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With many different operative techniques in use to reduce the incidence of incisional hernias (IH) following a midline laparotomy, there is no consensus among the clinicians on the efficacy and safety of any particular repair technique. This meta-analysis compares the prophylactic onlay mesh repair (POMR) and primary suture repair (PSR) for the incidence of IH. A meta-analysis and systematic review of MEDLINE, PubMed Central (via PubMed), Embase (via Ovid), SCOPUS, ScienceDirect, Google Scholar, SCI and Cochrane Library databases were undertaken. Seven randomized controlled trials assessing the outcomes of PSR and POMR were analyzed in accordance with the PRISMA statement. The risk of bias was assessed using the Rob2 tool. According to the pooled analysis, POMR significantly reduced the incidence of IH compared to the PSR (OR 5.82 [95% CI 2.69, 12.58] P

Meta-analysis has become an integral part of evidence-based decision-making processes and is being increasingly used in medical and non-medical disciplines. Aggregate data or summary statistics continue to be the mainstay of meta-analysis and are used by many professional societies to support clinical practice guidelines. Meta-analyses synthesize the summary statistics from independent trials by pooling them to estimate the underlying common effect size. The results represent the highest level of evidence but only if the chosen studies are of high quality and the selection criteria are fully satisfied. It is important to address the issues of defining an explicit and relevant question, exhaustively searching for the totality of evidence, meticulous and unbiased data transfer or extraction, assessment of between study heterogeneity and the use of appropriate statistical methods for estimating summary effect measures. This article reviews the methodology, benefits and drawbacks of performing a meta-analysis.

Development and implementation of advanced statistical models for analyzing stochastic dependencies of systemic weather risk can help farmers, agricultural policy-makers and financial agents to address potential risk adaptation strategies and mitigation of threats to the agricultural industry. This study develops copula-based statistical models to provide a better understanding of systemic weather risks with agricultural and weather event data from Australia. In particular, we adopt a C-vine approach to model the joint insurance losses caused by drought events occurring simultaneously across different locations, and consecutively in different growing seasons. This modelling approach is enriched by a clustering analysis process through the multidimensional Kruskal–Shephard scaling method. Daily rainfall data (1889–2012) recorded in sixteen meteorological stations across Australia’s wheat belt spanning different climatic conditions are employed. On a regional scale, droughts occurring in the west are more scattered during the October–December period and for April–June and October–December in the eastern, south-eastern and southern regions. On a national scale, drought events in the east are likely to spread out to the south-east and the south but not to the west. The results also reveal that the drought events in different seasons may not be perfectly correlated. Therefore, we conclude that spatial and temporal diversification strategies are likely to feasibly reduce the systemic weather risk in Australia. In particular, the average risk-reducing effect of the entire insured area across regional, national and temporal scales ranges between 0.62–0.94, 0.48–0.76, and 0.25–0.33, corresponding to 5%- (extreme drought) and 25%-quantiles (moderate drought). The findings suggest that diversifying risks over time is potentially more effective than spatial diversification. The outcomes may also act as an efficient tool for agricultural risk reduction, but simultaneously, it may also provide immensely useful information for suitable pricing of weather index-based insurance products.

Twelve large-scale climate drivers are employed to investigate their spatio-temporal influence on the variability of seasonal wheat yield in five major wheat-producing states across Australia using data for the period 1983–2013. Generally, the fluctuations in the Indian Ocean appear to have a dominant effect on the Australian wheat crop in all states except Western Australia, while the impact of oceanic conditions in the Pacific region is much stronger in Queensland. The results show a statistically significant negative correlation between the Indian Ocean Dipole (IOD) and the anomalous wheat yield in the early growing stage of the crop in the eastern and southeastern wheat belt regions. This correlation suggests that the wheat yield can be skillfully forecast 3–6 months ahead, supporting early decision-making in regard to precision agriculture. In this study, we use vine copula models to capture climate-yield dependence structures, including the occurrence of extreme events (i.e., the tail dependences). The co-occurrence of extreme events is likely to enhance the impacts of climate mode and this can be quantified probabilistically through conditional copula-based models. Generally, the developed D-vine quantile regression model provide greater accuracy for the forecasting of wheat yield at given different confidence levels compared to the traditional linear quantile regression (LQR) method. A five-fold cross-validation approach is also used to estimate the out-of-sample accuracy of both copula-statistical forecasting models. These findings provide a comprehensive analysis of the spatio-temporal impacts of different climate mode indices on Australian wheat crops. Improved quantification of the impacts of large-scale climate drivers on the wheat yield can allow a development of suitable planning processes and crop production strategies designed to optimize the yield and agricultural profit.

Vine copulas are employed to explore the influence of multi-synoptic-scale climate drivers – El Nino Southern Oscillation (ENSO) and Inter-decadal Pacific Oscillation (IPO) Tripole Index (TPI) – on spring precipitation forecasting at Agro-ecological Zones (AEZs) of the Australia’s wheat belt. To forecast spring precipitation, significant seasonal lagged correlation of ENSO and TPI with precipitation anomalies in AEZs using data from Australian Water Availability Project (1900–2013) was established. Most of the AEZs exhibit statistically significant dependence of precipitation and climate indices, except for the western AEZs. Bivariate and trivariate copula models were applied to capture single (ENSO) and dual predictor (ENSO & TPI) influence, respectively, on seasonal forecasting. To perform a comprehensive evaluation of the developed copula-statistical models, a total of ten one- and two-parameter bivariate copulas ranging from elliptical to Archimedean families were examined. Stronger upper tail dependence is visible in the bivariate model, suggesting that the influence of ENSO on precipitation forecasting during a La Nina event is more evident than during an El Nino event. In general, while the inclusion of TPI as a synoptic-scale driver into the models leads to a notable reduction in the mean simulated precipitation, it depicts a general improvement in the median values. The forecasting results showed that the trivariate forecasting model can yield a better accuracy than the bivariate model for the east and southeast AEZs. The trivariate forecasting model was found to improve the forecasting during the La Nina and negative TPI. This study ascertains the success of copula-statistical models for investigating the joint behaviour of seasonal precipitation modelled with multiple climate indices. The forecasting information and respective models have significant implications for water resources and crop health management including better ways to adapt and implement viable agricultural solutions in the face of climatic challenges in major agricultural hubs, such as Australia’s wheat belt.

Consider independent random samples from \((k\ge 2)\) Pareto populations with the same known shape parameter but different scale parameters. Let \(X_i\) be the smallest observation of the ith sample. The natural selection rule which selects the population associated with the largest \(X_i\) is considered. In this paper, we estimate the moments of the selected population under asymmetric scale invariant loss function. We investigate risk-unbiased, consistency and admissibility of the natural estimators for the moments of the selected population. Finally, the risk-bias’s and risks of the natural estimators are numerically computed and compared for \(k=2,3.\)

Laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic vertical sleeve gastrectomy (LVSG) have been proposed as cost-effective strategies to manage obesity-related chronic disease. The aim of this meta-analysis and systematic review was to compare the “early postoperative complication rate i.e. within 30-days” reported from randomized control trials (RCTs) comparing these two procedures. RCTs comparing the early complication rates following LVSG and LRYGB between 2000 and 2015 were selected from PubMed, Medline, Embase, Science Citation Index, Current Contents, and the Cochrane database. The outcome variables analyzed included 30-day mortality, major and minor complications and interventions required for their management, length of hospital stay, readmission rates, operating time, and conversions from laparoscopic to open procedures. Six RCTs involving a total of 695 patients (LVSG n = 347, LRYGB n = 348) reported on early major complications. A statistically significant reduction in relative odds of early major complications favoring the LVSG procedure was noted (p = 0.05). Five RCTs representing 633 patients (LVSG n = 317, LRYGB n = 316) reported early minor complications. A non-statically significant reduction in relative odds of 29 % favoring the LVSG procedure was observed for early minor complications (p = 0.4). However, other outcomes directly related to complications which included reoperation rates, readmission rate, and 30-day mortality rate showed comparable effect size for both surgical procedures. This meta-analysis and systematic review of RCTs suggests that fewer early major and minor complications are associated with LVSG compared with LRYGB procedure. However, this does not translate into higher readmission rate, reoperation rate, or 30-day mortality for either procedure.

This article examines an improved alternative to the random effects (RE) model for meta-analysis of heterogeneous studies. It is shown that the known issues of underestimation of the statistical error and spuriously overconfident estimates with the RE model can be resolved by the use of an estimator under the fixed effect model assumption with a quasi-likelihood based variance structure - the IVhet model. Extensive simulations confirm that this estimator retains a correct coverage probability and a lower observed variance than the RE model estimator, regardless of heterogeneity. When the proposed IVhet method is applied to the controversial meta-analysis of intravenous magnesium for the prevention of mortality after myocardial infarction, the pooled OR is 1.01 (95% CI 0.71-1.46) which not only favors the larger studies but also indicates more uncertainty around the point estimate. In comparison, under the RE model the pooled OR is 0.71 (95% CI 0.57-0.89) which, given the simulation results, reflects underestimation of the statistical error. Given the compelling evidence generated, we recommend that the IVhet model replace both the FE and RE models. To facilitate this, it has been implemented into free meta-analysis software called MetaXL which can be downloaded from www.epigear.com.

The utility of laparoscopic repair in the treatment of incisional hernia repair is still contentious.The aim was to conduct a meta-analysis of RCTs investigating the surgical and postsurgical outcomes of elective incisional hernia by open versus laparoscopic method.A search of PubMed, Medline, Embase, Science Citation Index, Current Contents, and the Cochrane Central Register of Controlled Trials published between January 1993 and September 2013 was performed using medical subject headings (MESH) "hernia," "incisional," "abdominal," "randomized/randomised controlled trial," "abdominal wall hernia," "laparoscopic repair," "open repair", "human" and "English".Prospective RCTs comparing surgical treatment of only incisional hernia (and not primary ventral hernias) using open and laparoscopic methods were selected.Data extraction and critical appraisal were carried out independently by two authors (AA and MAM) using predefined data fields. The outcome variables analyzed included (a) hernia diameter; (b) operative time; (c) length of hospital stay; (d) overall complication rate; (e) bowel complications; (f) reoperation; (g) wound infection; (h) wound hematoma or seroma; (i) time to oral intake; (j) back to work; (k) recurrence rate; and (l) postoperative neuralgia. These outcomes were unanimously decided to be important since they influence the practical and surgical approach towards hernia management within hospitals and institutions. The quality of RCTs was assessed using Jadad's scoring system. Random effects model was used to calculate the effect size of both binary and continuous data. Heterogeneity amongst the outcome variables of these trials was determined by the Cochran Q statistic and I (2) index. The meta-analysis was prepared in accordance with PRISMA guidelines.Sufficient data were available for the analysis of twelve clinically relevant outcomes. Statistically significant reduction in bowel complications was noted with open surgery compared to the laparoscopic repair in five studies (OR 2.56, 95 % CI 1.15, 5.72, p = 0.02). Comparable effects were noted for other variables which include hernia diameter (SMD -0.27, 95 % CI -0.77, 0.23, p = 0.29), operative time (SMD -0.08, 95 % CI -4.46, 4.30, p = 0.97), overall complications (OR -1.07, 95 % CI -0.33, 3.42, p = 0.91), wound infection (OR 0.49, 95 % CI 0.09, 2.67, p = 0.41), wound hematoma or seroma (OR 1.54, 95 % CI 0.58, 4.09, p = 0.38), reoperation rate (OR -0.32, 95 % CI 0.07, 1.43, p = 0.14), time to oral intake (SMD -0.16, 95 % CI -1.97, 2.28, p = 0.89), length of hospital stay (SMD -0.83, 95 % CI -2.22, 0.56, p = 0.24), back to work (SMD -3.14, 95 % CI -8.92, 2.64, p = 0.29), recurrence rate (OR 1.41, 95 % CI 0.81, 2.46, p = 0.23), and postoperative neuralgia (OR 0.48, 95 % CI 0.16, 1.46, p = 0.20).On the basis of our meta-analysis, we conclude that laparoscopic and open repair of incisional hernia is comparable. A larger randomized controlled multicenter trial with strict inclusion and exclusion criteria and standardized techniques for both repairs is required to demonstrate the superiority of one technique over the other.

This is an editorial note/letter on Simulation Comparison of the Quality Effects and Random Effects Methods of Metaanalysis.

Inference about population parameters could be improved using non- sample prior information (NSPI) from reliable sources along with the available data. This paper studies the problem of testing the intercept parameter of a simple regression model when NSPI is available on the value of the slope. The information on the slope may have the three different scenarios: (i) unknown (unspecified), (ii) known (certain or specified), and (iii) uncertain if the suspected value is unsure, for which we define the unrestricted test (UT), restricted test (RT) and pre-test test (PTT) for the intercept parameter. The test statistics, their sampling distributions, and power functions are derived. Comparison of the power functions and size of the tests are used to search and recommend a best test. The study reveals that the PTT has a reasonable dominance over the UT and RT both in terms of achieving highest power and lowest size.

This paper proposes the bivariate noncentral chi-square (BNC) distribution by compounding the Poisson probabilities with the bivariate central chi-square distribution. The probability density and cumulative distribution functions of the joint distribution of the two noncentral chi-square variables are derived for arbitrary values of the correlation coefficient, degrees of freedom(s), and noncentrality parameters. Computational procedures to calculate the upper tail probabilities as well as the percentile points for selected values of the parameters, for both equal and unequal degrees of freedom, are discussed. The graphical representation of the distribution for different values of the parameters are provided. Some applications of the distribution are outlined.

The M-estimation method is used to define the unrestricted test, restricted test and pre-test test (PTT) for testing the intercept vector of a multivariate simple regression model when it is a priori suspected that the slope vector has some specified values. The asymptotic distribution of the test statistics and the asymptotic power functions of the proposed M-tests are derived. Performances of the M-tests are compared both analytically and graphically. The analytical results as well as an illustrative simulation study to compare the size and power of the M-tests reveal a reasonable dominance of the PTT over the other two tests.

The aim of this study was to conduct a meta-analysis of randomized evidence to determine the relative merits of laparoscopic anti-reflux surgery (LARS) and open anti-reflux surgery (OARS) for proven gastro-esophageal reflux disease (GERD).A search of the Medline, Embase, Science Citation Index, Current Contents, and PubMed databases identified all randomized clinical trials that compared LARS and OARS and that were published in the English language between 1990 and 2007. A meta-analysis was carried out in accordance with the QUOROM (Quality of Reporting of Meta-Analyses) statement. The six outcome variables analyzed were operating time, hospital stay, return to normal activity, perioperative complications, treatment failure, and requirement for further surgery. Random-effects meta-analyses were carried out using odds ratios (ORs) and weighted mean differences (WMDs).Twelve trials were considered suitable for the meta-analysis. A total of 503 patients underwent OARS and 533 had LARS. For three of the six outcomes, the summary point estimates favored LARS over OARS. There was a significant reduction of 2.68 days in the duration of hospital stay for the LARS group compared with that for the OARS group (WMD: -2.68, 95% confidence interval (CI): -3.54 to -1.81; P0.0001), a significant reduction of 7.75 days in return to normal activity for the LARS group compared with that for the OARS group (WMD: -7.75, 95% CI: -14.37 to -1.14; P=0.0216), and finally, there was a statistically significant reduction of 65% in the relative odds of complication rates for the LARS group compared with that for the OARS group (OR: 0.35, 95% CI: 0.16-0.75; P=0.0072). The duration of operating time was significantly longer (39.02 min) in the LARS group (WMD: 39.02, 95% CI: 17.99-60.05; P=0.0003). Treatment failure rates were comparable between the two groups (OR: 1.39, 95% CI: 0.71-2.72; P=0.3423). Despite this, the requirement for further surgery was significantly higher in the LARS group (OR: 1.79, 95% CI: 1.00-3.22; P=0.05).On the basis of this meta-analysis, the authors conclude that LARS is an effective and safe alternative to OARS for the treatment of proven GERD. LARS enables a faster convalescence and return to productive activity, with a reduced risk of complications and a similar treatment outcome, than an open approach. However, there is a significantly higher rate of re-operation (79%) in the LARS group.

This article studies the performance of the unrestricted estimator (UE) and preliminary test estimator (PTE) of the slope parameter of simple linear regression model under linex loss function. The risk functions of both the UE and PTE are derived. The moment generating function (MGF) of the PTE is derived which turns out to be a component of the risk function. From the MGF the first two moments of the PTE are obtained and found to be identical to that obtained by using a different approach in Khan et al. (2002). The performance of the PTE is compared with that of the UE by using the analytical and graphical as well as the numerical methods. It is revealed that if the uncertain non sample prior information about the value of the slope is not too far from its true value then the PTE outperforms the UE.

Estimators of the intercept parameter of a simple linear regression model involves the slope estimator. In this article, we consider the estimation of the intercept parameters of two linear regression models with normal errors, when it is a priori suspected that the two regression lines are parallel, but in doubt. We also introduce a coefficient of distrust as a measure of degree of lack of trust on the uncertain prior information regarding the equality of two slopes. Three different estimators of the intercept parameters are defined by using the sample data, the non sample uncertain prior information, an appropriate test statistic, and the coefficient of distrust. The relative performances of the unrestricted, shrinkage restricted and shrinkage preliminary test estimators are investigated based on the analyses of the bias and risk functions under quadratic loss. If the prior information is precise and the coefficient of distrust is small, the shrinkage preliminary test estimator overperforms the other es...

This paper considers multiple regression model with multivariate spherically symmetric errors to determine optimal β-expectation tolerance regions for the future regression vector (FRV) and future residual sum of squares (FRSS) by using the prediction distributions of some appropriate functions of future responses. The prediction distribution of the FRV, conditional on the observed responses, is multivariate Student-t distribution. Similarly, the prediction distribution of the FRSS is a beta distribution. The optimal β-expectation tolerance regions for the FRV and FRSS have been obtained based on the F -distribution and beta distribution, respectively. The results in this paper are applicable for multiple regression model with normal and Student-t errors.

The estimation of the slope parameter of two linear regression models with normal errors are considered, when it is suspected that the two lines are parallel. The uncertain prior information about the equality of slopes is presented by a null hypothesis and a coefficient of distrust on the null hypothesis is introduced. The unrestricted estimator (UE) based on the sample responses and shrinkage restricted estimator (SRE) as well as shrinkage preliminary test estimator (SPTE) based on the sample responses and prior information are defined. The relative performances of the UE, SRE and SPTE are investigated based on the analysis of the bias, quadratic bias and quadratic risk functions. An example based on a health study data is used to illustrate the method. The SPTE dominates other two estimators if the coefficient of distrust is not far from 0 and the difference between the population slopes is small.

This paper considers alternative estimators of the intercept parameter of the linear regression model with normal error when uncertain non-sample prior information about the value of the slope parameter is available. The maximum likelihood, restricted, preliminary test and shrinkage estimators are considered. Based on their quadratic biases and mean square errors the relative performances of the estimators are investigated. Both analytical and graphical comparisons are explored. None of the estimators is found to be uniformly dominating the others. However, if the non-sample prior information regarding the value of the slope is not too far from its true value, the shrinkage estimator of the intercept parameter dominates the rest of the estimators.

This article examines the performance of the updated quality effects (QE) estimator for meta-analysis of heterogeneous studies. It is shown that this approach leads to a decreased mean squared error (MSE) of the estimator while maintaining the nominal level of coverage probability of the confidence interval. Extensive simulation studies confirm that this approach leads to the maintenance of the correct coverage probability of the confidence interval, regardless of the level of heterogeneity, as well as a lower observed variance compared to the random effects (RE) model. The QE model is robust to subjectivity in quality assessment down to completely random entry, in which case its MSE equals that of the RE estimator. When the proposed QE method is applied to a meta-analysis of magnesium for myocardial infarction data, the pooled mortality odds ratio (OR) becomes 0.81 (95% CI 0.61-1.08) which favors the larger studies but also reflects the increased uncertainty around the pooled estimate. In comparison, under the RE model, the pooled mortality OR is 0.71 (95% CI 0.57-0.89) which is less conservative than that of the QE results. The new estimation method has been implemented into the free meta-analysis software MetaXL which allows comparison of alternative estimators and can be downloaded from www.epigear.com.

The estimation of the mean of an univariate normal population with unknown variance is considered when uncertain non-sample prior information is available. Alternative estimators are denned to incorporate both the sample as well as the non-sample information in the estimation process. Some of the important statistical properties of the restricted, preliminary test, and shrinkage estimators are investigated. The performances of the estimators are compared based on the criteria of unbiasedness and mean square error in order to search for a ‘best’ estimator. Both analytical and graphical methods are explored. There is no superior estimator that uniformly dominates the others. However, if the non-sample information regarding the value of the mean is close to its true value, the shrinkage estimator over performs the rest of the estimators.

Improved James-Stein type estimation of the mean vector μ of a multovaroate Student-t population of dimension p with ν degrees of freedom is considered. In addition to the sample data, uncertain prior information on the value of the mean vector, in the form of a null hypothesis, is used for the estiamtion. The usual maximum liklihood estimator((mle) of μ is obtained and a test statistic for testing H0:μ=μ0 is derived. Based on the mle of μ and the tes statistic the preliminary test estimator (PTE), Stein-type shrinkage estimator (SE) and positive-rule shrinkage esiimator (PRSE) are defined. The bias and the quadratic risk of the estimators are evaiuated. The relative performances of the estimators are mvestigated by analyzing the risks under different condltlons It is observed that the FRSE dommates over he other three estimators, regardless of the vaiidity of the null hypothesis and the value ν.

INTRODUCTION: Bariatric surgery, including laparoscopic sleeve gastrectomy (LSG) and laparoscopic roux-en-y gastric bypass (LRYGB), are increasingly being performed to manage the burden of chronic and metabolic disease in obese individuals. We conduct a meta-analysis of randomized controlled trials (RCTs) to compare the surgical complications of LSG and LRYGB procedures and their impact on readmission rate, reoperation rate and 30 day mortality rate.

In the presence of an uncertain prior information about the value of the slope parameter, the estimation of the intercept parameter of a simple regression model with a multivariate Student-t error distribution is investigated. The unrestricted, restricted and shrinkage preliminary test maximum likelihood estimators are defined. The expressions for the bias and the mean square error of the three estimators are provided and the relative efficiences are analyzed. A maximin criterion is established, and graphs are constructed for an arbitrary number of degrees of freedom (D.F.) as well as sample sizes. A criterion to select optimal significance level is also discussed.

RESULTS: There were 102 patients included. Fifty-four patients (53%) had a hiatal hernia present, and 15 underwent concurrent repair. Eleven patients (11%) underwent a concurrent abdominal procedure. Mean follow-up duration was 7.6 months. GERD medication use decreased from 98% preoperative to 8% postoperative (p

Aims and objective: The aim was to conduct a meta-analysis and systematic review of RCTs comparing two methods of colonic insufflation for elective colonoscopy i.e. carbon dioxide or air and to evaluate their efficiency, safety and side effects. Material and Methods: Prospective RCTs comparing carbon dioxide versus air insufflation for colonic distension during colonoscopy were selected by searching PubMed, Medline, Embase, Science Citation Index, Current Contents, and the Cochrane Central Register of Controlled Trials published between January 1980 and October 2014.The outcome variables analyzed included procedural and immediate post-procedural pain (during, end or within 15 min after procedure), early post-procedural pain (between 30-120 min), intermediate post-procedural pain (360 min) and late post-procedural pain (720-1140 min), cecal/ileal intubation rate, cecal/ileal intubation time, and total colonoscopy examination time. These outcomes were unanimously decided to be important since they influence the practical approach towards patient management within and outside of hospital. Random effects model was used to calculate the effect size of both binary and continuous data. Heterogeneity amongst the outcome variables of these trials was determined by the Cochran Q statistic and I2 index. The meta-analysis was prepared in accordance with PRISMA guidelines. Results: Twenty four RCTs totaling 3996 patients (CO2=2017, Air=1979) were analyzed. Statistically significant differences for the pooled effect size were observed for procedural and immediate post-procedural pain (WMD 0.49, 95% CI 0.32, 0.73, p= 0.0005), early post-procedural pain between 30 and 120 minutes (WMD 0.25, 95% CI 0.12, 0.49, p=

Purpose: The therapeutic benefit of D2 gastrectomy for gastric carcinoma has not been clearly demonstrated in RCTs. The aim was to conduct a meta-analysis of RCTs to investigate the merits of D1 versus D2 gastrectomy for the treatment of gastric cancer. Methodology: A search of Medline, Embase, Science Citation Index, Current Contents, PubMed and the Cochrane Database identified all RCTs comparing D1 versus D2 gastrectomy published in the English Language between 1980 and 2007. The six variables analysed included anastomotic leak, re-operation rate, overall complications, mortality, hospital stay and 5 year survival. Results: Six trials totalling 1591 patients (D1 = 813, D2 = 778) were analysed. There was a significant reduction of 60% in the relative odds of anastomotic leaks for D1, a significant reduction of 61% in relative odds of postoperative complications for D1, a significant lesser risk of 66% in the odds ratio of re-operation for D1 and a significant decrease of 7.15 days of duration of hospital stay for D1. The relative odds of mortality favoured D1 group (17% reduction of death) as well. Lastly the 5 year survival between the two groups was not different. Conclusion: Based on this meta-analysis, D1 gastrectomy is associated with significant fewer anastomotic leaks, postoperative complications; re-operation rate and decreased length of hospital stay. Furthermore the trend in mortality favoured D1 gastrectomy compared to D2 cohort. Lastly the five year survival in D1 gastrectomy patients was not compromised compared to D2 cohort.

Purpose: Providing enteral supplements containing ‘immunonutrition’ has been proposed to decrease postoperative complications and duration of hospital stay for elective surgical patients. This meta-analysis was undertaken to elucidate the potential benefit of providing immune-enhanced nutrition in surgical patients. Methodology: A search of Medline, Embase, Science Citation Index, PubMed and the Cochrane Database identified all RCTs comparing the use of perioperative immunonutrition with standard nutrition provision in elective adult surgical patients between 1990 and 2008. The variables analysed included mortality, total complications, infective complications, anastomotic leak and length of hospital stay. Results: 21 distinct studies were identified that met inclusion criteria involving 2135 patients (immunonutrition n = 1100; standard nutrition n = 935). The provision of immunonutrition was shown to be associated with significant reductions in the incidence of total postoperative complications (OR 0.50, 95% CI 0.37, 0.69, p < 0.0001), postoperative infective complications (OR 0.47, 95% CI 0.37, 0.60, p < 0.0001), anastomotic breakdown (OR 0.43, 95% 0.25, 0.75, p = 0.003), and the duration of hospital stay (WMD −2.95, 95% CI −4.01, −1.88, p < 0.0001) when compared to standard nutritional provision. No differences were seen between interventions with relation to mortality (OR 0.90, 95% CI 0.41, 1.97. p = 0.8). Conclusion: Provision of immunonutrition in preference to standard nutrition was associated with clinically significant decreased length of hospital stay, reduction in the development of postoperative complications including those of infective origin and anastomotic breakdown but has no impact on mortality.