Systematic review data extraction: cross-sectional study showed that experience did not increase accuracy.

OBJECTIVE: This study assessed the impact of systematic review and data extraction experience on the accuracy and efficiency of data extraction in systematic reviews. STUDY DESIGN AND SETTING: We conducted a prospective cross-sectional study from October to December 2006. Participants were classified as having minimal, moderate, or substantial experience in systematic reviews and data extraction. Three studies on insomnia treatment were extracted. Our primary outcome was the accuracy of data extraction. Data sets of each experience level were analyzed for errors in data extraction and results of meta-analyses. Additionally, the time required for completion of data extraction was compared. RESULTS: Error rates were similar across the various levels of experience and ranged from 28.3% to 31.2%. Mean rates for errors of omission (11.3-16.4%) were generally lower than those for errors of inaccuracy (13.9-17.9%). There were no significant differences in error rates or accuracy of meta-analysis results between groups. Time required approached significance, with minimally experienced participants requiring the most time. CONCLUSION: Overall, there were high error rates by participants at all experience levels; however, time required for extraction tended to decrease with experience. These results illustrate the need to develop strategies aimed at mastery of data extraction, rather than reliance on previous data extraction experience alone.

Systematic review of biomarkers of brain injury in term neonatal encephalopathy.

Although neonatal hypoxic-ischemic encephalopathy is a common cause of childhood developmental disability, its timing, duration, and outcomes are poorly defined. Biomarkers serve as surrogates for disease injury, evolution, and outcome, but no tissue biomarker in routine clinical use can help predict outcomes in term newborn encephalopathy. We reviewed biomarkers in human term neonatal encephalopathy, to determine if current biomarkers are strong enough for clinical use as predictors of outcomes. A comprehensive search of databases identified 110 publications that met our inclusion criteria, i.e., (1) newborns at >36 weeks; (2) neonatal encephalopathy as defined by the American College of Obstetrics and Gynecology; (3) the use of a serum, urine, or cerebrospinal fluid biomarker; and (4) reported outcomes beyond age 12 months. Of those 110 publications, 22 reported outcomes beyond age 12 months. In single reports, urine lactate (P < 0.001), first urine S100 (P < 0.0001), cord-blood interleukin-6 (P = 0.02), serum nonprotein-bound iron (P < 0.001), serum CD14 cell NFkappaB activation (P = 0.014), serum interleukin-8 (P = 0.03), and serum ionized calcium (P = 0.001) were potential predictors of death or abnormal outcomes. A meta-analysis identified serum interleukin-1b (P = 0.04, n = 3), serum interleukin-6 (P = 0.04, n = 2), cerebrospinal fluid neuron-specific enolase (P = 0.03, n = 3), and cerebrospinal fluid interleukin-1b (P = 0.003, n = 2) as putative predictors of abnormal outcomes in survivors, when measured before age 96 hours. Several serum, urine, and cerebrospinal fluid biomarkers of term neonatal encephalopathy may provide important information regarding long-term outcomes. None, however, were studied extensively enough to warrant routine clinical use. Validation of these markers, either alone or in combination, is required in the development of viable therapeutic interventions.

Clinical trials of meditation practices in health care: characteristics and quality.

OBJECTIVE: To provide a descriptive overview of the clinical trials assessing meditation practices for health care. DESIGN: Systematic review of the literature. Comprehensive searches were conducted in 17 electronic bibliographic databases through September 2005. Other sources of potentially relevant studies included hand searches, reference tracking, contacting experts, and gray literature searches. Included studies were clinical trials with 10 or more adult participants using any meditation practice, providing quantitative data on health-related outcomes, and published in English. Two independent reviewers assessed study relevance, extracted the data, and assessed the methodological quality of the studies. RESULTS: Four hundred clinical trials on meditation (72% described as randomized) were included in the review (publication years 1956-2005). Five broad categories of meditation practices were identified: mantra meditation, mindfulness meditation, yoga, t'ai chi, and qigong. The three most studied clinical conditions were hypertension, miscellaneous cardiovascular diseases, and substance abuse. Psychosocial measures were the most frequently reported outcomes. Outcome measures of psychiatric and psychological symptoms dominate the outcomes of interest. Overall, the methodological quality of clinical trials is poor, but has significantly improved over time by 0.014 points every year (95% CI, 0.005, 0.023). CONCLUSIONS: Most clinical trials on meditation practices are generally characterized by poor methodological quality with significant threats to validity in every major quality domain assessed. Despite a statistically significant improvement in the methodological quality over time, it is imperative that future trials on meditation be rigorous in design, execution, analysis, and the reporting of results.

Comparison of meta-analytic results of indirect, direct, and combined comparisons of drugs for chronic insomnia in adults: a case study.

BACKGROUND: Our Center recently conducted a systematic review of the manifestations and management of chronic insomnia in adults. The efficacy and safety of benzodiazepines and nonbenzodiazepines, relative to placebo, were compared indirectly. OBJECTIVES: Determine how the results of indirect comparisons made in the review compare with the results of direct comparisons, as well as with estimates derived from Bayesian mixed treatment comparisons. Establish general appropriateness of the use of results of indirect or mixed treatment comparisons. METHODS: Treatments were compared using frequentist direct, indirect, and combined methods, as well as Bayesian direct and mixed methods. RESULTS: Estimates for comparisons tended to be clinically and statistically similar across methods. Estimates obtained through indirect comparisons were not biased and were similar to those obtained through direct analysis. CONCLUSIONS: Results of indirect comparisons made in the review, accurately reflected the current evidence. Frequentist and Bayesian methods of analysis of indirect comparisons should be considered when performing meta-analyses.

Meditation practices for health: state of the research.

OBJECTIVES: To review and synthesize the state of research on a variety of meditation practices, including: the specific meditation practices examined; the research designs employed and the conditions and outcomes examined; the efficacy and effectiveness of different meditation practices for the three most studied conditions; the role of effect modifiers on outcomes; and the effects of meditation on physiological and neuropsychological outcomes. DATA SOURCES: Comprehensive searches were conducted in 17 electronic databases of medical and psychological literature up to September 2005. Other sources of potentially relevant studies included hand searches, reference tracking, contact with experts, and gray literature searches. REVIEW METHODS: A Delphi method was used to develop a set of parameters to describe meditation practices. Included studies were comparative, on any meditation practice, had more than 10 adult participants, provided quantitative data on health-related outcomes, and published in English. Two independent reviewers assessed study relevance, extracted the data and assessed the methodological quality of the studies. RESULTS: Five broad categories of meditation practices were identified (Mantra meditation, Mindfulness meditation, Yoga, Tai Chi, and Qi Gong). Characterization of the universal or supplemental components of meditation practices was precluded by the theoretical and terminological heterogeneity among practices. Evidence on the state of research in meditation practices was provided in 813 predominantly poor-quality studies. The three most studied conditions were hypertension, other cardiovascular diseases, and substance abuse. Sixty-five intervention studies examined the therapeutic effect of meditation practices for these conditions. Meta-analyses based on low-quality studies and small numbers of hypertensive participants showed that TM(R), Qi Gong and Zen Buddhist meditation significantly reduced blood pressure. Yoga helped reduce stress. Yoga was no better than Mindfulness-based Stress Reduction at reducing anxiety in patients with cardiovascular diseases. No results from substance abuse studies could be combined. The role of effect modifiers in meditation practices has been neglected in the scientific literature. The physiological and neuropsychological effects of meditation practices have been evaluated in 312 poor-quality studies. Meta-analyses of results from 55 studies indicated that some meditation practices produced significant changes in healthy participants. CONCLUSIONS: Many uncertainties surround the practice of meditation. Scientific research on meditation practices does not appear to have a common theoretical perspective and is characterized by poor methodological quality. Firm conclusions on the effects of meditation practices in healthcare cannot be drawn based on the available evidence. Future research on meditation practices must be more rigorous in the design and execution of studies and in the analysis and reporting of results.

The efficacy and safety of drug treatments for chronic insomnia in adults: a meta-analysis of RCTs.

BACKGROUND: Hypnotics have a role in the management of acute insomnia; however, the efficacy and safety of pharmacological interventions in the management of chronic insomnia is unclear. OBJECTIVE: The objective of this paper is to conduct a systematic review of the efficacy and safety of drug treatments for chronic insomnia in adults. DATA SOURCES: Twenty-one electronic databases were searched, up to July 2006. STUDY SELECTION: Randomized double-blind, placebo-controlled trials were eligible. Quality was assessed using the Jadad scale. Data were pooled using the random effects model. DATA SYNTHESIS: One hundred and five studies were included in the review. Sleep onset latency, as measured by polysomnography, was significantly decreased for benzodiazepines (BDZ), (weighted mean difference: -10.0 minutes; 95% CI: -16.6, -3.4), non-benzodiazepines (non-BDZ) (-12.8 minutes; 95% CI: -16.9, -8.8) and antidepressants (ADP) (-7.0 minutes; 95% CI: -10.7, -3.3). Sleep onset latency assessed by sleep diaries was also improved (BDZ: -19.6 minutes; 95% CI: -23.9, -15.3; non-BDZ: -17.0 minutes; 95% CI: -20.0, -14.0; ADP: -12.2 minutes; 95% CI: -22.3, -2.2). Indirect comparisons between drug categories suggest BDZ and non-BDZ have a similar effect. All drug groups had a statistically significant higher risk of harm compared to placebo (BDZ: risk difference [RD]: 0.15; non-BDZ RD: 0.07; and ADP RD: 0.09), although the most commonly reported adverse events were minor. Indirect comparisons suggest that non-BDZ are safer than BDZ. CONCLUSIONS: Benzodiazepines and non-benzodiazepines are effective treatments in the management of chronic insomnia, although they pose a risk of harm. There is also some evidence that antidepressants are effective and that they pose a risk of harm.

Single data extraction generated more errors than double data extraction in systematic reviews.

BACKGROUND AND OBJECTIVE: To conduct a pilot study to compare the frequency of errors that accompany single vs. double data extraction, compare the estimate of treatment effect derived from these methods, and compare the time requirements for these methods. METHODS: Reviewers were randomized to the role of data extractor or data verifier, and were blind to the study hypothesis. The frequency of errors associated with each method of data extraction was compared using the McNemar test. The data set for each method was used to calculate an efficacy estimate by each method, using standard meta-analytic techniques. The time requirement for each method was compared using a paired t-test. RESULTS: Single data extraction resulted in more errors than double data extraction (relative difference: 21.7%, P = .019). There was no substantial difference between methods in effect estimates for most outcomes. The average time spent for single data extraction was less than the average time for double data extraction (relative difference: 36.1%, P = .003). CONCLUSION: In the case that single data extraction is used in systematic reviews, reviewers and readers need to be mindful of the possibility for more errors and the potential impact these errors may have on effect estimates.

Efficacy and safety of exogenous melatonin for secondary sleep disorders and sleep disorders accompanying sleep restriction: meta-analysis.

OBJECTIVE: To conduct a systematic review of the efficacy and safety of exogenous melatonin in managing secondary sleep disorders and sleep disorders accompanying sleep restriction, such as jet lag and shiftwork disorder. DATA SOURCES: 13 electronic databases and reference lists of relevant reviews and included studies; Associated Professional Sleep Society abstracts (1999 to 2003). STUDY SELECTION: The efficacy review included randomised controlled trials; the safety review included randomised and non-randomised controlled trials. QUALITY ASSESSMENT: Randomised controlled trials were assessed by using the Jadad Scale and criteria by Schulz et al, and non-randomised controlled trials by the Downs and Black checklist. DATA EXTRACTION AND SYNTHESIS: One reviewer extracted data and another reviewer verified the data extracted. The inverse variance method was used to weight studies and the random effects model was used to analyse data. MAIN RESULTS: Six randomised controlled trials with 97 participants showed no evidence that melatonin had an effect on sleep onset latency in people with secondary sleep disorders (weighted mean difference -13.2 (95% confidence interval -27.3 to 0.9) min). Nine randomised controlled trials with 427 participants showed no evidence that melatonin had an effect on sleep onset latency in people who had sleep disorders accompanying sleep restriction (-1.0 (-2.3 to 0.3) min). 17 randomised controlled trials with 651 participants showed no evidence of adverse effects of melatonin with short term use (three months or less). CONCLUSIONS: There is no evidence that melatonin is effective in treating secondary sleep disorders or sleep disorders accompanying sleep restriction, such as jet lag and shiftwork disorder. There is evidence that melatonin is safe with short term use.

Myocardial subproteomic analysis of a constitutively active Rac1-expressing transgenic mouse with lethal myocardial hypertrophy.

A two-dimensional gel electrophoresis (2-DE)-based proteomic approach was used to study a transgenic mouse model of acerbated dilated cardiomyopathy in which the small monomeric GTPase, Rac1, was constitutively expressed exclusively in the myocardium. A subfractionation procedure allowed for the focused analysis of both cytoplasmic and myofilament protein-enriched extracts of ventricular tissue from Rac1 transgenic and age-matched nontransgenic (NTG) mice. The majority of these mice displayed severe hypertrophy (heart-to-body weight ratios >2-fold greater in the Rac1 mice) and died from overt heart failure between days 14 and 17. Comparative 2-DE analysis (pH 3-10, 12% SDS-PAGE) derived from Rac1 (n = 4) and NTG (n = 4) groups revealed differences in mean protein spot intensities. Twelve proteins from the cytoplasmic protein-enriched extract met our criteria for robustness and spot resolution and were identified. These proteins represent a broad distribution of cellular functions with only some previously implicated in myocardial hypertrophy. The myofilament subproteome displayed no change in posttranslational modification, but further analysis by one-dimensional Western blot showed increased quantities of myofilament proteins in the Rac1 mouse ventricles. Additionally, three proteins with different functionality that were altered in the cytoplasmic protein-enriched subproteome, tubulin beta-chain, manganese superoxide dismutase, and malate dehydrogenase, were analyzed at days 7, 9, and 11 to assess their role in the development of the dilated cardiomyopathic phenotype. The quantity of all three proteins peaked at day 9, suggesting an early response in cardiac hypertrophic failure.

Challenges in systematic reviews of complementary and alternative medicine topics.

The use of complementary and alternative medicine (CAM) continues to grow in the United States. The Agency for Healthcare Research and Quality has devoted a substantial proportion of the Evidence-based Practice Center (EPC) program to systematic reviews of CAM. Such syntheses present different challenges from those conducted on western medicine topics, and in many ways are more difficult. We discuss 3 challenges: identifying evidence about CAM, assessing the quality of individual studies, and addressing rare serious adverse events. We use illustrations from EPC evidence reports to show readers approaches to the 3 areas and then present specific recommendations for each issue.

The efficacy and safety of exogenous melatonin for primary sleep disorders. A meta-analysis.

BACKGROUND: Exogenous melatonin has been increasingly used in the management of sleep disorders. PURPOSE: To conduct a systematic review of the efficacy and safety of exogenous melatonin in the management of primary sleep disorders. DATA SOURCES: A number of electronic databases were searched. We reviewed the bibliographies of included studies and relevant reviews and conducted hand-searching. STUDY SELECTION: Randomized controlled trials (RCTs) were eligible for the efficacy review, and controlled trials were eligible for the safety review. DATA EXTRACTION: One reviewer extracted data, while the other verified data extracted. The Random Effects Model was used to analyze data. DATA SYNTHESIS: Melatonin decreased sleep onset latency (weighted mean difference [WMD]: -11.7 minutes; 95% confidence interval [CI]: -18.2, -5.2)); it was decreased to a greater extent in people with delayed sleep phase syndrome (WMD: -38.8 minutes; 95% CI: -50.3, -27.3; n=2) compared with people with insomnia (WMD: -7.2 minutes; 95% CI: -12.0, -2.4; n=12). The former result appears to be clinically important. There was no evidence of adverse effects of melatonin. CONCLUSIONS: There is evidence to suggest that melatonin is not effective in treating most primary sleep disorders with short-term use (4 weeks or less); however, additional large-scale RCTs are needed before firm conclusions can be drawn. There is some evidence to suggest that melatonin is effective in treating delayed sleep phase syndrome with short-term use. There is evidence to suggest that melatonin is safe with short-term use (3 months or less).

Phosphorylation and mutation of human cardiac troponin I deferentially destabilize the interaction of the functional regions of troponin I with troponin C.

We have utilized 2D [(1)H,(15)N]HSQC NMR spectroscopy to elucidate the binding of three segments of cTnI in native, phosphorylated, and mutated states to cTnC. The near N-terminal region (cRp; residues 34-71) contains the protein kinase C (PKC) phosphorylation sites S41 and S43, the inhibitory region (cIp; residues 128-147) contains another PKC site T142 and a familial hypertrophic cardiomyopathy (FHC) mutation R144G, and the switch region (cSp; residues 147-163) contains the novel p21-activated kinase (PAK) site S149 and another FHC mutation R161W. While S41/S43 phosphorylation of cRp had minimal disruption in the interaction of cRp and cTnC.3Ca(2+), T142 phosphorylation reduced the affinity of cIp for cCTnC.2Ca(2+) by approximately 14-fold and S149 phosphorylation reduced the affinity of cSp for cNTnC.Ca(2+) by approximately 10-fold. The mutation R144G caused an approximately 6-fold affinity decrease of cIp for cCTnC.2Ca(2+) and mutation R161W destabilized the interaction of cSp and cNTnC.Ca(2+) by approximately 1.4-fold. When cIp was both T142 phosphorylated and R144G mutated, its affinity for cCTnC.2Ca(2+) was reduced approximately 19-fold, and when cSp was both S149 phosphorylated and R161W mutated, its affinity for cNTnC.Ca(2+) was reduced approximately 4-fold. Thus, while the FHC mutation R144G enhances the effect of T142 phosphorylation on the interaction of cIp and cCTnC.2Ca(2+), the FHC mutation R161W suppresses the effect of S149 phosphorylation on the interaction of cSp and cNTnC.Ca(2+), demonstrating linkages between the FHC mutation and phosphorylation of cTnI. The observed alterations corroborate well with structural data. These results suggest that while the modifications in the cRp region have minimal influence, those in the key functional cIp-cSp region have a pronounced effect on the interaction of cTnI and cTnC, which may correlate with the altered myofilament function and cardiac muscle contraction under pathophysiological conditions.

Proteomic analysis of Rac1 transgenic mice displaying dilated cardiomyopathy reveals an increase in creatine kinase M-chain protein abundance.

Here, we demonstrate the application of the proteomic approach to the study of a transgenic mouse model of heart failure and provide an example of a disease-associated protein alteration that can be observed using this approach. Specifically, we applied the proteomic approach to the analysis of a mouse model of dilated cardiomyopathy in which the small GTPase, Rac1, was constitutively expressed specifically in the myocardium. We utilized the methods of two-dimensional gel electrophoresis (2-DE) for protein separation, silver-staining for protein visualization and mass spectrometry (MALDI-TOF and MS/MS) for protein spot identification. Computer-generated composite images were created which represent a normalized average of four 2-DE gel images derived from analysis of either Rac1 transgenic (n = 4) or non-transgenic (n = 4) mice. Analysis of composite images derived from NTG and Rac1 experimental groups revealed numerous statistically significant differences in mean protein spot intensities. Here, we report a statistically significant increase, of approximately 1.6-fold, in the mean protein spot intensity for creatine kinase M-chain in the composite image of Rac1 transgenic mice compared to control. This protein alteration may be consistent with an end-stage heart failure phenotype in which maximal myocardial reserve is employed to sustain survival.

p21-activated kinase increases the calcium sensitivity of rat triton-skinned cardiac muscle fiber bundles via a mechanism potentially involving novel phosphorylation of troponin I.

Phosphorylation of myofilament proteins by kinases such as cAMP-dependent protein kinase and protein kinase C has been shown to lead to altered thin-filament protein-protein interactions and modulation of cardiac function in vitro. In the present study, we report that a small GTPase-dependent kinase, p21-activated kinase (PAK), increases the calcium sensitivity of Triton-skinned cardiac muscle fiber bundles. Constitutively active PAK3 caused an average 1.25-fold (25.0+/-6.0%, n=6) increase in force at pCa 5.75, 1.44-fold (44.0+/-7.78%, n=6) at pCa 6.25, and 2.41-fold (141.2+/-23.7%, n=4) at pCa 6.5, representing a change in pCa50 value of approximately 0.25. Constitutively active PAK3 produced no change in force under conditions of relaxation (pCa 8.0) or maximal contraction (pCa 4.5). Furthermore, an inactive, kinase-dead form of PAK3 failed to produce any change in force development at any pCa value. The myofilament proteins phosphorylated by PAK3, at pCa 6.5, are desmin, troponin T, troponin I, and an unidentified 70-kDa protein. Importantly, cardiac troponin I was found to be phosphorylated at serine 149 of human cardiac troponin I, representing a novel phosphorylation site. These findings suggest a novel mechanism of modulating the calcium sensitivity of cardiac muscle contraction.