Z SCORE DEFINITION SOFTWARE
Z SCORE DEFINITION WINDOWS

Z SCORE DEFINITION WINDOWS

for R for Windows (version 3.1.2) (The R Foundation for Statistical Computing, Vienna, Austria). Reclassification Indices were calculated using improve improveProb function from Hmisc (Harrel Miscellaneous) package (version 3.14-6) authored by Frank E. Increase in sensitivity and specificity was calculated from Reclassification tables. Improvement in C statistic and Reclassification Indices were used to compare the improvement in the predictability of ACC score for mortality with the addition of Z score. Discrimination and calibration of the ACC model were assessed using C statistic and Hosmer–Lemeshow test, respectively. Prevalence of underweight (Z −0.9 and OR were calculated from a binary logistic regression model. The cohort was divided into 10 categories on the basis of Z score and mortality in each category was analyzed. Continuous data are summarized as mean and standard deviation or median with interquartile range (IQR). The primary outcome was in-hospital mortality defined as all-cause mortality in same hospital admission as CHD surgery.ĭescriptive data are summarized in Table 1. This represents the optimum growth of babies and is derived from WHO Multicentre Growth Reference Study, which included 8500 children, from 6 countries belonging to different regions including India. It is developed for monitoring growth in individuals of 0-60 months based on WHO Child Growth Standards (WHO CGS).

Z SCORE DEFINITION SOFTWARE

Z score was calculated for individual patient using WHO Anthro software version 3.2.2, January 2011, (World Health Organization, Geneva, Switzerland) available from.

Patients with incomplete data were excluded. Data regarding age, gender, weight, diagnosis, procedure, CPB time were collected from hospital records, and ACC scores were calculated. All patients of younger than 5 years who underwent cardiac surgery for CHD, from July 2007 to June 2013, under single surgical unit at our institute were enrolled. Institutional Ethical Committee approval was obtained. This was a single center, retrospective, observational study. This study was conducted to study the distribution of weight-for-age Z score (hereafter mentioned as Z score), its association to mortality and improvement of ACC model with addition of Z score to predict mortality, in Indian cardiac surgical population below 5 years. In Indian population ACC score has been found to have less than acceptable discrimination. Thus, ACC score takes into account the absolute weight of 2.5 kg as a cutoff and fails to consider weight-for-age. Body weight of <2.5 kg is taken as a procedure independent complexity factor and scored accordingly. It takes into account procedure-related and procedure-independent factors. WHO recommends using -2 Z (2.3 rd percentile) scores for diagnosis of underweight and -3 Z (0.1 percentile) for the diagnosis of severe underweight.Īristotle comprehensive complexity (ACC) score predicts outcome after pediatric cardiac surgeries and has been validated in multiple populations. Z scores (in contrast to percentiles) can quantify extreme values, are gender-independent, and allows comparison across age-groups and populations. Thus, a Z score of −2, indicates weight-for-age which is 2 standard deviations below the reference mean and corresponds to 2.3 rd percentile. The Z score system expresses weight-for-age as the number of standard deviations or Z score below or above the reference mean or median value. WHO recommends the use of Z (standard) score to describe weight-for-age. Though the effect of low body weight has been analyzed in CHD population, the effect of low weight-for-age has not been studied. Nutritional deficiency, recurrent infections, etc., contribute to malnutrition. Low weight-for-age, a manifestation of malnutrition, is important in developing countries where patients present late. Low body weight can either be low absolute weight which is adequate for age or low weight-for-age. Low body weight, which is prevalent in congenital heart disease (CHD) patients, has been associated with worse outcomes after pediatric cardiac surgery.

Z score definition