Use Of Multivariate Regression Models Research Articles

Chronic Cough-Related Differences in Brain Morphometry in Adults: A Population-Based Study

Individuals with cough hypersensitivity have increased central neural responses to tussive stimuli, which may result in maladaptive morphometric changes in the central cough processing systems. Are the volumes of the brain regions implicated in cough hypersensitivity different in adults with chronic cough compared with adults without chronic cough? Between 2009 and 2014, participants in the Rotterdam Study, a population-based cohort, underwent brain MRI and were interviewed for chronic cough, which was defined as daily coughing for at least 3months. Regional brain volumes were quantified with the use of parcellation software. Based on literature review, we identified and studied seven brain regions that previously had been associated with altered functional brain activity in chronic cough. The relationship between chronic cough and regional brain volumes was investigated with the use of multivariable regression models. Chronic cough was prevalent in 9.6%(No.= 349) of the 3,620 study participants (mean age, 68.5 ± 9.0 years; 54.6%female). Participants with chronic cough had significantly smaller anterior cingulate cortex volume than participants without chronic cough (mean difference, -126.16mm3; 95%CI, -245.67 to -6.66; P= .039). Except for anterior cingulate cortex, there were no significant difference in the volume of other brain regions based on chronic cough status. The volume difference in the anterior cingulate cortex was more pronounced in the left hemisphere (mean difference, -88.11mm3; 95%CI, -165.16 to -11.06; P= .025) and in male participants (mean difference, -242.58mm3; 95%CI, -428.60 to -56.55; P= .011). Individuals with chronic cough have a smaller volume of the anterior cingulate cortex, which is a brain region involved in cough suppression. The Netherlands National Trial Registry (NTR; www.trialregister.nl) and the World Health Organization's International Clinical Trials Registry Platform (ICTRP; www.who.int/ictrp/network/primary/en/) under the joint catalogue number NTR6831.

Spain’s Loss of Human Capital after the Civil War: Spanish Refugees in Mexico

Abstract Among the important consequences of non-voluntary migration due to forced exile is the loss of human capital in the country of origin. Quantitative measurement of the human capital represented by the Spanish refugees who migrated to Mexico after the Spanish Civil War is largely missing from the economic-history literature. The use of multivariate regression models, focusing on occupation, height, and foreign-language facility as proxies of human capital, finds that the Spanish Republican refugees to Mexico presented a premium of human capital exceeding that of traditional economic migrants from Spain to Mexico, who were already considered “privileged.” The data sources also allow the analysis to isolate the human capital of the exiled women, thereby overcoming the traditional invisibility of women in recorded economic history.

Preoperative beta-blocker in ventricular dysfunction patients: need a more granular quality metric

BackgroundThe use of preoperative beta-blockers has been accepted as a quality standard for patients undergoing coronary artery bypass graft (CABG) surgery. However, conflicting results from recent studies have raised questions concerning the effectiveness of this quality metric. We sought to determine the influence of preoperative beta-blocker administration before CABG in patients with left ventricular dysfunction.MethodsThe authors analyzed all cases of isolated CABGs in patients with left ventricular ejection fraction less than 50%, performed between 2012 January and 2017 June, at 94 centres recorded in the China Heart Failure Surgery Registry database. In addition to the use of multivariate regression models, a 1–1 propensity scores matched analysis was performed.ResultsOf 6116 eligible patients, 61.7% received a preoperative beta-blocker. No difference in operative mortality was found between two cohorts (3.7% for the non-beta-blockers group vs. 3.0% for the beta-blocker group; adjusted odds ratio [OR] 0.82 [95% CI 0.58–1.15]). Few differences in the incidence of other postoperative clinical end points were observed as a function of preoperative beta-blockers except in stroke (0.7% for the non-beta-blocker group vs. 0.3 for the beta-blocker group; adjusted OR 0.39 [95% CI 0.16–0.96]). Results of propensity-matched analyses were broadly consistent.ConclusionsIn this study, the administration of beta-blockers before CABG was not associated with improved operative mortality and complications except the incidence of postoperative stroke in patients with left ventricular dysfunction. A more granular quality metric which would guide the use of beta-blockers should be developed.

Association between smoking and in-hospital mortality in patients with left ventricular dysfunction undergoing coronary artery bypass surgery: a propensity-matched study

BackgroundData on the effect of smoking on In-hospital outcome in patients with left ventricular dysfunction undergoing coronary artery bypass graft (CABG) surgery are limited. We sought to determine the influence of smoking on CABG patients with left ventricular dysfunction.MethodsA retrospective study was conducted using data from the China Heart Failure Surgery Registry database. Eligible patients with left ventricular ejection fraction less than 50% underwent isolated CABGS were included. In addition to the use of multivariate regression models, a 1–1 propensity scores matched analysis was performed. Our study (n = 6531) consisted of 3635 smokers and 2896 non-smokers. Smokers were further divided into ex-smokers (n = 2373) and current smokers (n = 1262).ResultsThe overall in-hospital morality was 3.9%. Interestingly, current smokers have lower in-hospital mortality than non-smokers [2.3% vs 4.9%; adjusted odds ratio (OR) 0.612 (95% CI 0.395–0.947) ]. No difference was detected in mortality between ex-smokers and non-smokers [3.6% vs 4.9%; adjusted OR 0.974 (0.715–1.327)]. No significant differences in other clinical end points were observed. Results of propensity-matched analyses were broadly consistent.ConclusionsIt is paradoxically that current smokers had lower in-hospital mortality than non-smokers. Future studies should be performed to further understand the biological mechanisms that may explain this ‘smoker’s paradox’ phenomenon.

Platelet function and activation in Cavalier King Charles Spaniels with subclinical chronic valvular heart disease.

OBJECTIVE To assess platelet closure time (CT), mean platelet component (MPC) concentration, and platelet component distribution width (PCDW) in dogs with subclinical chronic valvular heart disease. ANIMALS 89 Cavalier King Charles Spaniels (CKCSs) and 39 control dogs (not CKCSs). PROCEDURES Platelet count, MPC concentration, PCDW, and Hct were measured by use of a hematology analyzer, and CT was measured by use of a platelet function analyzer. Murmur grade and echocardiographic variables (mitral valve regurgitant jet size relative to left atrial area, left atrial-to-aortic diameter ratio, and left ventricular internal dimensions) were recorded. Associations between explanatory variables (sex, age, murmur grade, echocardiographic variables, platelet count, and Hct) and outcomes (CT, MPC concentration, and PCDW) were examined by use of multivariate regression models. RESULTS A model with 5 variables best explained variation in CT (R(2), 0.74), with > 60% of the variance of CT explained by mitral valve regurgitant jet size. The model of best fit to explain variation in MPC concentration included only platelet count (R(2), 0.24). The model of best fit to explain variation in PCDW included platelet count and sex (R(2), 0.25). CONCLUSIONS AND CLINICAL RELEVANCE In this study, a significant effect of mitral valve regurgitant jet size on CT was consistent with platelet dysfunction. However, platelet activation, as assessed on the basis of the MPC concentration and PCDW, was not a feature of subclinical chronic valvular heart disease in CKCSs.

Young cancer survivors’ expectations of physicians for issues of mental health, interpersonal relationships, and reintegration to society.

208 Background: As patients transition from cancer treatment to survivorship, issues surrounding the social and mental health impacts of survivorship gain increased importance. In this study, we examined young cancer survivors’ expectations of their physicians with respect to mental health, interpersonal relationships, and reintegration back to work and school. We also explored factors associated with these expectations. Methods: We surveyed patients aged 20 to 39 years who were diagnosed with solid tumors, evaluated at any 1 of 5 regional cancer centers in British Columbia, and alive at 2 or more years after their diagnosis. We explored the relationship between patient factors and expectations, adjusting for confounders through the use of multivariate regression models. Results: With a survey response rate of 57%, a total of 447 patients were analyzed: median age was 35 years (IQR 31-38), 30% were men, and 89% had ECOG 0. Tumor sites included breast (222; 50%), testicular (126; 28%), gynecological (76; 17%), and colorectal (23; 5%). Decreasing levels of expectations of cancer specialist (CS) were seen with 72%, 48%, and 28% of patients indicating that their CS should have some to full responsibility on issues related to mental health, social counselling, and reintegration, respectively. Compared to CS, patients held much higher expectations of their primary care physician (PCP) taking some to full responsibility for these same issues (see Table). Expectations of their PCP were further increased when there was frequent contact between patient and PCP. Conclusions: The majority of young cancer survivors in our survey expected their PCP more than their CS to have a significant degree of responsibility for mental, interpersonal, and social issues arising from their cancer or treatment. Early integration of PCP into survivorship care models may augment the work provided by the psychosocial cancer team and ease the transition to survivorship for patients. [Table: see text]

PP.19.11

Objective: To identify risk factors for its association with any diabetic nephropathy. Design and method: Retrospectively we studied 82 diabetic patients charts (20 with microalbuminuria, 23 with macroalbuminuria and 39 controls – with normoalbuminuria) in whom type 1 diabetes (T1DM) was diagnosed before the age of 15 years and duration of diabetes more than 20 years in Moscow district. All patients were matched by age (mean age of 35, 2 years), age at onset of diabetes (mean age 13,4 years) sex and duration of diabetes (mean 24,2 years). The relation between possible risk factors and development of micro- and macroalbuminuria was analysed with the use of multivariable regression models. Variables included in the model were: age, sex, age at onset of diabetes, duration of diabetes, glycosylated hemoglobin (HbA1c) level, lipids and blood pressure. Results: In comparison with normoalbuminuric subjects, both micro- and macroalbuminuric diabetic subject had significantly higher levels of systolic and diastolic blood pressure, lipid values and HbA1c. However, when all possible risk factors were tested in a multivariable model, only HbA1c odds ratio [OR] (95% CI) 3,1 (1,1 -9,5) (p < 0,05) and triglycerides [OR] (95% CI) 3,0 (1,7 – 5,4) (p < 0,01) showed a significant correlation to microalbuminuria. In logistic regression, variables independently related to macroalbuminuria were systolic blood pressure[OR] (95% CI) 3,4 (1,5 – 7,8) (p < 0,01) and HbA1c [OR] (95% CI) 4,4 (1,1 – 4,7) (p < 0,05) Conclusions: In childhood-onset (T1DM) after 20 years of diabetes, the only poor glycemic control and hypertension are main risk factors of macroalbuminuria, whereas inadequate glycemic control and dyslipidemia are main risk factors of microalbuminuria.

Characterizing multivariate decoding models based on correlated EEG spectral features

ObjectiveMultivariate decoding methods are popular techniques for analysis of neurophysiological data. The present study explored potential interpretative problems with these techniques when predictors are correlated. MethodsData from sensorimotor rhythm-based cursor control experiments was analyzed offline with linear univariate and multivariate models. Features were derived from autoregressive (AR) spectral analysis of varying model order which produced predictors that varied in their degree of correlation (i.e., multicollinearity). ResultsThe use of multivariate regression models resulted in much better prediction of target position as compared to univariate regression models. However, with lower order AR features interpretation of the spectral patterns of the weights was difficult. This is likely to be due to the high degree of multicollinearity present with lower order AR features. ConclusionsCare should be exercised when interpreting the pattern of weights of multivariate models with correlated predictors. Comparison with univariate statistics is advisable. SignificanceWhile multivariate decoding algorithms are very useful for prediction their utility for interpretation may be limited when predictors are correlated.

Fourier Transform Infrared Spectroscopic Imaging and Multivariate Regression for Prediction of Proteoglycan Content of Articular Cartilage

Fourier Transform Infrared (FT-IR) spectroscopic imaging has been earlier applied for the spatial estimation of the collagen and the proteoglycan (PG) contents of articular cartilage (AC). However, earlier studies have been limited to the use of univariate analysis techniques. Current analysis methods lack the needed specificity for collagen and PGs. The aim of the present study was to evaluate the suitability of partial least squares regression (PLSR) and principal component regression (PCR) methods for the analysis of the PG content of AC. Multivariate regression models were compared with earlier used univariate methods and tested with a sample material consisting of healthy and enzymatically degraded steer AC. Chondroitinase ABC enzyme was used to increase the variation in PG content levels as compared to intact AC. Digital densitometric measurements of Safranin O –stained sections provided the reference for PG content. The results showed that multivariate regression models predict PG content of AC significantly better than earlier used absorbance spectrum (i.e. the area of carbohydrate region with or without amide I normalization) or second derivative spectrum univariate parameters. Increased molecular specificity favours the use of multivariate regression models, but they require more knowledge of chemometric analysis and extended laboratory resources for gathering reference data for establishing the models. When true molecular specificity is required, the multivariate models should be used.