Browsing by Author "Ren, Xiaowei"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Acute Alcoholic Hepatitis: Natural History and Predictors of Mortality Using a Multicenter Prospective Study
    (Elsevier, 2017-04-28) Lourens, Spencer; Sunjaya, Dharma B.; Singal, Ashwani; Liangpunsakul, Suthat; Puri, Puneet; Sanyal, Arun; Ren, Xiaowei; Gores, Gregory J.; Radaeva, Svetlana; Chalasani, Naga; Crabb, David W.; Katz, Barry; Kamath, Patrick S.; Shah, Vijay H.; Biostatistics, School of Public Health
    Objective: To examine the natural history of acute alcoholic hepatitis (AH) and identify predictors of mortality for AH using data from a prospective multicenter observational study. Participants and Methods: We analyzed data from 164 patients with AH and 131 heavy-drinking controls with no liver disease. Participants underwent clinical/laboratory assessment at baseline and 6 and 12 months after enrollment. Multivariable analyses were conducted to identify variables associated with mortality and examine the association between coffee drinking and risk of AH. Results: Thirty-six patients with AH died during follow-up, with estimated 30-day, 90-day, 180-day, and 1-year survival of 0.91 (95% CI, 0.87-0.96), 0.85 (95% CI, 0.80-0.91), 0.80 (95% CI, 0.74-0.87), and 0.75 (95% CI, 0.68-0.83), respectively. In the multivariable analysis, higher serum bilirubin level (hazard ratio [HR]=1.059; 95% CI, 1.022-1.089), lower hemoglobin level (HR=1.263; 95% CI, 1.012-1.575), and lower platelet count (HR=1.006; 95% CI, 1.001-1.012) were independently associated with mortality in AH. Compared with controls, fewer patients with AH regularly consumed coffee (20% vs 44%; P<.001), and this association between regular coffee drinking and lower risk of AH persisted after controlling for relevant covariates (odds ratio=0.26; 95% CI, 0.15-0.46). Time-dependent receiver operating characteristic curve analysis revealed that Model for End-Stage Liver Disease; Maddrey Discriminant Function; age, serum bilirubin, international normalized ratio, and serum creatinine; and Child-Pugh scores all provided similar discrimination performance at 30 days (area under the curve=0.73-0.77). Conclusion: Alcoholic hepatitis remains highly fatal, with 1-year mortality of 25%. Regular coffee consumption was associated with lower risk of AH in heavy drinkers.
  • Thumbnail Image
    Item
    Computed tomography assessment of peripubertal craniofacial morphology in a sheep model of binge alcohol drinking in the first trimester
    (Elsevier, 2015-11) Birch, Sharla M.; Lenox, Mark W.; Kornegay, Joe N.; Shen, Li; Ai, Huisi; Ren, Xiaowei; Goodlett, Charles R.; Cudd, Tim A.; Washburn, Shannon E.; Department of Medical & Molecular Genetics, IU School of Medicine
    Identification of facial dysmorphology is essential for the diagnosis of fetal alcohol syndrome (FAS); however, most children with fetal alcohol spectrum disorders (FASD) do not meet the dysmorphology criterion. Additional objective indicators are needed to help identify the broader spectrum of children affected by prenatal alcohol exposure. Computed tomography (CT) was used in a sheep model of prenatal binge alcohol exposure to test the hypothesis that quantitative measures of craniofacial bone volumes and linear distances could identify alcohol-exposed lambs. Pregnant sheep were randomly assigned to four groups: heavy binge alcohol, 2.5 g/kg/day (HBA); binge alcohol, 1.75 g/kg/day (BA); saline control (SC); and normal control (NC). Intravenous alcohol (BA; HBA) or saline (SC) infusions were given three consecutive days per week from gestation day 4-41, and a CT scan was performed on postnatal day 182. The volumes of eight skull bones, cranial circumference, and 19 linear measures of the face and skull were compared among treatment groups. Lambs from both alcohol groups showed significant reduction in seven of the eight skull bones and total skull bone volume, as well as cranial circumference. Alcohol exposure also decreased four of the 19 craniofacial measures. Discriminant analysis showed that alcohol-exposed and control lambs could be classified with high accuracy based on total skull bone volume, frontal, parietal, or mandibular bone volumes, cranial circumference, or interorbital distance. Total skull volume was significantly more sensitive than cranial circumference in identifying the alcohol-exposed lambs when alcohol-exposed lambs were classified using the typical FAS diagnostic cutoff of ≤10th percentile. This first demonstration of the usefulness of CT-derived craniofacial measures in a sheep model of FASD following binge-like alcohol exposure during the first trimester suggests that volumetric measurement of cranial bones may be a novel biomarker for binge alcohol exposure during the first trimester to help identify non-dysmorphic children with FASD.
  • Thumbnail Image
    Item
    Effects of Age, Sex, Body Weight, and Quantity of Alcohol Consumption on Occurrence and Severity of Alcoholic Hepatitis
    (Elsevier, 2016-12) Liangpunsakul, Suthat; Puri, Puneet; Shah, Vijay; Kamath, Patrick; Sanyal, Arun; Urban, Thomas; Ren, Xiaowei; Katz, Barry; Radaeva, Svetlana; Chalasani, Naga; Crabb, David W.; Medicine, School of Medicine
    Background & Aims Only a minority of heavy drinking individuals develop alcoholic hepatitis (AH), for unclear reasons. We analyzed data from the Translational Research and Evolving Alcoholic Hepatitis Treatment cohort: subjects who drink heavily with normal results from liver tests (controls) and patients with AH. We examined risk factors for the development of AH including body mass index (BMI), drinking pattern and quantity, and sex. Methods We compared data from 145 patients with AH cases and 124 controls, based on BMI when they joined the cohort; groups were matched for sex and race. Drinking patterns were assessed using the time line follow back method, the Alcohol Use Disorders Identification Test, and National Institute of Alcohol Abuse and Alcoholism 6-question survey. We performed univariable and multivariable analyses we to assess effects of these factors and their interaction in increasing the risk for AH. We also explored the association between PNPLA3 variants and AH. Results Cases with AH were older (47 vs 44 years; P=.03). For nearly all measures of quantity of alcohol consumed or frequency of binge drinking, controls drank more heavily than cases with AH. We did not find an association between BMI, sex, drinking patterns, and the presence of AH. Age and BMI were independent predictors for severity of AH. When we analyzed cases and controls of European ancestry, the PNPLA3 single nucleotide polymorphism rs738409 was associated with risk for AH (odds ratio, 1.89; P=.007). Conclusion Compared with heavy drinkers without liver disease, subjects with AH consumed lower levels of alcohol and had less binge drinking, suggesting an increased sensitivity to the toxic effects of alcohol. The risk for AH may be associated with the PNPLA3 rs738409 polymorphism.
  • Thumbnail Image
    Item
    Longitudinal Development of Refractive Error in Children With Accommodative Esotropia: Onset, Amblyopia, and Anisometropia.
    (iOVS, 2016-04) Wang, Jingyun; Morale, Sarah E.; Ren, Xiaowei; Birch, Eileen E.; Department of Biostatistics, Richard M. Fairbanks School of Public Health
    Purpose: We investigated longitudinal changes of refractive error in children with accommodative esotropia (ET) throughout the first 12 years of life, its dependence on age at onset of ET, and whether amblyopia or anisometropia are associated with defective emmetropization. Methods: Longitudinal refractive errors in children with accommodative ET were analyzed retrospectively. Eligibility criteria included: initial hyperopia ≥+4.00 diopters (D), initial cycloplegic refraction before 4 years, at least 3 visits, and at least one visit between 7 and 12 years. Children were classified as having infantile (N = 30; onset ≤12 months) or late-onset (N = 78; onset at 18–48 months) accommodative ET. Cycloplegic refractions culled from medical records were converted into spherical equivalent (SEQ). Results: Although the initial visit right eye SEQ was similar for the infantile and late-onset groups (+5.86 ± 1.28 and +5.67 ± 1.26 D, respectively), there were different developmental changes in refractive error. Neither group had a significant decrease in hyperopia before age 7 years, but after 7 years, the infantile group experienced a myopic shift of −0.43 D/y. The late-onset group did not experience a myopic shift at 7 to 12 years. Among amblyopic children, a slower myopic shift was observed for the amblyopic eye. Among anisometropic children, the more hyperopic eye experienced more myopic shift than the less hyperopic eye. Conclusions: Children with infantile accommodative ET experienced prolonged hyperopia followed by a myopic shift after 7 years of age, consistent with dissociation between infantile emmetropization and school age myopic shift. In contrast, children with late-onset accommodative ET had little myopic shift before or after 7 years.
  • Thumbnail Image
    Item
    The utility of commonly used laboratory tests to screen for excessive alcohol use in clinical practice
    (Wiley, 2015-08) Gough, Gina; Heathers, Laura; Puckett, Deonna; Westerhold, Chi; Ren, Xiaowei; Yu, Zhangsheng; Crabb, David W.; Liangpunsakul, Suthat; Department of Medicine, IU School of Medicine
    BACKGROUND: This current study was undertaken to carefully assess the accuracy of routinely used laboratory tests in detecting excessive/recent alcohol use. We also determined the kinetics of these markers in subjects who underwent an intensive alcohol rehabilitation program. METHODS: The study cohort consisted of 210 nonexcessive drinkers, 272 excessive drinkers, and 76 with alcoholic cirrhosis. To determine the kinetics of these markers during alcohol abstinence, we followed 45 subjects with history of excessive alcohol use for 12 weeks during the intensive alcohol treatment program. RESULTS: Percentage of carbohydrate deficient transferrin (%CDT) provided the highest diagnostic performance (area under the curve [AUC] 0.77) followed by gamma-glutamyl transferase (GGT) (AUC 0.68) to detect excessive drinkers. The percentage of excessive drinkers with aspartate aminotransferase:alanine aminotransferase (AST:ALT) > 2 was only 2%, whereas 51% of subjects with alcoholic cirrhosis had AST:ALT > 2. In the multivariate analysis, the levels of GGT and %CDT were associated with the level of alcohol consumed during the past 30 days. The levels of GGT, mean corpuscular volume (MCV), and %CDT were significantly lower compared to those at baseline before alcohol rehabilitation, whereas the AST, ALT, and AST:ALT ratio were unchanged. The percent reduction was ~2.7% (for MCV), 19% (for GGT), and 43% (for %CDT) at the end of the 12-week follow-up compared to the baseline. CONCLUSIONS: %CDT are useful markers to screen for excessive alcohol use and for follow-up of abstinence. Most subjects with excessive alcohol use do not have a high AST:ALT ratio. Rather, the AST:ALT > 2 is suggestive of alcoholic cirrhosis. The performance of the %CDT to screen for heavy alcohol use is still not ideal. Further research to identify the noninvasive marker(s) (i.e., using proteomic or metabolomics approach) should be considered.
  • Thumbnail Image
    Item
    Variable selection and prediction for complex survival data analysis
    (2017-05-17) Ren, Xiaowei; Yu, Zhangsheng; Li, Shanshan
    Survival analysis methods for time-to-event data are commonly used in biomedical researches. It is essential to select the important variables and identify the correct covariate functional form. After selection of important variables, it is of interest to evaluate the prediction performance of the selected model, typically by receiver oper ating characteristic (ROC) curve. Furthermore, the analysis of time-to-event data is complicated by the presence of interval censoring and dependent competing events, both of which occur frequently in clinical studies. In this dissertation, we set to de velop variable selection and prediction methods for complex survival data. In the first topic, we proposed a two-stage procedure to identify the linear and/or non-linear co variates functional forms simultaneously and estimate the selected covariate effects for competing risks data. Spectral decomposition was used to decompose the nonpara metric covariate function. The adaptive LASSO method was then to select the linear and non-linear components, respectively. We showed that our method achieved good selection accuracy and minimal estimation biases. In the second topic, to evaluate the prediction performance, we extended the ROC function estimation of right-censored competing risks data to interval-censored data. We proved the consistency of the estimator and demonstrated the convergence of estimator in numerical studies. In the third topic, we extended the ROC function for independent survival data to clustered survival data using within-cluster-resampling (WCR) technique. All the three methods had been implemented in real data as illustration.