Olivia J Phung

Effect of green tea catechins with or without caffeine on anthropometric measures: a systematic review and meta-analysis

BACKGROUND Green tea catechins (GTCs) with or without caffeine have been studied in randomized controlled trials (RCTs) for their effect on anthropometric measures and have yielded conflicting results. OBJECTIVE The objective was to perform a systematic review and meta-analysis of RCTs of GTCs on anthropometric variables, including body mass index (BMI), body weight, waist circumference (WC), and waist-to-hip ratio (WHR). DESIGN A systematic literature search of MEDLINE, EMBASE, CENTRAL, and the Natural Medicines Comprehensive Database was conducted through April 2009. RCTs that evaluated GTCs with or without caffeine and that reported BMI, body weight, WC, or WHR were included. The weighted mean difference of change from baseline (with 95% CIs) was calculated by using a random-effects model. RESULTS Fifteen studies (n = 1243 patients) met the inclusion criteria. On meta-analysis, GTCs with caffeine decreased BMI (-0.55; 95% CI: -0.65, -0.40), body weight (-1.38 kg; 95% CI: -1.70, -1.06), and WC (-1.93 cm; 95% CI: -2.82, -1.04) but not WHR compared with caffeine alone. GTC ingestion with caffeine also significantly decreased body weight (-0.44 kg; 95% CI: -0.72, -0.15) when compared with a caffeine-free control. Studies that evaluated GTCs without concomitant caffeine administration did not show benefits on any of the assessed anthropometric endpoints. CONCLUSIONS The administration of GTCs with caffeine is associated with statistically significant reductions in BMI, body weight, and WC; however, the clinical significance of these reductions is modest at best. Current data do not suggest that GTCs alone positively alter anthropometric measurements.

Green Tea Catechins Decrease Total and Low-Density Lipoprotein Cholesterol: A Systematic Review and Meta-Analysis

Green tea catechins (GTCs) have been studied in randomized control trials for their lipid-lowering effects. Studies, however, have been small and demonstrated conflicting results. The objective of this study was to perform a systematic review and meta-analysis of randomized controlled trials evaluating the relationship between GTCs and serum lipid levels, including total, low-density lipoprotein (LDL), high-density lipoprotein (HDL) cholesterol, and triglycerides. A systematic literature search of MEDLINE, EMBASE, Cochrane CENTRAL, and the Natural Medicines Comprehensive Database was conducted through March 2010. Randomized controlled trials evaluating GTCs vs control in human beings and reporting efficacy data on at least one of the aforementioned serum lipid endpoints were included. Weighted mean differences for changes from baseline (with 95% confidence intervals [CIs]) for lipid endpoints were calculated using random-effects models. Twenty trials (N=1,415) met all inclusion criteria. Upon meta-analysis, GTCs at doses ranging from 145 to 3,000 mg/day taken for 3 to 24 weeks reduced total (-5.46 mg/dL [-0.14 mmol/L]; 95% CI -9.59 to -1.32) and LDL cholesterol (-5.30 mg/dL [-0.14 mmol/L]; 95% CI -9.99 to -0.62) compared to control. GTCs did not significantly alter HDL cholesterol (-0.27 mg/dL [-0.007 mmol/L]; 95% CI -1.62 to 1.09) or triglyceride (3.00 mg/dL [-0.034 mmol/L]; 95% CI -2.73 to 8.73) levels. The consumption of GTCs is associated with a statistically significant reduction in total and LDL cholesterol levels; however, there was no significant effect on HDL cholesterol or triglyceride levels.

Sulphonylureas and risk of cardiovascular disease: systematic review and meta-analysis

Sulphonylurea use has been linked with increased cardiovascular disease risk; however, previous studies have been inconsistent. Type 2 diabetes independently increases risk for cardiovascular disease, so understanding the link between longer‐term use of anti‐diabetic medications and cardiovascular disease has important clinical implications.

Systematic Review and Adjusted Indirect Comparison Meta-Analysis of Oral Anticoagulants in Atrial Fibrillation

Background—Oral anticoagulants such as apixaban, dabigatran, and rivaroxaban are alternatives to warfarin for preventing events in patients with atrial fibrillation. Direct comparative studies between agents are unavailable. Our objective was to conduct an adjusted indirect comparison meta-analysis between new oral agents in atrial fibrillation. Methods and Results—We searched MEDLINE and Cochrane Central through February 2012 for randomized, controlled trials in patients with atrial fibrillation evaluating apixaban, dabigatran, or rivaroxaban versus warfarin. For dabigatran, only data from the Food and Drug Administration–approved dose were included. Outcomes included the composite of stroke or systemic embolism, any stroke, and major bleeding among, others. Outcomes were initially pooled using standard random-effects methods, producing risk ratio and 95% confidence intervals. Adjusted indirect comparisons using these pooled estimates were then performed. A total of 44 733 patients from 4 studies were analyzed. Most analyses yielded no differences between agents. Dabigatran lowered risk of composite outcome (risk ratio, 0.75; 95% confidence interval, 0.57–1.00), ischemic stroke (0.67; 0.48–0.93), and hemorrhagic stroke (0.45; 0.45–0.99) versus rivaroxaban. No differences in all strokes or mortality were seen. Apixaban lowered the risk of major bleeding (0.74; 0.60–0.91) and gastrointestinal bleeding (0.58; 0.41–0.82) versus dabigatran and major bleeding versus rivaroxaban (0.68; 0.55–0.83), but increased systemic emboli versus rivaroxaban (3.86; 1.17–12.75). Conclusions—Significant differences in efficacy and safety parameters may exist between oral anticoagulant agents in patients with atrial fibrillation. Apixaban lowers the risk of major and gastrointestinal bleeding versus dabigatran and rivaroxaban. Dabigatran lowers the composite of stroke or systemic emboli, and ischemic stroke versus rivaroxaban. Head-to-head clinical trials are required to confirm these findings.

Cinnamon Use in Type 2 Diabetes: An Updated Systematic Review and Meta-Analysis

PURPOSE Cinnamon has been studied in randomized controlled trials (RCTs) for its glycemic-lowering effects, but studies have been small and show conflicting results. A prior meta-analysis did not show significant results, but several RCTs have been published since then. We conducted an updated systematic review and meta-analysis of RCTs evaluating cinnamon’s effect on glycemia and lipid levels. METHODS MEDLINE, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched through February 2012. Included RCTs evaluated cinnamon compared with control in patients with type 2 diabetes and reported at least one of the following: glycated hemoglobin (A1c), fasting plasma glucose, total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), or triglycerides. Weighted mean differences (with 95% confidence intervals) for endpoints were calculated using random-effects models. RESULTS In a meta-analysis of 10 RCTs (n = 543 patients), cinnamon doses of 120 mg/d to 6 g/d for 4 to 18 weeks reduced levels of fasting plasma glucose (−24.59 mg/dL; 95% CI, −40.52 to −8.67 mg/dL), total cholesterol (−15.60 mg/dL; 95% CI, −29.76 to −1.44 mg/dL), LDL-C (−9.42 mg/dL; 95% CI, −17.21 to −1.63 mg/dL), and triglycerides (−29.59 mg/dL; 95% CI, −48.27 to −10.91 mg/dL). Cinnamon also increased levels of HDL-C (1.66 mg/dL; 95% CI, 1.09 to 2.24 mg/dL). No significant effect on hemoglobin A1c levels (−0.16%; 95%, CI −0.39% to 0.02%) was seen. High degrees of heterogeneity were present for all analyses except HDL-C (I2 ranging from 66.5% to 94.72%). CONCLUSIONS The consumption of cinnamon is associated with a statistically significant decrease in levels of fasting plasma glucose, total cholesterol, LDL-C, and triglyceride levels, and an increase in HDL-C levels; however, no significant effect on hemoglobin A1c was found. The high degree of heterogeneity may limit the ability to apply these results to patient care, because the preferred dose and duration of therapy are unclear.

Lifestyle modification programs in polycystic ovary syndrome: systematic review and meta-analysis.

CONTEXT Polycystic ovary syndrome (PCOS) is a prevalent disorder that affects women of childbearing age and may be related to obesity and insulin resistance. OBJECTIVE The purpose of this systematic review was to appraise the evidence of the impact of lifestyle modification (LSM) interventions on outcomes of women with PCOS. DATA SOURCES Sources included Ovid Medline, OVID Embase, OVID Cochrane Library, Web of Science, Scopus, PsycINFO, and CINAHL (up to January 2011). STUDY SELECTION We included randomized controlled trials that enrolled woman of any age with PCOS who received LSM and compared them against women who received no intervention, minimal intervention, or metformin. DATA EXTRACTION Two authors performed the data extraction independently. DATA SYNTHESIS We included 9 trials enrolling 583 women with a high loss to follow-up rate, lack of blinding, and short follow-up. Compared with minimal intervention, LSM significantly reduced fasting blood glucose (weighted mean difference, -2.3 mg/dL; 95% confidence interval, -4.5 to -0.1, I² = 72%, P = .04) and fasting blood insulin (weighted mean difference, -2.1 μU/mL, 95% confidence interval, -3.3 to -1.0, I² = 0%, P < .001). Changes in body mass index were associated with changes in fasting blood glucose (P < .001). Metformin was not significantly better than LSM in improving blood glucose or insulin levels. We found no significant effect of LSM on pregnancy rate, and the effect on hirsutism was unclear. CONCLUSIONS The available evidence suggests that LSM reduces fasting blood glucose and insulin levels in women with PCOS. Metformin has similar effects. Translation of these short-term effects to patient-important outcomes, beyond diabetes prevention, remains uncertain.

The Comparative Efficacy of Plant Sterols and Stanols on Serum Lipids: A Systematic Review and Meta-Analysis

BACKGROUND Plant sterols and stanols are plant steroids with a similar chemical structure and cellular function to human cholesterol, and are recommended as dietary modifiers of serum lipids. Plant sterols have a higher degree of absorption than plant stanols, suggesting differential efficacy between the two. DESIGN A meta-analysis of randomized controlled trials was performed to summarize direct comparisons between the effect of plant sterols vs plant stanols on serum lipid levels in healthy patients and patients with hypercholesterolemia. METHODS A systematic literature search of MEDLINE, EMBASE, Cochrane CENTRAL, and the Natural Medicines Comprehensive Database was conducted from January 1950 through January 2009. Trials were included in the analysis if they were randomized controlled trials evaluating the effect of plant sterols vs plant stanols in healthy patients or patients with hypercholesterolemia who reported efficacy data on total, low-density lipoprotein, and high-density lipoprotein cholesterols or triglycerides. The weighted mean difference (WMD) of the change from baseline (in mg/dL) with 95% confidence interval was calculated as the difference between the means in the plant sterol and plant stanol groups using a random-effects model. RESULTS Fourteen studies (n=531 patients) met the inclusion criteria. Upon meta-analysis, the results showed that there is no statistically or clinically significant difference between plant sterols and plant stanols in their abilities to modify total cholesterol (WMD -1.11 mg/dL [-0.0286 mmol/L], 95% confidence interval [CI] -4.12 to 1.90, P=0.47), low-density lipoprotein cholesterol (WMD -0.35 mg/dL [-0.0091 mmol/L], 95% CI -2.98 to 2.28, P=0.79), high-density lipoprotein cholesterol (WMD -0.28 mg/dL [-0.00073 mmol/L], 95% CI -1.18 to 0.62, P=0.54), or triglycerides (WMD -1.80 mg/dL [-0.0203 mmol/L], 95% CI -6.80 to 3.21, P=0.48). CONCLUSIONS Plant sterols and plant stanols do not have statistically or clinically relevant differing effects on total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or triglyceride levels. The selection of plant sterols vs plant stanols should then be based on potential differences in safety parameters and further study is required to elucidate such differences.

Early combination therapy for the treatment of type 2 diabetes mellitus: systematic review and meta-analysis

Guidelines for type 2 diabetes recommend add‐on agents when metformin alone fails to provide adequate glycaemic control. However, early combination therapy may benefit health outcomes. We conducted a systematic review and meta‐analysis to investigate this question.

Almonds have a neutral effect on serum lipid profiles: a meta-analysis of randomized trials.

Almond consumption may be associated with improvements in serum lipid profiles. The aim was to evaluate the influence of almonds on lipid parameters to help define the role of almonds as a lipid modulator. MEDLINE, EMBASE, Cochrane CENTRAL, and the Natural Medicines Comprehensive Database were searched through July 2008, with no language restrictions, for randomized controlled trials of almonds in human patients that reported efficacy data on at least one of the following endpoints: total, low-density lipoprotein (LDL), or high-density lipoprotein (HDL) cholesterol, triglycerides, or the LDL:HDL ratio. A manual search of references from primary or review articles was performed to identify additional relevant trials. Five randomized, controlled trials (totaling 142 participants) met all inclusion criteria. Upon meta-analysis, almond consumption ranging from 25 to 168 g/day significantly lowered total cholesterol [weighted mean difference -6.95 mg/dL (95% confidence interval [CI] -13.12 to -0.772) (-0.18 mmol/L [95% CI -0.34 to -0.02])] and showed a strong trend toward reducing LDL cholesterol [weighted mean difference -5.79 mg/dL (95% CI -11.2 to 0.00) (-0.15 mmol/L [95% CI -0.29 to 0.00])]. No significant effect on HDL cholesterol, triglycerides, or LDL:HDL ratio was found. No statistical heterogeneity was observed for any analysis (I2=0% for all). Review of funnel plots and the Eggers weighted regression statistic P values suggested a low likelihood of publication bias in all analyses (P>0.25 for all). Almond consumption may decrease total cholesterol and does not significantly affect LDL or HDL cholesterol, triglycerides, or the LDL:HDL ratio. The current body of randomized trials does not support the ingestion of almonds solely for their lipid modifying effects. Both the lipid modulating effects and the safety/tolerability of almonds should be further investigated through the conduction of larger randomized, double-blinded trials of longer duration. Such studies might focus specifically on whether the efficacy of almonds as a lipid modulator varies by dose or comorbidity.

Pharmacologic Interventions for Painful Diabetic Neuropathy: An Umbrella Systematic Review and Comparative Effectiveness Network Meta-analysis

BACKGROUND Multiple treatments for painful diabetic peripheral neuropathy are available. PURPOSE To evaluate the comparative effectiveness of oral and topical analgesics for diabetic neuropathy. DATA SOURCES Multiple electronic databases between January 2007 and April 2014, without language restriction. STUDY SELECTION Parallel or crossover randomized, controlled trials that evaluated pharmacologic treatments for adults with painful diabetic peripheral neuropathy. DATA EXTRACTION Duplicate extraction of study data and assessment of risk of bias. DATA SYNTHESIS 65 randomized, controlled trials involving 12 632 patients evaluated 27 pharmacologic interventions. Approximately one half of these studies had high or unclear risk of bias. Nine head-to-head trials showed greater pain reduction associated with serotonin-norepinephrine reuptake inhibitors (SNRIs) than anticonvulsants (standardized mean difference [SMD], -0.34 [95% credible interval {CrI}, -0.63 to -0.05]) and with tricyclic antidepressants (TCAs) than topical capsaicin 0.075%. Network meta-analysis showed that SNRIs (SMD, -1.36 [CrI, -1.77 to -0.95]), topical capsaicin (SMD, -0.91 [CrI, -1.18 to -0.08]), TCAs (SMD, -0.78 [CrI, -1.24 to -0.33]), and anticonvulsants (SMD, -0.67 [CrI, -0.97 to -0.37]) were better than placebo for short-term pain control. Specifically, carbamazepine (SMD, -1.57 [CrI, -2.83 to -0.31]), venlafaxine (SMD, -1.53 [CrI, -2.41 to -0.65]), duloxetine (SMD, -1.33 [CrI, -1.82 to -0.86]), and amitriptyline (SMD, -0.72 [CrI, -1.35 to -0.08]) were more effective than placebo. Adverse effects included somnolence and dizziness with TCAs, SNRIs, and anticonvulsants; xerostomia with TCAs; and peripheral edema and burning sensation with pregabalin and capsaicin. LIMITATION Confidence in findings was limited because most evidence came from indirect comparisons of trials with short (≤3 months) follow-up and unclear or high risk of bias. CONCLUSION Several medications may be effective for short-term management of painful diabetic neuropathy, although their comparative effectiveness is unclear. PRIMARY FUNDING SOURCE Mayo Foundation for Medical Education and Research.