Cancer incidence in kidney transplant recipients: a study protocol

<p>Abstract</p> <p>Background</p> <p>Different publications show an increased incidence of neoplasms in renal transplant patients. The objective of this study is to determine the incidence of cancer in the recipients of renal transplants performed in the A Coruña Hospital (Spain) during the period 1981–2007.</p> <p>Methods/Design</p> <p>During the study period 1967 kidney transplants were performed, corresponding to 1710 patients. Patients with neoplasms prior to the transplant will be excluded (n = 38). A follow-up study was carried out in order to estimate cancer incidence after transplantation.</p> <p>For each patient, information included donor and recipient characteristics, patients and graft survival and cancer incidence after transplantation. Incident cancer is considered as new cases of cancer after the transplant with anatomopathological confirmation. Their location will be classified according to the ICD-9.</p> <p>The analysis will be calculated using the indirect standardisation method. Age-adjusted cancer incidence rates in the Spanish general population will be obtained from the Carlos III Health Institute, the National Epidemiology Centre of the Ministry of Science and Technology. Crude first, second and third-year post-transplantation cancer incidence rates will be calculated for male and female recipients. The number of cases of cancer at each site will be calculated from data in the clinical records. The expected number of cancers will be calculated from data supplied by the Carlos III Health Institute. For each tumour location we will estimate the standardized incidence ratios (SIRs), using sex-specific cancer incidence rates, by dividing the incidence rate for the transplant patients by the rate of the general population. The 95% confidence intervals of the SIRs and their associated p-values will be calculated by assuming that the observed cancers follow a Poisson distribution. Stratified analysis will be performed to examine the variation in the SIRs with sex and length of follow-up.</p> <p>Competing risk survival analysis methods will be applied to estimate the cumulative incidence of cancer and to identify variables associated to its occurrence.</p> <p>Discussion</p> <p>Information about cancer incidence in kidney transplant patients could be useful to adapt the guidelines on post-kidney transplant follow-up on tumour screening, and evaluate the impact of intervention measures for the prevention of cancer in these patients.</p

Acute gastroenteritis hospitalizations among children aged < 5 years before and after introduction of rotavirus vaccines: A hospital-based surveillance study in Galicia, Spain

Rotavirus vaccines were licensed in Spain between late 2006 and early 2007. Rotavirus vaccination was recommended but not reimbursed by the Spanish National Health System. Significant coverage rates have been reached in Galicia, with an average of 47% since the period July 2007-June 2008. We aim to explore eventual variations in the incidence of hospitalizations for acute gastroenteritis (AGE) among children < 5 y of age before and after vaccine introduction. The annual and monthly hospitalization rates for rotavirus-related AGE and all cause AGE, before and after rotavirus vaccine introduction, were calculated by using the official surveillance system for hospital data. The annual hospitalization rates for rotavirus-related AGE in children < 5 y of age decreased by 14.8% for the period July 2008 to June 2009 and by 44.5% for the period July 2009 to June 2010 as compared with the median rate of the pre-vaccination period (July 2003 to June 2007). The corresponding decreases for all cause AGE were 29.9% and 49.0%, respectively. In children < 12 mo of age a more marked decrease was observed. Compared with pre-vaccination years, a decrease in rotavirus-related and all cause AGE hospitalization rates was observed, with a greater decline in the July 2009 to June 2010 perio

Time series clustering on lower tail dependence for portfolio selection

In this paper we analyse a case study based on the procedure introduced by De Luca and Zuccolotto (2011), whose aim is to cluster time series of financial returns in groups being homogeneous in the sense that their joint bivariate distributions exhibit high association in the lower tail. The dissimilarity measure used for such clustering is based on tail dependence coefficients estimated using copula functions. We carry out the clustering using an algorithm requiring a preliminary transformation of the dissimilarity index into a distance metric by means of a geometric representation of the time series, obtained with Multidimensional Scaling. We show that the results of the clustering can be used for a portfolio selection purpose, when the goal is to protect investments from the effects of a financial crisis