Body mass index and outcome in renal transplant recipients: a systematic review and meta-analysis

BACKGROUND: Whether overweight or obese end stage renal disease (ESRD) patients are suitable for renal transplantation (RT) is often debated. The objective of this review and meta-analysis was to systematically investigate the outcome of low versus high BMI recipients after RT. METHODS: Comprehensive searches were conducted in MEDLINE OvidSP, Web of Science, Google Scholar, Embase, and CENTRAL (the Cochrane Library 2014, issue 8). We reviewed four major guidelines that are available regarding (potential) RT recipients. The methodology was in accordance with the Cochrane Handbook for Systematic Reviews of Interventions and written based on the PRISMA statement. The quality assessment of studies was performed by using the GRADE tool. A meta-analysis was performed using Review Manager 5.3. Random-effects models were used. RESULTS: After identifying 5,526 studies addressing this topic, 56 studies were included. We extracted data for 37 outcome measures (including data of more than 209,000 RT recipients), of which 26 could be meta-analysed. The following outcome measures demonstrated significant differences in favour of low BMI (<30) recipients: mortality (RR = 1.52), delayed graft function (RR = 1.52), acute rejection (RR = 1.17), 1-, 2-, and 3-year graft survival (RR = 0.97, 0.95, and 0.97), 1-, 2-, and 3-year patient survival (RR = 0.99, 0.99, and 0.99), wound infection and dehiscence (RR = 3.13 and 4.85), NODAT (RR = 2.24), length of hospital stay (2.31 days), operation duration (0.77 hours), hypertension (RR = 1.35), and incisional hernia (RR = 2.72). However, patient survival expressed in hazard ratios was in significant favour of high BMI recipients. Differences in other outcome parameters were not significant. CONCLUSIONS: Several of the pooled outcome measurements show significant benefits for ‘low’ BMI (<30) recipients. Therefore, we postulate that ESRD patients with a BMI >30 preferably should lose weight prior to RT. If this cannot be achieved with common measures, in morbidly obese RT candidates, bariatric surgery could be considered. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12916-015-0340-5) contains supplementary material, which is available to authorized users

Age-incidence artifacts do not account for the season-of-birth effect in schizophrenia

Contrary to the position taken by Lewis (1989), several articles have demonstrated an association between season of birth and the risk of schizophrenia after controlling for the age-incidence effect. The method used by Pulver et al. (1983) was misinterpreted by Lewis. Clarification of this method is provided along with additional references related to the season-of-birth issue

Identification of sequence variants and analysis of the role of the catechol-O-methyl-transferase gene in schizophrenia susceptibility

BACKGROUND: Deletions of 1.5-2 MB of chromosome 22q11 have been previously associated with schizophrenia. The deleted region includes proximally the region harboring genes involved in DiGeorge and velocardiofacial syndromes. Distally, it includes the gene for catechol-O-methyl-transferase (COMT), an enzyme that catalyzes the O-methylation of catecholamine neurotransmitters, including dopamine, and which therefore is considered a candidate gene for schizophrenia. METHODS: We address the issue of a direct involvement of the COMT gene in the development of schizophrenia by employing the first extensive mutational analysis of this gene in a sample of 157 schizophrenia patients and 129 healthy controls, using single-strand conformation polymorphism and chemical cleavage methodologies. RESULTS: No mutations were found, but several sequence variants were identified, including the genetic polymorphism that underlies the high/low activity of the enzyme (a Val158-->Met change, which results in the creation of an NlaIII restriction site in the low-activity allele). The distribution of the NlaIII genotypes among subsets of schizophrenia patients was analyzed. CONCLUSIONS: The results presented here argue against a major role of COMT in schizophrenia in general (although a minor effect could not be excluded) and represent a first step toward a more refined delineation of the phenotype/genotype relationship between 22q11 microdeletions and schizophrenia susceptibility