Multivariate Regression: Additional Topics

2007 ◽  
pp. 494-525
Keyword(s):  
Multivariate Regression

scholarly journals Development of dose-response functions for historic paper degradation using exposure to natural conditions and multivariate regression

2019 ◽  
Vol 168 ◽  
pp. 108944 ◽  
Author(s):  
Gianluca Pastorelli ◽  
Shuo Cao ◽  
Irena Kralj Cigić ◽  
Costanza Cucci ◽  
Abdelrazek Elnaggar ◽  
...  
Keyword(s):  
Dose Response ◽  
Multivariate Regression ◽  
Response Functions ◽  
Natural Conditions ◽  
Paper Degradation ◽  
Historic Paper

Use of Damage Control and the Open Abdomen in Combat

2013 ◽  
Vol 79 (8) ◽  
pp. 747-753 ◽  
Author(s):  
Benjamin Bograd ◽  
Carlos Rodriguez ◽  
Richard Amdur ◽  
Fred Gage ◽  
Eric Elster ◽  
...  
Keyword(s):  
Length Of Stay ◽  
Multivariate Regression ◽  
Injury Severity ◽  
Open Abdomen ◽  
Damage Control ◽  
Unit Length ◽  
Significant Risk ◽  
Hospital Length Of Stay ◽  
Study Cohort ◽  
Regression Analyses

Despite the well-documented use of damage control laparotomy (DCL) in civilian trauma, its use has not been well described in the combat setting. Therefore, we sought to document the use of DCL and to investigate its effect on patient outcome. Prospective data were collected on 1603 combat casualties injured between April 2003 and January 2009. One hundred seventy patients (11%) underwent an exploratory laparotomy (ex lap) in theater and comprised the study cohort. DCL was defined as an abbreviated ex lap resulting in an open abdomen. Patients were stratified by age, Injury Severity Score (ISS), Glasgow Coma Score (GCS), mechanism of injury, and blood product administration. Multivariate regression analyses were used to determine risks factors for intensive care unit length of stay (ICU LOS), hospital length of stay (HLOS), and the need for DCL. Mean age of the cohort was 24 ± 5 years, ISS was 21 ± 11, and 94 per cent sustained penetrating injury. Patients with DCL comprised 50.6 per cent (n = 86) of the study cohort and had significant increases in ICU admission ( P < 0.001), ICU LOS ( P < 0.001), HLOS ( P < 0.05), ventilator days ( P < 0.001), abdominal complications ( P < 0.05), but not mortality ( P = 0.65) compared with patients without DCL. When compared with the non-DCL group, patients undergoing DCL required significantly more blood products (packed red blood cells, fresh-frozen plasma, platelets, and cryoprecipitate; P < 0.001). Multivariate regression analyses revealed blood transfusion and GCS as significant risk factors for DCL ( P < 0.05). Patients undergoing DCL had increased complications and resource use but not mortality compared with patients not undergoing DCL. The need for combat DCL may be different compared with civilian use. Prospective studies to evaluate outcomes of DCL are warranted.

scholarly journals 222 Partitioning of retained energy between protein and fat gain, and heat of product formation and support metabolism in growing beef cattle

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 158-158
Author(s):  
Phillip A Lancaster
Keyword(s):  
Linear Regression ◽  
Mixed Models ◽  
Multivariate Regression ◽  
Literature Search ◽  
Energy Use ◽  
Random Variable ◽  
Product Formation ◽  
Metabolizable Energy ◽  
Overall Efficiency ◽  
Metabolizable Energy Intake

Abstract Multiple linear regression inaccurately computes the efficiency of energy use for protein and fat gain. The objective was to quantify efficiency of metabolizable energy use for protein and fat gain along with heats of product formation and support metabolism. A literature search was performed to compile data (31 studies, 214 treatment means) on metabolizable energy intake (MEI) and composition of empty body gain in growing steers and heifers. Data analyses were performed using R statistical package for mixed models with study as random variable. Linear regression of MEI on energy gain (EG; P &lt; 0.001; R2 = 0.627) resulted in an estimate of metabolizable energy for maintenance (MEm) of 156 kcal/kg.75 and efficiency of ME use for gain of 0.518. Linear regression of MEI on EG as protein and fat (P &lt; 0.001; R2 = 0.623) resulted in an estimate of MEm of 149 kcal/kg.75, and efficiency of protein (kp) and fat (kf) gain of 0.274 and 0.585, respectively, resulting in an overall efficiency of EG of 0.520. Nonlinear regression model (EG = kg*(MEI-MEm)) resulted in an estimate of MEm of 103 kcal/kg.75 and efficiency of EG of 0.342. The heat of product formation was assumed to be 0.48 (1 – 0.52) and the heat of support metabolism (HiEv) 0.18 (0.52 – 0.34). Multivariate regression was used to fit simultaneous models for EG as protein (EGp = (kp+HiEvp)*k*MEA) and fat (EGf = (kf+(0.18-HiEvp))*(1-k)*MEA). Estimates (P &lt; 0.001) of kp and kf were 0.12 ± 0.01 and 0.63 ± 0.02, and HiEvp and proportion of ME available for protein gain (k) were 0.11 ± 0.01 and 0.75 ± 0.01, respectively. The heat of product formation and support metabolism for protein were 0.77 and 0.11, and fat were 0.30 and 0.07, respectively. In conclusion, efficiency of ME use for protein was lesser than for fat gain, and heat of support metabolism was greater for protein than fat gain.

scholarly journals 1574. Multivariate Regression Analysis to Determine Independent Predictors of Treatment Outcomes in the RESTORE-IMI 2 Trial

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S785-S786
Author(s):  
Robert Tipping ◽  
Jiejun Du ◽  
Maria C Losada ◽  
Michelle L Brown ◽  
Katherine Young ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Clinical Response ◽  
Treatment Outcomes ◽  
Multivariate Regression ◽  
Multivariate Regression Analysis ◽  
Apache Ii Score ◽  
Double Blind ◽  
Mitt Population ◽  
Study Results ◽  
All Cause Mortality

Abstract Background In the RESTORE-IMI 2 trial, imipenem/cilastatin/relebactam (IMI/REL) was non-inferior to PIP/TAZ for treating hospital-acquired/ventilator-associated bacterial pneumonia (HABP/VABP) in the primary endpoint of Day 28 all-cause mortality (D28 ACM) and the key secondary endpoint of clinical response (CR) at early follow-up (EFU; 7-14 d after end of therapy). We performed a multivariate regression analysis to determine independent predictors of treatment outcomes in this trial. Methods Randomized, controlled, double-blind, phase 3, non-inferiority trial comparing IMI/REL 500 mg/250 mg vs PIP/TAZ 4 g/500 mg, every 6 h for 7-14 d, in adult patients (pts) with HABP/VABP. Stepwise-selection logistic regression modeling was used to determine independent predictors of D28 ACM and favorable CR at EFU, in the MITT population (randomized pts with ≥1 dose of study drug, except pts with only gram-positive cocci at baseline). Baseline variables (n=19) were pre-selected as candidates for inclusion (Table 1), based on clinical relevance. Variables were added to the model if significant (p &lt; 0.05) and removed if their significance was reduced (p &gt; 0.1) by addition of other variables. Results Baseline variables that met criteria for significant independent predictors of D28 ACM and CR at EFU in the final selected regression model are in Fig 1 and Fig 2, respectively. As expected, APACHE II score, renal impairment, elderly age, and mechanical ventilation were significant predictors for both outcomes. Bacteremia and P. aeruginosa as a causative pathogen were predictors of unfavorable CR, but not of D28 ACM. Geographic region and the hospital service unit a patient was admitted to were found to be significant predictors, likely explained by their collinearity with other variables. Treatment allocation (IMI/REL vs PIP/TAZ) was not a significant predictor for ACM or CR; this was not unexpected, since the trial showed non-inferiority of the two HABP/VABP therapies. No interactions between the significant predictors and treatment arm were observed. Conclusion This analysis validated known predictors for mortality and clinical outcomes in pts with HABP/VABP and supports the main study results by showing no interactions between predictors and treatment arm. Table 1. Candidate baseline variables pre-selected for inclusion Figure 1. Independent predictors of greater Day 28 all-cause mortality (MITT population; N=531) Figure 2. Independent predictors of favorable clinical response at EFU (MITT population; N=531) Disclosures Robert Tipping, MS, Merck & Co., Inc. (Employee, Shareholder) Jiejun Du, PhD, Merck & Co., Inc. (Employee, Shareholder) Maria C. Losada, BA, Merck & Co., Inc. (Employee, Shareholder) Michelle L. Brown, BS, Merck & Co., Inc. (Employee, Shareholder) Katherine Young, MS, Merck & Co., Inc. (Employee, Shareholder)Merck & Co., Inc. (Employee, Shareholder) Joan R. Butterton, MD, Merck & Co., Inc. (Employee, Shareholder) Amanda Paschke, MD MSCE, Merck & Co., Inc. (Employee, Shareholder) Luke F. Chen, MBBS MPH MBA FRACP FSHEA FIDSA, Merck & Co., Inc. (Employee, Shareholder)Merck & Co., Inc. (Employee, Shareholder)

scholarly journals Placenta previa with posterior extrauterine adhesion: clinical features and management practice

BMC Surgery ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yoshikazu Nagase ◽  
Shinya Matsuzaki ◽  
Masayuki Endo ◽  
Takeya Hara ◽  
Aiko Okada ◽  
...  
Keyword(s):  
Propensity Score ◽  
Blood Loss ◽  
Cesarean Delivery ◽  
Clinical Features ◽  
Surgical Outcomes ◽  
Multivariate Regression ◽  
Placenta Previa ◽  
Control Group ◽  
Intraoperative Blood Loss ◽  
Intraoperative Bleeding

Abstract Background A diagnostic sign on magnetic resonance imaging, suggestive of posterior extrauterine adhesion (PEUA), was identified in patients with placenta previa. However, the clinical features or surgical outcomes of patients with placenta previa and PEUA are unclear. Our study aimed to investigate the clinical characteristics of placenta previa with PEUA and determine whether an altered management strategy improved surgical outcomes. Methods This single institution retrospective study examined patients with placenta previa who underwent cesarean delivery between 2014 and 2019. In June 2017, we recognized that PEUA was associated with increased intraoperative bleeding; thus, we altered the management of patients with placenta previa and PEUA. To assess the relationship between changes in practice and surgical outcomes, a quasi-experimental method was used to examine the difference-in-difference before (pre group) and after (post group) the changes. Surgical management was modified as follows: (i) minimization of uterine exteriorization and adhesion detachment during cesarean delivery and (ii) use of Nelaton catheters for guiding cervical passage during Bakri balloon insertion. To account for patient characteristics, propensity score matching and multivariate regression analyses were performed. Results The study cohort (n = 141) comprised of 24 patients with placenta previa and PEUA (PEUA group) and 117 non-PEUA patients (control group). The PEUA patients were further categorized into the pre (n = 12) and post groups (n = 12) based on the changes in surgical management. Total placenta previa and posterior placentas were more likely in the PEUA group than in the control group (66.7% versus 42.7% [P = 0.04] and 95.8% versus 63.2% [P < 0.01], respectively). After propensity score matching (n = 72), intraoperative blood loss was significantly higher in the PEUA group (n = 24) than in the control group (n = 48) (1515 mL versus 870 mL, P < 0.01). Multivariate regression analysis revealed that PEUA was a significant risk factor for intraoperative bleeding before changes were implemented in practice (t = 2.46, P = 0.02). Intraoperative blood loss in the post group was successfully reduced, as opposed to in the pre group (1180 mL versus 1827 mL, P = 0.04). Conclusions PEUA was associated with total placenta previa, posterior placenta, and increased intraoperative bleeding in patients with placenta previa. Our altered management could reduce the intraoperative blood loss.

scholarly journals Abatacept in rheumatoid arthritis-associated interstitial lung disease: short-term outcomes and predictors of progression

2021 ◽  
Author(s):  
Marika Tardella ◽  
Marco Di Carlo ◽  
Marina Carotti ◽  
Andrea Giovagnoni ◽  
Fausto Salaffi
Keyword(s):  
Rheumatoid Arthritis ◽  
Interstitial Lung Disease ◽  
Lung Disease ◽  
Multivariate Regression ◽  
Clinical Laboratory ◽  
Smoking Habit ◽  
Concomitant Treatment ◽  
Current Smoking ◽  
Modifiable Factors ◽  
Aba Response

Abstract Introduction Interstitial lung disease in rheumatoid arthritis (RA-ILD) is an extra-articular involvement that impairs the prognosis and for which there is still no well-coded treatment. The aim of this study was to evaluate abatacept (ABA) effectiveness and safety in patients with RA-ILD. Methods RA-ILD patients who started ABA treatment were consecutively enrolled. Chest high-resolution computed tomography (HRCT), clinical, laboratory and respiratory function variables were collected at baseline and after 18 months of ABA treatment. HRCT abnormalities were evaluated using a computer-aided method (CaM). ABA response was established based on the change in the percentage of fibrosis evaluated at HRCT-CaM, dividing patients into “worsened” (progression ≥ 15%), “improved” (reduction ≥ 15%), and “stable” (changes within the 15% range). The multivariate regression model was used to assess the associations between RA characteristics and ABA response. Results Forty-four patients (81% women, mean age 59.1 ± 8.0, mean disease duration of 7.5 ± 3.1 years) were studied. Five patients (11.4%) showed RA-ILD progression, 32 patients (72.6%) were considered stable, and 7 patients (16.0%) showed an RA-ILD improvement. The proportion of current smokers was significantly different between “worsened” patients, respect to those defined as "improved/stable” (p = 0.01). Current smoking habit (p = 0.005) and concomitant methotrexate treatment (p = 0.0078) were the two variables related to RA-ILD progression in multivariate regression analysis. Conclusion Treatment with ABA is associated with a RA-ILD stability or improvement in the 88.6% of patients. Current smoking habit and concomitant treatment with methotrexate are the modifiable factors associated with RA-ILD worsening. Key Points• Abatacept plays a favourable role in the control of RA-ILD, with a significant worsening in only 11.4% of patients during a 18-month follow-up period.• The predictive variables related to RA-ILD progression during abatacept therapy are the concomitant treatment with methotrexate and current smoking habit.

Epicardial fat thickness as arterial hypertension predictor in normotensive patients with abdominal obesity

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
T Kuznetsova ◽  
M Druzhilov
Keyword(s):  
Blood Pressure ◽  
Regression Analysis ◽  
Blood Glucose ◽  
Waist Circumference ◽  
Arterial Hypertension ◽  
Multivariate Regression ◽  
Fasting Blood Glucose ◽  
Multivariate Regression Analysis ◽  
Epicardial Fat Thickness ◽  
Fat Thickness

Abstract Objective Arterial hypertension (HTN) is one of the most common diseases associated with obesity. Visceral obesity (VO) with dysfunctional visceral adipose tissue plays the main role in obesity induced HTN. Direct criteria of VO including echocardiographic epicardial fat thickness (EFT) may become an additional predictor of HTN. Purpose The aim was to assess the role of echocardiographic EFT (EEFT) as a predictor of HTN in normotensive patients with abdominal obesity (AO). Methods 526 normotensive men (according to ambulatory blood pressure monitoring (ABPM) without therapy) with AO (waist circumference (WC) &gt;94 cm) and SCORE &lt;5%, without cardiovascular diseases and diabetes mellitus were examined (age 45.1±5.0 years). The lipid and glucose profiles, creatinine, uric acid and C-reactive protein blood levels, albuminuria evaluation, echocardiography, carotid ultrasound, bifunctional ABPM were performed. The values of EEFT ≥75 percentile for persons 35–45 years and 46–55 years were 4.8 mm and 5.8 mm respectively. These values used as epicardial VO criteria. Patients with subclinical carotid atherosclerosis due to the lipid-lowering therapy administration (n=98) were excluded from the follow-up. Re-examination with ABPM was conducted on average through 46.3±5.1 months. Data were summarized as mean ± standard error, statistical analysis conducted with paired two-tailed t-tests, Pearson χ2 criterion and multivariate regression analysis. Results Data of 406 persons were available for analysis. HTN as average daily blood pressure ≥130/80 mm Hg was detected in 157 (38.7%) patients. These patients were characterized by initially higher values of age (45.9±4.6 years vs 44.3±4.9 years, p&lt;0.001), waist circumference (106.9±7.3 cm vs 104.2±7.3 cm, p&lt;0.001), body mass index (BMI) (32.0±3.3 kg/m2 vs 30.9±3.2 kg/m2, p&lt;0.001), average daily systolic and diastolic blood pressure (120.7/74.5±4.6/3.4 mm Hg vs 118.2/73.2±5.5/3.9 mm Hg, p&lt;0.001), EEFT (5.2±0.7 mm vs 4.4±1.0 mm, p&lt;0.001). The epicardial VO was initially detected in 95 (23.3%) patients. In patients with HTN the initial prevalence of epicardial VO was greater (58.0% vs 23.3%, p&lt;0.001). As predictors for the multivariate regression analysis the clinical and laboratory examinations data and EEFT were evaluated. According to the results a mathematical model for estimating the probability HTN was obtained: 0.696*fasting blood glucose + 0.198*systolic BP + 2.844*EFT – 40.166 (constant). Among these predictors EEFT was characterized by the highest standardized regression coefficient (0.302, p&lt;0.001) (0.295, p&lt;0.01 for fasting blood glucose, 0.035, p&lt;0.001 for systolic BP). The Hosmer-Lemeshow test value was 0.863, the total percentage of correct classifications was 86%, the area under the ROC-curve was 0.913. Conclusions EEFT (4.8 mm for persons 35–45 years and 5.8 mm for persons 46–55 years) may be an additional predictor of HTN in normotensive patients with AO. Funding Acknowledgement Type of funding source: None

scholarly journals Regional medical practice variation in high-cost healthcare services

2021 ◽  
Author(s):  
Michael Berger ◽  
Thomas Czypionka
Keyword(s):  
Medical Practice ◽  
Regional Variation ◽  
Multivariate Regression ◽  
Healthcare Services ◽  
Practice Variation ◽  
District Level ◽  
Healthcare Data ◽  
Regional Medical ◽  
Mri Scans ◽  
Magnetic Resonance Imaging Mri

AbstractMagnetic resonance imaging (MRI) is a popular yet cost-intensive diagnostic measure whose strengths compared to other medical imaging technologies have led to increased application. But the benefits of aggressive testing are doubtful. The comparatively high MRI usage in Austria in combination with substantial regional variation has hence become a concern for its policy makers. We use a set of routine healthcare data on outpatient MRI service consumption of Austrian patients between Q3-2015 and Q2-2016 on the district level to investigate the extent of medical practice variation in a two-step statistical analysis combining multivariate regression models and Blinder–Oaxaca decomposition. District-level MRI exam rates per 1.000 inhabitants range from 52.38 to 128.69. Controlling for a set of regional characteristics in a multivariate regression model, we identify payer autonomy in regulating access to MRI scans as the biggest contributor to regional variation. Nevertheless, the statistical decomposition highlights that more than 70% of the regional variation remains unexplained by differences between the observable district characteristics. In the absence of epidemiological explanations, the substantial regional medical practice variation calls the efficiency of resource deployment into question.

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