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Results for “Meta- analysis”

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At least 1,621 records · Page 90Linked to original sources

PubMed2005

Vertebral fracture risk reduction with risedronate in post-menopausal women with osteoporosis: a meta-analysis of individual patient data.

BACKGROUND AND AIMS: The effect of risedronate, a potent pyridinyl bisphosphonate, on vertebral fractures in post-menopausal women was evaluated in randomized, placebo-controlled clinical trials. These trials included two large vertebral fracture studies that used time-to-event methods to evaluate the effects of treatment on fracture risk, thereby allowing both the occurrence and the timing of fractures to be considered. METHODS: We used individual patient data (IPD) and time-to-event methods to perform a meta-analysis of the anti-fracture efficacy of risedronate (2.5 or 5 mg daily) in osteoporotic women enrolled in five double-blind, placebo-controlled clinical trials. Women were included in the analysis if, at baseline, they had either at least one prevalent vertebral fracture or a femoral neck bone mineral density (BMD) T-score of less than -2.5, were at least 1 year post-menopausal, and had had vertebral fracture assessments (N = 3331). RESULTS: Risedronate 5 mg daily reduced the risk of radiographically defined vertebral fracture by 64% (95% CI, 46 to 76%, p < 0.001) in the first year of treatment and 45% (95% CI, 31 to 57%, p < 0.001) in 3 years. The numbers of patients who needed to be treated with risedronate 5 mg to prevent one new vertebral fracture over 1 and 3 years were 21 and 13, respectively. Comparable findings were observed in sub-populations defined on the basis of either prevalent vertebral fracture without regard to femoral neck BMD, or femoral neck BMD without regard to vertebral fracture status. Risedronate significantly reduced the incidence of clinical (symptomatic) vertebral fractures in the first 6 months of treatment (p < 0.001). CONCLUSIONS: This meta-analysis, based upon five trials and using IPD and time-to-event statistical methods, provides a more precise estimate of the effect of risedronate in reducing vertebral fracture risk in postmenopausal osteoporotic women than a meta-analysis using summary statistics from the literature.

Bone Density↗

PubMed2001

Forced displacement in Yugoslavia: a meta-analysis of psychological consequences and their moderators.

A meta-analysis was conducted to synthesize what is known about differences in mental health between refugees and nonrefugees from the former Yugoslavia. The analysis focused on moderating effects of a variety of enduring, contextual stressors. Results indicated that refugees suffer significantly more mental health impairment than nonrefugees. The psychological consequences of forced displacement were found to vary significantly as a function of chronic stressors (e.g., locus of displacement and type of accommodation in exile) and were also associated with otherfactors (e.g., degree of war exposure in the nondisplaced groups, participant age, and time of data collection as reflected in year of publication). Implications for the study of refugee mental health are discussed.

Adult↗

PubMed2002

Recognition memory and decision processes: a meta-analysis of remember, know, and guess responses.

A meta-analysis of proportions of remember, know, and guess responses was carried out on observations from 86 experimental conditions in 23 different recognition memory experiments. Unlike remember and know responses, guess responses revealed no memory for the test items that elicited them. A signal detection analysis of these data showed that A' estimates of the strength of the memory trace depended on response criteria. A' estimates increased significantly when know responses were added to remember responses, and decreased significantly when guess responses were added to remember and know responses. It was guessing, rather than knowing, that was most strongly correlated with overall response criteria. Nor were remembering and knowing correlated significantly. These results do not support a quantitative trace strength model according to which these responses merely reflect different response criteria. They support theories that ascribe remembering and knowing to qualitatively distinct memory systems or processes.

Cognition↗

PubMed1998

A meta-analysis of clinical outcomes in the treatment of aphasia.

An extensive search of aphasia-treatment literature yielded 55 reports of clinical outcomes satisfying the essential criteria for inclusion in a meta-analysis. The results confirmed those of an earlier meta-analysis in demonstrating the utility of aphasia treatments, generally considered, for bringing about desirable clinical outcomes. Beyond the general case, the new findings address clinical utility in finer detail than was previously possible. Effects of treatment for aphasia are synthesized and assessed for each of four important dimensions: amount of treatment, type of treatment, severity of aphasia, and type of aphasia.

Acute Disease↗

PubMed1997

Are the clinical effects of homeopathy placebo effects? A meta-analysis of placebo-controlled trials.

BACKGROUND: Homeopathy seems scientifically implausible, but has widespread use. We aimed to assess whether the clinical effect reported in randomised controlled trials of homeopathic remedies is equivalent to that reported for placebo. METHODS: We sought studies from computerised bibliographies and contracts with researchers, institutions, manufacturers, individual collectors, homeopathic conference proceedings, and books. We included all languages. Double-blind and/or randomised placebo-controlled trials of clinical conditions were considered. Our review of 185 trials identified 119 that met the inclusion criteria. 89 had adequate data for meta-analysis, and two sets of trial were used to assess reproducibility. Two reviewers assessed study quality with two scales and extracted data for information on clinical condition, homeopathy type, dilution, "remedy", population, and outcomes. FINDINGS: The combined odds ratio for the 89 studies entered into the main meta-analysis was 2.45 (95% CI 2.05, 2.93) in favour of homeopathy. The odds ratio for the 26 good-quality studies was 1.66 (1.33, 2.08), and that corrected for publication bias was 1.78 (1.03, 3.10). Four studies on the effects of a single remedy on seasonal allergies had a pooled odds ratio for ocular symptoms at 4 weeks of 2.03 (1.51, 2.74). Five studies on postoperative ileus had a pooled mean effect-size-difference of -0.22 standard deviations (95% CI -0.36, -0.09) for flatus, and -0.18 SDs (-0.33, -0.03) for stool (both p < 0.05). INTERPRETATION: The results of our meta-analysis are not compatible with the hypothesis that the clinical effects of homeopathy are completely due to placebo. However, we found insufficient evidence from these studies that homeopathy is clearly efficacious for any single clinical condition. Further research on homeopathy is warranted provided it is rigorous and systematic.

Double-Blind Method↗

PubMed2005

An updated meta-analysis approach for genetic linkage.

We present a meta-analysis procedure for genome-wide linkage studies (MAGS). The MAGS procedure combines genome-wide linkage results across studies with possibly distinct marker maps. We applied the MAGS procedure to the simulated data from the Genetic Analysis Workshop 14 in order to investigate power to detect linkage to disease genes and power to detect linkage to disease modifier genes while controlling for type I error. We analyzed all 100 replicates of the four simulated studies for chromosomes 1 (disease gene), 2 (modifier gene), 3 (disease gene), 4 (no disease gene), 5 (disease gene), and 10 (modifier gene) with knowledge of the simulated disease gene locations. We found that the procedure correctly identified the disease loci on chromosomes 1, 3, and 5 and did not erroneously identify a linkage signal on chromosome 4. The MAGS procedure provided little to no evidence of linkage to the disease modifier genes on chromosomes 2 and 10.

Chromosomes, Human↗

PubMed2006

Association between bone density and fractures in children: a systematic review and meta-analysis.

OBJECTIVE: The objective of this article was to systematically review all published studies that investigated the association between bone density and fractures in children. DESIGN: Potentially relevant articles were identified by searching electronic databases. Duplicates were removed, abstracts were inspected, and relevant articles were obtained. Studies were included in the systematic review if participants were <16.0 years old, were healthy, had extractable data on bone mass, and had fractures as the outcome. RESULTS: Ten case-control studies were identified. No prospective studies were found. There was no evidence of heterogeneity between studies or of funnel-plot asymmetry. Eight of the studies were included in the meta-analysis, because they presented results as means and standard deviations of bone density in cases and controls. The pooled standardized mean difference for bone mass in children with and without fractures, from a fixed-effects model, was -0.32 (95% confidence interval: -0.43 to -0.21). CONCLUSIONS: Evidence for an association between bone density and fractures in children is limited. The results from this meta-analysis suggest that there is an association between low bone density and fractures in children. Although there was no evidence of heterogeneity or publication bias, this meta-analysis is based on case-control studies that are prone to bias. Large, well-conducted prospective cohort studies are required to confirm the association between bone density and fractures in children.

Bone Density↗

PubMed2004

[Eradication of Helicobacter pylori infection in Europe: a meta-analysis based on congress abstracts, 1997-2002].

BACKGROUND: Meta-analyses evaluated several aspects of Helicobacter pylori eradication based on the randomised controlled trials. AIM: to perform a meta-analysis of the papers presented at the European Helicobacter Pylori Study Group and United European Gastroenterology Week meetings from 1997 to 2002. METHODS: Abstracts dealing with the eradication of Helicobacter pylori have been reviewed and the randomised, controlled studies from European countries were included. The studies were classified into groups based on eradication schedules, antibiotics used and country of provenience. The pooled eradication rates were calculated and the differences were assessed by multiple variance analysis. RESULTS: One-hundred and two studies were accepted comprising 25,644 cases and 398 treatment arms. The eradication rate of proton pump inhibitor-based first line triple therapies was 80.4% (confidence interval: 78.9-81.8); no difference was observed between the five proton pump inhibitors (p > 0.05). Ranitidine bismuth citrate based regimens were efficient in 79.9% (75.7-84.0) (p = 0.95 vs PPI). H2 blockers-based therapies achieved 68.6% (59.0-78.1) (p = 0.0007 vs proton pump inhibitor and p = 0.005 vs ranitidine bismuth citrate-based regimens). Proton pump inhibitor-based double combinations were efficient in 47.1 (31.9-62.4) (p = 0.001 vs triple regimens). Clarithromycin+amoxicillin/nitroimidazole combinations achieved rates of 79.6% and 84.1%, respectively, while amoxicillin-nitroimidazole regimens were less efficient (72.5%, 66.6-78.5) (p = 0.006). The pooled eradication rate of second-line triple regimens was 75.5% (69.9-86.4)(p = 0.08 vs primary treatment). Quadruple therapies were successful in 81.1% (76.6-85.6) of cases as first-line and 73.8% (61.2-86.4) as second-line regimens (p = 0.77 and p = 0.02 vs triple regimens). The pooled eradication rates varied from 58% to 92% in the European countries. CONCLUSIONS: The pooled eradication rate of the primary proton pump inhibitor/ranitidine bismuth citrate-based triple regimens are comparable with the results of meta-analyses. H2 blocker-based triple and proton pump inhibitor-based double regimens are of lower efficacy. Quadruple regimens were not better than triple therapies. The eradication rates per country varied, approaching 80% in most places. The results confirm in part post-hoc the validity of the Maastricht consensus recommendations.

Amoxicillin↗

PubMed1993

A meta-analysis of treatments for panic disorder.

In a meta-analysis, the authors compared the effectiveness of psychological and pharmacological treatments for panic disorder. Percentage of agoraphobic subjects in the sample and duration of the illness were unrelated to effect size (ES). Type of dependent variable was generally unrelated to treatment outcome, although behavioral measures yielded significantly smaller ESs. Dependent measures of general anxiety, avoidance, and panic attacks yielded larger ESs than did depression measures. Choice of control was related to ES, with comparisons with placebo controls greater than comparisons with exposure-only or "other treatment" controls. Psychological coping strategies involving relaxation training, cognitive restructuring, and exposure yielded the most consistent ESs; flooding and combination treatments (psychological and pharmacological) yielded the next most consistent ESs. Antidepressants were the most effective pharmacological intervention.

Agoraphobia↗

PubMed2003

Cesarean delivery for twins: a systematic review and meta-analysis.

OBJECTIVE: We undertook a systematic review and meta-analysis to determine whether a policy of planned cesarean section or vaginal delivery is better for twins. STUDY DESIGN: We searched MEDLINE and EMBASE from 1980 through May 2001 using combinations of the following terms: twin, delivery, cesarean section, vaginal birth, birth weight, and gestational age. Studies that compared planned cesarean section to planned vaginal birth for babies weighing at least 1500 g or reaching at least 32 weeks' gestation were included. We computed pooled odds ratios for perinatal or neonatal mortality, low 5-minute Apgar score, neonatal morbidity, and maternal morbidity. The infant was the unit of statistical analysis. Results were considered statistically significant if the 95% CI did not encompass 1.0. RESULTS: We retrieved 67 articles, 63 of which were excluded. Four studies with a total of 1932 infants were included in the analysis. A low 5-minute Apgar score occurred less frequently in twins delivered by planned cesarean section (odds ratio, 0.47; 95% CI, 0.26-0.88) principally because of a reduction among twins if twin A was in breech position (odds ratio, 0.33; 95% CI, 0.17-0.65). Twins delivered by planned cesarean section spent significantly longer in the hospital (mean difference, 4.01 days; 95% CI, 0.73-7.28 days). There were no significant differences in perinatal or neonatal mortality, neonatal morbidity, or maternal morbidity. CONCLUSION: Planned cesarean section may decrease the risk of a low 5-minute Apgar score, particularly if twin A is breech. Otherwise, there is no evidence to support planned cesarean section for twins.

Apgar Score↗

PubMed2005

Parents' psychological adjustment in families of children with spina bifida: a meta-analysis.

BACKGROUND: Spina Bifida (SB) is the second most common birth defect worldwide. Since the chances of survival in children with severe SB-forms have increased, medical care has shifted its emphasis from life-saving interventions to fostering the quality of life for these children and their families. Little is known, however, about the impact of SB on family adjustment. Reviewers have struggled to synthesize the few contradictory studies available. In this systematic review a new attempt was made to summarize the findings by using meta-analysis and by delimiting the scope of review to one concept of family adjustment: Parents' psychological adjustment. The questions addressed were: (a) do parents of children with SB have more psychological distress than controls? (b) do mothers and fathers differ? and (c) which factors correlate with variations in psychological adjustment? METHODS: PsycInfo, Medline, and reference lists were scanned. Thirty-three relevant studies were identified of which 15 were eligible for meta-analysis. RESULTS: SB had a negative medium-large effect on parents' psychological adjustment. The effect was more heterogeneous for mothers than for fathers. In the reviewed studies child factors (age, conduct problems, emotional problems, and mental retardation), parent factors (SES, hope, appraised stress, coping, and parenting competence), family factors (family income, partner relationship, and family climate), and environmental factors (social support) were found to be associated with variations in parents' psychological adjustment. CONCLUSION: Meta-analysis proved to be helpful in organizing studies. Clinical implications indicate a need to be especially alert to psychological suffering in mothers of children with SB. Future research should increase sample sizes through multi-center collaborations.

Adaptation, Psychological↗

PubMed2006

Forming attitudes that predict future behavior: a meta-analysis of the attitude-behavior relation.

A meta-analysis (k of conditions = 128; N = 4,598) examined the influence of factors present at the time an attitude is formed on the degree to which this attitude guides future behavior. The findings indicated that attitudes correlated with a future behavior more strongly when they were easy to recall (accessible) and stable over time. Because of increased accessibility, attitudes more strongly predicted future behavior when participants had direct experience with the attitude object and reported their attitudes frequently. Because of the resulting attitude stability, the attitude-behavior association was strongest when attitudes were confident, when participants formed their attitude on the basis of behavior-relevant information, and when they received or were induced to think about one- rather than two-sided information about the attitude object.

Attitude↗

PubMed1992

A meta-analysis of antidepressant outcome under "blinder" conditions.

A meta-analysis of 22 studies of antidepressant outcome assessed the level of medication effects under conditions thought to be less subject to clinician bias than those in the typical double-blind drug trial. Studies were included only if, in addition to a newer antidepressant group, they also contained both standard antidepressant and placebo control groups. Effect sizes were quite modest and approximately one half to one quarter the size of those previously reported under more transparent conditions. Effect sizes that were based on clinician outcome ratings were significantly larger than those that were based on patient ratings. Patient ratings revealed no advantage for antidepressants beyond the placebo effect. Effect sizes were unrelated to sample sex ratios, patient age, inpatient or outpatient status, dosage level, and treatment duration. Findings highlight the fragility of the antidepressant effect.

Antidepressive Agents↗

PubMed2001

Using Bayesian inference to perform meta-analysis.

Bayesian modeling offers an elegant approach to meta-analysis that efficiently incorporates all sources of variability and relevant quantifiable external information. It provides a more informative summary of the likely value of parameters after observing the data than do non-Bayesian approaches. This leads to direct probabilistic inference about model parameters such as the average treatment effect, the between-study variance, and individual study treatment effects. The latter are weighted averages of the common mean and individual study means with weights reflecting the amount of information provided by each study relative to the others. Homogeneity among these posterior study estimates indicates that pooling these studies is appropriate; heterogeneity suggests that some cause of between-study variation should be explored. The author describes the construction of such models and shows how to use them to estimate a common mean and regression slopes. Two examples illustrate the additional inferences available with the Bayesian methodology.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2002

African-American ethnicity, socioeconomic status, and breast cancer survival: a meta-analysis of 14 studies involving over 10,000 African-American and 40,000 White American patients with carcinoma of the breast.

BACKGROUND: African-American women are at increased risk for breast cancer mortality compared with white American women, and the extent to which socioeconomic factors account for this outcome disparity is unclear. METHODS: A MEDLINE search was conducted to identify published studies that used a Cox proportional hazards regression model to evaluate the outcome of African-American women and white American women with breast carcinoma after adjusting for socioeconomic status. A meta-analysis was performed using specialized statistical software; the random-effects method of statistical evaluation was used because of the a priori impression that the studies reviewed would be at least moderately heterogeneous in study design and patient populations. RESULTS: The initial literature search yielded 3962 studies. Fourteen studies met all criteria for inclusion in the meta-analysis, resulting in a sample size of 10,001 African-American patients and 42,473 white American patients with breast carcinoma. There was substantial variation in the method used for defining socioeconomic status. Summary statistics revealed a significant odds ratio of 1.22 (95% confidence interval, 1.13-1.30) for the adverse effect of African-American ethnicity on breast cancer mortality. Subset meta-analyses yielded similar results, supporting the robustness of this finding. CONCLUSIONS: This meta-analysis revealed that African-American ethnicity is an independent predictor of a worse breast cancer outcome. The pooled analysis has added strength because of the aggregate sample size and indicates that the true biologic and/or therapeutic determinants of disparities in breast cancer outcome for different ethnic groups and for different socioeconomic strata are incompletely understood.

Adult↗

PubMed2006

The role of aminoglycosides in combination with a beta-lactam for the treatment of bacterial endocarditis: a meta-analysis of comparative trials.

BACKGROUND: The addition of an aminoglycoside to a beta-lactam for the treatment of patients with infective endocarditis has been supported by data from laboratory and animal studies. PURPOSE: We sought to review the evidence from the available comparative clinical trials regarding the role of aminoglycosides in combination with a beta-lactam for the treatment of bacterial endocarditis caused by Gram-positive cocci. DATA SOURCES: The studies for our meta-analysis were retrieved from searches of the PubMed and Cochrane Central Register of Controlled Trials databases, as well as from the references cited in relevant articles. No limits were set regarding the language and date of publication of the studies. STUDY SELECTION: Included studies were prospective studies that provided comparative data regarding the effectiveness of the treatment and/or mortality in patients receiving monotherapy with a beta-lactam or beta-lactam/aminoglycoside combination therapy. DATA EXTRACTION: Two independent reviewers performed the literature search, study selection and extraction of data from relevant studies. DATA SYNTHESIS: No clinical trial comparing beta-lactam monotherapy with beta-lactam/aminoglycoside combination therapy for the treatment of enterococcal endocarditis was found. We performed a meta-analysis of five available comparative trials [four randomized controlled trials (RCTs) and one comparative prospective trial], which included 261 patients with bacterial endocarditis in native valves due to Staphylococcus aureus (four studies) or streptococci of the viridans group (one study). There was no statistically significant difference between beta-lactam monotherapy and beta-lactam/aminoglycoside combination therapy regarding mortality [odds ratio (OR) = 0.59, 95% confidence interval (95% CI) = 0.21-1.66], treatment success (OR = 1.25, 95% CI = 0.49-3.05), treatment success without surgery (OR = 1.66, 95% CI = 0.64-4.30) or relapse of endocarditis (OR = 0.79, 95% CI = 0.15-4.29). Nephrotoxicity was less common in the beta-lactam monotherapy arm than in the beta-lactam/aminoglycoside combination therapy arm (OR = 0.38, 95% CI = 0.16-0.88, P = 0.024). No difference between the two treatment arms was found in subanalyses of the four studies that included only patients with staphylococcal infections in terms of mortality (OR = 0.69, 95% CI = 0.26-1.86, fixed effects model), treatment success (OR = 1.27, 95% CI = 0.47-3.43, fixed effects model) or relapse (OR = 0.76, 95% CI = 0.12-4.92, fixed effects model). LIMITATIONS: The relatively small number of available comparative trials was the major limitation of this meta-analysis. CONCLUSIONS: The limited evidence from the available prospective comparative studies does not offer support for the addition of an aminoglycoside to beta-lactam treatment of patients with endocarditis caused by Gram-positive cocci. A large multicentre RCT is necessary to reach a definitive conclusion on this issue.

Aminoglycosides↗

PubMed2006

Succinylcholine or rocuronium? A meta-analysis of the effects on intubation conditions.

This meta-analysis was undertaken to compare the effects of succinylcholine (SCH) and rocuronium (RCR) on endotracheal intubation (ETI) conditions. Eligible randomised controlled trials (RCTs) were identified via medline and a manual search of references. The frequencies of excellent and unacceptable ETI conditions in subjects receiving SCH 1.0-1.5 mg/kg and RCR 0.6-1.2 mg/kg were determined using standard statistical methods. Inclusion criteria were met by 16 RCTs, representing 1362 subjects. SCH was associated with a 17.7% increase (95% CI = 13-22) in the frequency of excellent ETI conditions and a 5.1% decrease (95% CI = -7.3 to -2.9) in the frequency of unacceptable ETI conditions, when compared with RCR. In the subgroup undergoing true rapid sequence intubation, SCH was associated with a 19.1% increase (95% CI = 13.7-24.5) in the frequency of excellent ETI conditions. SCH appears to be superior to RCR in creating excellent ETI conditions and avoiding unacceptable ETI conditions.

Androstanols↗

PubMed2005

Non-invasive brain stimulation for Parkinson's disease: a systematic review and meta-analysis of the literature.

A systematic review and meta-analysis were conducted to quantify the efficacy of transcranial magnetic stimulation (TMS) and electroconvulsive therapy (ECT) for the treatment of motor dysfunction in patients with Parkinson's disease (PD). Prospective studies which evaluated the effects of either TMS (12 studies) or ECT (five studies) on motor function in PD using the motor subscale of the Unified Parkinson's Disease Rating Scale (UPDRS) for TMS studies and any continuous measures of motor function in PD for ECT studies were included. The pooled effect size (standardised mean difference between pre-treatment versus post-treatment means) from a random effects model was 0.62 (95% confidence interval: 0.38, 0.85) for TMS treatment and 1.68 (0.79, 2.56) for ECT treatment, and from a fixed effects model was 0.59 (0.39, 0.78) for TMS treatment and 1.55 (1.07, 2.03) for ECT treatment. TMS, across applied stimulation sites and parameters, can exert a significant, albeit modest, positive effect on the motor function of patients with PD. ECT also may exert a significant effect on motor function in PD patients.

Electroconvulsive Therapy↗