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Results for “multivariate analysis”

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At least 1,153 records · Page 64Linked to original sources
PubMed2004

Multivariate analysis of risk factors for death following gastric bypass for treatment of morbid obesity.

OBJECTIVE: To identify the factors that increase mortality for either open or laparoscopic Roux-en-Y gastric bypass. SUMMARY BACKGROUND DATA: Perioperative mortality is the most feared outcome of bariatric surgery, reported to occur in between 0.5% and 1.5% of patients. METHODS: The bariatric database at Virginia Commonwealth University was queried for patients who had undergone either an open gastric bypass (O-GBP) or a laparoscopic gastric bypass (L-GBP). A multivariate logistic regression analysis to identify factors related to perioperative mortality was performed. Factors examined included age, gender, body mass index, preoperative weight, hypertension, diabetes mellitus, sleep apnea, obesity hypoventilation syndrome, venous stasis ulcers, intestinal leak, small bowel obstruction, and pulmonary embolus. RESULTS: Since 1992, more than 2000 patients had either an O-GBP (n = 1431) or a L-GBP (n = 580). Of the O-GBP, 547 patients had a proximal GBP (P-GBP) and 884 superobese (body mass index > 50 kg/m) patients had a long-limb GBP (LL-GBP). The differences in patient demographics, complications, and perioperative mortality rates between L-GBP and O-GBP and P-GBP and LL-GBP patients were examined. Overall, the independent risk factors associated with perioperative death included leak, pulmonary embolus, preoperative weight, and hypertension. CONCLUSIONS: The risk factors for perioperative death can be separated into patient characteristics and complications. The access method, open versus laparoscopic, was not independently predictive of death, but the operation type, proximal versus long limb, was predictive. The data do not suggest that superobese patients should not undergo surgery, as they are high risk for early death due to their body weight and comorbidities without surgery. Surgery should not be reserved as a desperate last measure for weight loss.

Adolescent↗
PubMed2001

Recurrent infective endocarditis: a multivariate analysis of 21 years of experience. arenzul@tin.it.

BACKGROUND: To evaluate which variables predict recurrence of endocarditis after surgical treatment, we reviewed our 21-year experience. METHODS: Between January 1979 and May 2000, 308 consecutive valve replacement procedures for infective endocarditis were performed in 271 patients. Univariate and multivariate time-related analyses were performed to retrospectively evaluate the role of the following variables in the development of recurrent postoperative endocarditis: gender, site of endocarditis, previous valve disease, drug abuse, diabetes, positive valve/blood cultures, sepsis, perivalvular involvement, previous embolic events, type of replacement device, and persistent postoperative fever. RESULTS: Clinical and echocardiographic follow-up was 97.36% complete, mean follow-up time was 53.2+/-3.4 months. Recurrent endocarditis developed in 58 cases (22.5%). Variables predicting recurrence were prosthetic endocarditis (p = 0.00001), positive valve culture (p = 0.0039), and persistence of fever at the seventh postoperative day (p = 0.000001). CONCLUSIONS: Correct protocols of antibiotic therapy guided by microbiology may reduce the incidence of recurrent endocarditis to allow for surgery on sterile tissues and to prevent prosthetic infection. Recurrence rate is not affected by the choice of valve substitute, but can be prevented by complete surgical debridement.

Adolescent↗
PubMed2006

The prognostic value of hemoglobin change after initiating androgen-deprivation therapy for newly diagnosed metastatic prostate cancer: A multivariate analysis of Southwest Oncology Group Study 8894.

BACKGROUND: The objective of this study was to characterize changes in hemoglobin (HGB) levels after the initiation of androgen-deprivation therapy (ADT) in patients with previously untreated, metastatic prostate cancer who were enrolled in a large clinical trial. METHODS: The multivariate associations between 3-month change in HGB and baseline characteristics were evaluated with a linear regression model. The associations between 3-month change in HGB level and time-to-event outcomes, including overall survival and progression-free survival, were evaluated by using proportional hazards regression models. RESULTS: Quartiles of baseline HGB levels were < or =12.0 g/dL, from 12.1 to 13.7 g/dL, from 13.8 to 14.7 g/dL, and >14.7 g/dL. Overall, 3 months after initiating ADT, the mean HGB level declined 0.54 g/dL (standard deviation [SD], 1.68 g/dL); however, the mean HGB level increased by 0.99 g/dL (SD, 1.83 g/dL) in patients who had baseline HGB levels <12 g/dL and decreased 1.04 g/dL (SD, 1.28 g/dL) in patients who had baseline HGB levels > or =12 g/dL. After adjusting for potential confounders, including baseline HGB level, a decline in HGB after 3 months of ADT was associated independently with shorter survival (hazards ratio [HR], 1.10 per 1 g/dL decline; P = .0035) and shorter progression-free survival (HR, 1.08 per 1 g/dL decline; P = .013). An unexpected finding was that the effect of baseline HGB on overall and progression-free survival varied significantly by race. CONCLUSIONS: In a sample of men with newly diagnosed, metastatic prostate cancer, a decline in HGB level after 3 months of ADT was associated with shorter survival and progression-free survival after adjusting for disease status and other baseline covariates. Although race alone was not a strong predictor of death or disease progression, the effect of the baseline HGB level on overall and progression-free survival varied significantly by race.

Aged↗
PubMed1998

Prognostic relevance of histologic grading, the cell cycle-associated antigen Ki-S1 and cell cycle regulators in malignant fibrous histiocytomas: a multivariate analysis.

The main aim of this study was to compare the prognostic impact of different histologic grading systems, the expression of the cell cycle-associated antigen DNA-topoisomerase-II-alpha (Ki-S1) and the expression of cell cycle regulators in malignant fibrous histiocytomas (MFH) using multivariate analyses. Paraffin-embedded tissue of 161 cases of MFH were studied immunohistochemically for the expression of the proliferation marker Ki-S1, cell cycle regulators (p53, MDM2, waf-1, pRb, p16) and the oncoprotein EGFR. The percentage of immunolabelled tumor cells (index) was assessed. The histologic grade was determined by the two-level grading systems of Costa, Tsujimoto and Pezzi, by the three-level grading systems of Coindre and Van Unnik and by the grading system presented here. Univariate analyses using the LOG rank test showed that all of the applied grading systems produce highly significant differences in survival between the grades of malignancy. Multivariate analyses with COX regression demonstrated that only the grading system presented here, based on the parameters necroses, mitoses and cellularity, had independent prognostic relevance. Moreover, the inclusion of the proposed grading system, the Ki-S1-index and a prognostic index primarily based on the expression of cell cycle regulators into the COX regression was suited for predicting survival in MFH. The grading system presented shows considerable advantages over the grading systems compared in this study for use in the routine pathology of MFH. The prognostic power of the proposed grading system can be enhanced by the combined study of cell cycle regulators and Ki-S1.

Adolescent↗
PubMed2003

Multivariate analysis of the prognostic determinants of the depressor response to exercise therapy in patients with essential hypertension.

This study investigated the contribution of hemodynamic and humoral factors to the variation in the depressor responses to exercise therapy and the significance of the baseline values of these factors in predicting the depressor response of essential hypertensives to mild exercise therapy. Patients with mild to moderate essential hypertension (n=122, F/M: 97/25) performed a bicycle ergometer exercise at a workload equivalent to the lactate threshold for 10 weeks. In all of the patients, systolic and diastolic blood pressures (BP) significantly decreased after 1 week of exercise, continued to decrease until 4 weeks, and were stable from 4 weeks to 10 weeks. Changes in the plasma volume and humoral factors during the study did not differ significantly between responders and non-responders. A multiple logistic regression analysis showed that higher baseline mean BP (MBP) was significantly associated with a poor depressor response (odds ratio 1.84, p=0.002). A variance component analysis indicated that baseline MBP accounted for only 11.2% of the total variance of the depressor response. In conclusion, these summarized results showed that variations in the depressor response to mild exercise therapy were partly determined by baseline MBP, but not by humoral factors, suggesting the possible involvement of other factors, including genetic factors.

Anaerobic Threshold↗
PubMed1994

The use of ultrasonography and Doppler in the prediction of fetal haemolytic anaemia: a multivariate analysis.

OBJECTIVE: To assess the value of ultrasonography and Doppler to predict the severity of fetal haemolytic anaemia. DESIGN: Ultrasonographic measurements of the fetal liver, spleen, umbilical vein and placenta, and Doppler measurements of umbilical venous and fetal aorta flow velocities were performed before the first intrauterine blood transfusion. Multivariate regression models for the prediction of the fetal haemoglobin level were derived from the measurements. SETTING: National referral centre for management of alloimmunised pregnancies. SUBJECTS: Forty fetuses in 39 severe red cell alloimmunised pregnancies. RESULTS: A logistic regression model, incorporating the two Doppler parameters only, predicted the presence or absence of severe anaemia in nonhydropic fetuses with an accuracy of 90%. Positive predictive value was 89% and negative predictive value was 100%. CONCLUSION: In severe red cell alloimmunised pregnancies, Doppler blood flow velocity studies can be used to predict the severity of fetal anaemia. This may lead to a reduction of invasive diagnostic tests, to more accurate timing of intrauterine transfusions, and thus to a higher survival rate.

Anemia, Hemolytic↗
PubMed2005

Arterial compression of the retro-olivary sulcus of the medulla in essential hypertension: a multivariate analysis.

OBJECTIVE: Pulsatile arterial compression (AC) of the ventrolateral medulla (VLM) has been postulated to cause neurogenically mediated essential hypertension (EHTN). We aimed to establish whether the association between AC of specifically the retro-olivary sulcus (ROS) of the VLM and EHTN was significant, while controlling for other risks associated with EHTN. DESIGN: Case-control study. METHODS: Posterior fossa magnetic resonance imaging scans of 131 subjects, including 58 subjects with EHTN and 73 normotensives, were reviewed to determine the presence of AC in the ROS. The history of other risk factors for EHTN was obtained by reviewing medical records. RESULTS: Multivariate logistic regression analysis of these data shows a significant association between AC in the ROS (right and/or left) and EHTN [odds ratio (OR) = 3.03, 95% confidence interval (CI) = 1.30, 7.06]. This analysis was done controlling for other known EHTN risk factors such as age, race, sex, diabetes, and obesity. A secondary analysis also controlling for these variables shows that AC of both the right and left ROS are independently associated with EHTN (right AC: OR = 5.04, 95% CI = 1.33, 19.17; left AC: OR = 3.39, 95% CI = 1.20, 9.60). CONCLUSIONS: In this retrospective study of subjects with EHTN and normotensive controls that had undergone magnetic resonance imaging of the posterior fossa, AC of the ROS on either side of the medulla is a significant independent risk factor in EHTN. Further studies are required to determine whether this is true for the general population of patients with neurogenically mediated EHTN.

Adult↗
PubMed2000

Variations in GP nursing home patient workload: results of a multivariate analysis.

The number of old people living in UK nursing homes has increased substantially over the past 15 y. There is evidence that such patients generate larger workloads for primary carers than do those of similar age and sex living in their own homes. Clearly, any extra workload involved in providing primary care services to nursing home patients, needs to be reflected in the resources afforded general practitioners (GPs) who are tasked with its provision. By the same token variations in workloads between patients need to be examined and explained for any insights these might provide on funding issues. To examine and explain variations in GP workload associated with nursing home patients and determine the implications of these for GP funding, a 12 month case control study of all nursing home residents over 65 y old registered with nine general practices was undertaken. A multivariate regression analysis was used to examine variations in GP workload associated with 270 nursing home patients. Multivariate regression models explaining the variation in workload cost per month in terms of the GP practice delivering care and patients age and sex had little explanatory power (R(2)=0.07). A fuller method including the patient's Barthel score and initial diagnosis as additional explanatory variables added little to the explanatory power of the model (R(2)=0.12). The ability of the multivariate models used here to explain the variation in GP workload was poor. GPs may require an allowance to compensate for differences in workload associated with nursing home patients but adjusting these payments for differences in age, sex, initial diagnosis or the other variables included in this analysis would not appear to be supported.

Aged↗
PubMed1998

Prognosis of Japanese encephalitis: a multivariate analysis.

To evaluate the role of various clinical neurophysiological laboratory and radiological parameters in the prognosis of Japanese encephalitis (JE), 28 patients were prospectively evaluated. Their age ranged between two and 54 years, with eight of them being female and 11 children. The outcome was defined, at the end of a six-month period, as being poor (bed-ridden), partial (partial dependence for activity for daily life) and complete recovery (independent for activities of daily life). A number of clinical (age, degree of coma, decerebration or decortication and reflex changes), laboratory (CSF cell and protein content, and haemagglutination inhibition titre in the serum), neurophysiological (EEG, EMG, sensory and motor evoked potentials) and the extent of radiological changes were subjected to stepwise multivariate logistic regression analysis. By the end of six months, four patients had died, seven had poor, ten partial and seven had complete recovery. The best set of predictors of outcome included age, Glasgow coma scale and reflex changes.

Adolescent↗
PubMed1992

Rapid multivariate analysis and display of cross-reacting antibodies on human leukocytes.

We present an application which can rapidly determine the binding patterns of monoclonal antibodies on mixed populations of cells simultaneously in a single rapid analysis. It is an application of the tube identifier parameter (TIP) system which can provide fully correlated list-mode data of the entire patient phenotype in a single file. Using the phenogram analytical display, we are able to determine the cross-reacting antibodies for an entire antibody panel for each cell type. This information can be displayed in a single plot. Using light scatter gating to select different populations of lymphocytes, monocytes, and neutrophils, phenograms can be simultaneously generated. This provides a directly comparable means of displaying the positive and negative binding characteristics of each antibody on each cell population. Any marker combination that is abnormal will be identifiable in the phenogram. Additionally, by plotting the fluorescence distributions of each marker beside one another (termed overview), quantifiable differences in intensity can be determined. There are 3 major benefits of the proposed analysis. By using the TIP concept, several sets of antibodies can be compared simultaneously. Any light scatter gate can be used and this gate can be changed on one histogram or plot, yet apply to the total analysis. Data analysis is particularly rapid since the entire phenotype of a patient can be evaluated by performing a single rapid analysis.

Antibodies↗