriptions. If this resulted in increased antibiotic resistance, costs would substantially rise and efficacy would fall. Newer, expensive antibiotics are of limited value. Additional testing is not cost-effective. Further studies are needed to find an accurate,low-cost diagnostic test for acute bacterial sinusitis.