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Random-effects Meta-analysis (random-effect + meta-analysi)
Selected AbstractsOutcome of primary root canal treatment: systematic review of the literature , Part 2.INTERNATIONAL ENDODONTIC JOURNAL, Issue 1 2008Influence of clinical factors Abstract Aims, (i) To carry out meta-analyses to quantify the influence of the clinical factors on the efficacy of primary root canal treatment and (ii) to identify the best treatment protocol based on the current evidence. Methodology, The evidence for the effect of each clinical factor on the success rate (SR) of primary root canal treatment was gathered in three different ways: (i) intuitive synthesis of reported findings from individual studies; (ii) weighted pooled SR by each factor under investigation was estimated using random-effect meta-analysis; (iii) weighted effect of the factor under investigation on SR were estimated and expressed as odds ratio for the dichotomous outcomes (success or failure) using fixed- and random-effects meta-analysis. Statistical heterogeneity amongst the studies was assessed by Cochran's (Q) test. Potential sources of statistical heterogeneity were investigated by exploring clinical heterogeneity using meta-regression models which included study characteristics in the regression models. Results, Out of the clinical factors investigated, pre-operative pulpal and periapical status were most frequently investigated, whilst the intra-operative factors were poorly studied in the 63 studies. Four factors were found to have a significant effect on the primary root canal treatment outcome, although the data heterogeneity was substantial, some of which could be explained by some of the study characteristics. Conclusions, Four conditions (pre-operative absence of periapical radiolucency, root filling with no voids, root filling extending to 2 mm within the radiographic apex and satisfactory coronal restoration) were found to improve the outcome of primary root canal treatment significantly. Root canal treatment should therefore aim at achieving and maintaining access to apical anatomy during chemo-mechanical debridement, obturating the canal with densely compacted material to the apical terminus without extrusion into the apical tissues and preventing re-infection with a good quality coronal restoration. [source] Effects of reminiscence and life review on late-life depression: a meta-analysisINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 12 2003Ernst Bohlmeijer Abstract Aim To assess the effectiveness of reminiscence and life review on late-life depression across different target groups and treatment modalities. Method Twenty controlled outcome studies were retrieved from Psychlit, Medline and Dissertation Abstracts. For each study a standardised effect size, d, was calculated and a random-effects meta-analysis was conducted. Results An overall effect size of 0.84 (95% Confidence Intervals (CI)=0.31,1.37) was found, indicating a statistically and clinically significant effect of reminiscence and life review on depressive symptomatology in elderly people. This effect is comparable to the effects commonly found for pharmacotherapy and psychological treatments. The effect was larger in subjects with elevated depressive symptomatology (d=1.23) as compared to other subjects (d=0.37). Other characteristics of the subjects or interventions were not found to be related to increased or decreased effect sizes. Discussion Reminiscence and life review are potentially effective treatments for depressive symptoms in the elderly and may thus offer a valuable alternative to psychotherapy or pharmacotherapy. Especially in non-institutionalised elderly people,who often have untreated depression,it may prove to be an effective, safe and acceptable form of treatment. Randomized trials with sufficient statistical power are necessary to confirm the results of this study. Copyright © 2003 John Wiley & Sons, Ltd. [source] Sensitivity of superficial cultures in lower extremity wounds,JOURNAL OF HOSPITAL MEDICINE, Issue 7 2010Chayan Chakraborti MD Abstract BACKGROUND: Superficial wound cultures are routinely used to guide therapy, despite a lack of clear supporting evidence. PURPOSE: To conduct a systematic review of the correlation between superficial wound cultures and the etiology of skin and soft tissue infections. DATA SOURCES: Medline, EMBASE, CINAHL, Scopus. STUDY SELECTION: Articles published between January 1960 and August 2009 involving superficial wound cultures and deeper comparison cultures. DATA EXTRACTION: Two reviewers independently searched for abstracted information pertaining to the microbiology of lower extremity wounds sufficient to calculate the sensitivity and specificity of superficial wound cultures versus comparison cultures. DATA SYNTHESIS: Data pooled using a random-effects meta-analysis model. RESULTS: Of 9032 unique citations, 8 studies met all inclusion criteria. Inter-rater reliability was substantial (Kappa = 0.78). Pooled test sensitivity for superficial wound swabs was 49% (95% confidence interval [CI], 37-61%], and specificity was 62% (95% CI, 51-74%). The pooled positive and negative likelihood ratios (LRs) were 1.1 (95% CI, 0.71-1.5) and 0.67 (95% CI, 0.52-0.82). The median number of isolates for surface cultures (2.7, interquartile range [IQR] 1.8-3.2) was not significantly different than that for comparison cultures, (2.2, IQR 1.7-2.9) (P = 0.75). CONCLUSION: Few studies show a strong relationship between superficial wound swabs and deep tissue cultures, and the current data demonstrate poor overall sensitivity and specificity. The positive and negative LRs were found to provide minimal utility in influencing pretest probabilities. Results of this analysis show that wound cultures should not be used in lieu of local antibiograms to guide initial antibiotic therapies. Journal of Hospital Medicine 2010;5:415,420. © 2010 Society of Hospital Medicine. [source] A re-evaluation of random-effects meta-analysisJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 1 2009Julian P. T. Higgins Summary., Meta-analysis in the presence of unexplained heterogeneity is frequently undertaken by using a random-effects model, in which the effects underlying different studies are assumed to be drawn from a normal distribution. Here we discuss the justification and interpretation of such models, by addressing in turn the aims of estimation, prediction and hypothesis testing. A particular issue that we consider is the distinction between inference on the mean of the random-effects distribution and inference on the whole distribution. We suggest that random-effects meta-analyses as currently conducted often fail to provide the key results, and we investigate the extent to which distribution-free, classical and Bayesian approaches can provide satisfactory methods. We conclude that the Bayesian approach has the advantage of naturally allowing for full uncertainty, especially for prediction. However, it is not without problems, including computational intensity and sensitivity to a priori judgements. We propose a simple prediction interval for classical meta-analysis and offer extensions to standard practice of Bayesian meta-analysis, making use of an example of studies of ,set shifting' ability in people with eating disorders. [source] Meta-analysis of digit ratio 2D:4D shows greater sex difference in the right handAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2010Johannes Hönekopp Objectives: Our aims are, first, to describe the sex difference in the length ratio of the second and fourth digits (2D:4D), which likely reflects prenatal testosterone levels in humans. Second, to infer the loss of reliability observed in 2D:4D based on self-measured finger lengths. Methods: We used random-effects meta-analysis of 2D:4D based on expert-measured finger lengths (116 samples with 13,260 females and 11,789 males). Results: We find a moderate sex difference (with lower 2D:4D for males), which shows substantial heterogeneity (which is unrelated to age). The sex difference is moderated by the type of finger length measurement and by hand. Measurement involving the distortion of soft tissue leads to a significantly larger sex difference than finger length measurement avoiding this. The sex difference in 2D:4D is larger in the right hand than in the left. The reliability of self-measured 2D:4D in the BBC internet study, by far the largest study on 2D:4D, is estimated to be 46% of that of expert-measured 2D:4D. Conclusions: Right-hand 2D:4D might be a better indicator of prenatal androgenisation than left-hand 2D:4D. The view that 2D:4D has allometric properties (Kratochvil L, Flegr J. 2009. Differences in 2nd to 4th digit length ratio in humans reflect shifts along the common allometric line. Biol Lett 5:643,646.) is not supported. Bone lengths contribute to the sex difference in 2D:4D. In addition, there might be a sex difference in fingers' soft tissue, which should be investigated. Because of measurement unreliability, correlations between 2D:4D and variables of interest are about one-third smaller in the BBC internet study than in studies in which 2D:4D is based on expert-measured finger lengths. Am. J. Hum. Biol. 22:619,630, 2010. © 2010 Wiley-Liss, Inc. [source] Updated meta-analysis of clinical trials of Serenoa repens extract in the treatment of symptomatic benign prostatic hyperplasiaBJU INTERNATIONAL, Issue 6 2004P. Boyle OBJECTIVES To determine, by analysing all available clinical trial data, the clinical efficacy against placebo of an extract from the fruit of the American dwarf palm tree, Serenoa repens (Permixon®, Pierre Fabre Médicament, Castres, France), as there is controversy about the use of phytotherapeutic agents in men with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH). METHODS All clinical trial data published on Permixon, comprising 14 randomized clinical trials and three open-label trials, involving 4280 patients, were analysed. These trials were of different size (22,1100 patients) and duration (21,720 days). The peak urinary flow rate and nocturia were the two common endpoints. The statistical analysis was based on a random-effects meta-analysis. RESULTS Permixon was associated with a mean (sem) reduction in the International Prostate Symptom Score (IPSS) of 4.78 (0.41). The mean placebo effect on peak urinary flow rate was an increase of 1.20 (0.49) mL/s. The estimated effect of Permixon was a further increase of 1.02 (0.50) mL/s (P = 0.042). Placebo was associated with a reduction in the mean number of nocturnal voids of 0.63 (0.14); there was a further reduction attributable to Permixon of 0.38 (0.07) (P < 0.001). There was some heterogeneity among the studies for nocturia; one over 2 years involving 396 patients and showing no difference between placebo and Permixon had a large effect on the results. CONCLUSIONS This meta-analysis of all available published trials of Permixon for treating men with BPH showed a significant improvement in peak flow rate and reduction in nocturia above placebo, and a 5-point reduction in the IPSS. [source] Comparison of the effects of treatment of peri-implant infection in animal and human studies: systematic review and meta-analysisCLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2010Clovis Mariano Faggion Jr Abstract Objective: The main objective of this systematic review is to compare the effects of treatment of peri-implant infection between animal and human studies. Material and methods: A literature search was conducted using the Medline, Cochrane Central Register of Controlled Trials, and Latin American and Caribbean Health Sciences Literature databases up to and including May 2008. In addition, bibliographies of systematic reviews on peri-implant diseases were searched manually. Non-surgical and surgical treatments of peri-implantitis/mucositis in animal models or human studies were compared. Meta-analysis was conducted to investigate the difference between the reported treatment effects in animal and human studies. Changes in probing pocket depth (PPD) and probing attachment level (PAL) from baseline measurements were used as measures of outcome. Single-level and multilevel meta-regression analysis was performed by taking into account the different follow-up times of the studies included. Results: The single-level and multilevel random-effects meta-analysis showed that the difference in PPD reduction [0.31 mm, 95% confidence interval (CI): ,0.27, 0.88] and in PAL gain (0.21 mm, 95% CI: ,0.47, 0.88) between animal and human studies was not statistically significant. The random-effects meta-regression suggested that studies with longer follow-up times revealed greater PPD reduction (0.25 mm per month, 95% CI: 0.14, 0.35). However, when the different follow-up times were taken into account, these differences became greater. Substantial heterogeneity between studies was found in the meta-analyses (I2=97.6% for animal studies and 99.9% for human studies). Conclusion: There was great heterogeneity between human and animal studies in terms of study designs and treatment procedures. Therefore, the results from this meta-analysis should be interpreted with caution. Heterogeneity between studies and its causes merit further investigations. To cite this article: Faggion CM Jr, Chambrone L, Gondim V, Schmitter M, Tu Y-K. Comparison of the effects of treatment of peri-implant infection in animal and human studies: systematic review and meta-analysis. Clin. Oral Impl. Res. 21, 2010; 137,147. doi: 10.1111/j.1600-0501.2009.01753.x [source] | ||||||||||