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Results for “multivariate analysis”

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PubMed2000

Hyperhomocysteinemia in liver transplant recipients: prevalence and multivariate analysis of predisposing factors.

Liver transplant recipients have an increased risk for cardiovascular disease because of a high incidence of obesity, arterial hypertension, diabetes mellitus, and hyperlipidemia. Hyperhomocysteinemia has been found to be an important risk factor for cardiovascular disease in large studies. Fasting serum levels of homocysteine were measured in 105 liver transplant recipients, and hyperhomocysteinemia was defined as a fasting serum homocysteine level greater than 13 micromol/L. Patients with versus without hyperhomocysteinemia were compared. The possible association of hyperhomocysteinemia with age, sex, cause of liver disease, time elapsed since liver transplantation, immunosuppressive therapy, folic acid level, liver function test results, renal function, and other cardiovascular risk factors was investigated. Patients with serum homocysteine levels greater than 15 micromol/L were treated with folic acid, 10 mg/d, and serum homocysteine levels were measured again 1 to 3 months later in 10 patients. Hyperhomocysteinemia was detected in 28 patients (27%). In univariate analysis, it was associated with hepatitis C virus infection, treatment with mycophenolate mofetil, and greater serum levels of alkaline phosphatase, gamma-glutamyl transpeptidase, urea, and creatinine. In multivariate analysis, only greater serum levels of creatinine (P =.006) were associated with hyperhomocysteinemia. Treatment with folic acid resulted in a decrease in fasting serum homocysteine levels in 9 of the 10 patients tested (P =.01). Hyperhomocystinemia, associated with renal dysfunction, is a frequent finding in liver transplant recipients. Treatment with folic acid may reduce fasting homocysteine levels.

Creatinine↗

PubMed1996

Multivariate analysis of factors affecting waiting time to heart transplantation.

BACKGROUND: The growing clinical success of cardiac transplantation has resulted in a dramatic increase in the number of patients referred and subsequently listed for cardiac transplantation. Paradoxically, in the presence of a limited donor organ pool, such expansion has increased both the waiting time for transplantation and the number of patients dying while on the waiting list. METHODS: We performed univariate and multivariate analyses of the waiting times of 301 patients listed for transplantation using a Cox proportional hazards model to evaluate the simultaneous effect of multiple variables on the waiting time of heart transplant candidates. Variables considered included age, sex, race, blood type, weight at listing, United Network for Organ Sharing (UNOS) status at listing, UNOS status at transplantation, and proportion of time on the waiting list as UNOS status 1. RESULTS: The mean waiting time for patients ultimately having transplantation was 170.2 +/- 206.0 days; the median waiting time was 103.5 days. Age, sex, weight, blood type, and percent of time as UNOS status 1 all had a significant impact on waiting time in the univariate analysis. By multivariate analysis, proportion of time as UNOS status 1, lower weight at listing, and blood type AB were all highly associated as predictors of a shorter waiting time. Weight at listing represented a continuous variable whose risk ratio for a shorter waiting time correlated in such a way that the risk of a longer waiting time increased 2.3 per 22.5-kg (50-pound) increase in weight. Blood types A and B, although associated with a shorter waiting time, correlated less strongly than the other three variables. CONCLUSIONS: Our findings from this multivariate analysis demonstrate that UNOS status, blood type, and weight were the variables that most strongly affected overall waiting time for transplantation. It is our hope to define more accurately a group of patients with both a high likelihood of a long waiting time and a prohibitive risk of death while on the waiting list, who therefore may benefit from surgical alternatives to transplantation.

ABO Blood-Group System↗

PubMed1997

Discrimination of fibroblast subtypes by multivariate analysis of gene expression.

Fibroblasts and myofibroblasts from normal, fibrotic or tumoral breast tissues present multiple quantitative differences in gene expression even when grown in isolation. We were therefore prompted to investigate whether one could recognize various subtypes by their constitutive-gene expression profile. Quantitative autoradiographic data for 34 constitutively expressed transcripts were submitted to multivariate analysis of variance, followed by discriminant analysis and single linkage cluster analysis. Models assuming up to 8 putative fibroblast subtypes (among fibroblasts or myofibroblasts from breast skin, normal mammary stroma, tumor-adjacent "normal" stroma, post-radiation fibrosis lesions and benign or malignant tumors) and an epithelial-cell group used as an internal control resulted in 100% correct classification. Myofibroblasts from various origins clustered close to, although distinctly apart from, their corresponding alpha-smooth-muscle-actin-negative counterparts. Malignant tumor fibroblasts were phenotypically more distant from normal cells compared with other pathological types. Our results support the hypothesis of co-adaptive transformation of stromal and epithelial tissues during breast tumoral development and suggest that different types of fibroblasts give rise to different types of myofibroblasts. Discriminant analysis of quantitative molecular variation may be considered for the development of a powerful artificial-intelligence method for cell typing and should be particularly useful when no reliable discrete molecular markers are available.

Breast↗

PubMed2003

Predictive factors of progression of chronic renal insufficiency: a multivariate analysis.

The purpose of this study was to identify clinical, nutritional, and laboratory factors associated with the rate of progression of chronic renal insufficiency among children and adolescents admitted to a pre-end-stage renal failure (ESRF) interdisciplinary program. Sixty-two children and adolescents aged 2 months to 19 years with chronic renal failure on conservative management were prospectively followed from 1990 to 1999. The following variables were analyzed: age at admission, sex, race, blood pressure, primary renal disease, Z scores for weight and height, glomerular filtration rate (GFR), urea, and presence and degree of proteinuria. Progression to ESRF was assigned as a dependent variable. The analysis was conducted in two steps. In a univariate analysis, variables associated with ESRF outcome were identified by the log-rank test. Then, the variables that were significantly associated with adverse outcome were included in a multivariate analysis. This analysis, using the Cox proportional hazards model, was performed to identify variables that were independently associated with a worse prognosis. Only variables that remained independently associated with adverse outcome were included in the final model. Twenty-one (34%) patients evolved to ESRF during a median follow-up of 43 months. Two variables were identified as independent predictors of progression to ESRF: GFR under 30 ml/min (RR=3, 95% CI=1.7-5.3, P=0.0001) and severe proteinuria (RR=3.1, 95% CI=1.2-7.6, P=0.01). The combination of two factors-GFR lower than 30 ml/min and presence of severe proteinuria on admission-was an independent indicator of adverse outcome in children and adolescents with chronic renal insufficiency who were conservatively managed.

Adolescent↗

PubMed2004

Prognostic value of anemia in newly diagnosed metastatic prostate cancer: a multivariate analysis of southwest oncology group study 8894.

PURPOSE: Previously reported association of anemia with shorter survival in newly diagnosed metastatic prostate cancer may simply reflect extent of disease. The impact of anemia on response to androgen deprivation is not known. We examined the prognostic value of anemia in a multivariate analysis that included disease extent and other tumor and demographic covariates in 957 patients starting hormonal therapy for metastatic prostate cancer as part of Southwest Oncology Group study 8894. MATERIALS AND METHODS: The multivariate associations of disease and patient measures with anemia (hemoglobin less than 12 gm/dl) were evaluated with a logistic regression model. The associations between hemoglobin and survival and progression-free survival (PFS) were evaluated using a proportional hazards model, and included indicators for quartiles of hemoglobin and baseline covariates. Prostate specific antigen (PSA) normalization (PSAN, or PSA of 4 ng/ml or less) was evaluated with a logistic model. RESULTS: Quartiles of hemoglobin were 10.1 or less, 10.2 to 12.0, 12.1 to 13.4 and greater than 13.4 gm/dl. In a multivariate model anemia was significantly associated (p <0.02) with being black, performance status 2 to 3 (vs 0 to 1), extensive disease and higher PSA. Anemia was inversely associated with prior therapy with curative intent and with Gleason score 6 to 7 (vs 5 or less), and was not associated with age or bone pain. After adjusting for potential confounders, lower hemoglobin was associated with shorter survival and PFS, and lower likelihood of PSAN with hormonal therapy (p <0.01). CONCLUSIONS: In this newly diagnosed metastatic prostate cancer sample, anemia was common and was associated with shorter survival, shorter PFS, and lower likelihood of PSAN with hormonal therapy after adjustment for disease status and other covariates.

Aged↗

PubMedDate not supplied

Gentamicin nephrotoxicity: application of multivariate analysis.

A retrospective study was conducted to identify patient risk factors associated with gentamicin nephrotoxicity using multivariate analysis. Patients were evaluated for nephrotoxicity using an algorithm that considers serum creatinine, previous general experience with the drug, alternative etiologic candidates, timing of events, drug concentrations or evidence of overdosage, dechallenge, and rechallenge. There were 220 patients who met the criteria for inclusion in the study (103 men and 117 women). Variables found not to be significant discriminators between toxic and nontoxic patients included height, weight, sex, dose, estimated peak gentamicin concentration, age, and initial renal function. Variables that were found to enter into the discriminant analysis included presence of complicating factors with nephrotoxic potential, number of concurrent potentially nephrotoxic drugs, intensity index or estimated trough gentamicin concentration, and the total dose or treatment duration. Two models were developed; the probability of correctly classifying a patient as toxic was 63.5% and 65.4%, and as nontoxic was 72.1% and 68.8% for the two models, respectively. Although the discriminant models developed were statistically significant, the discrimination between toxic and nontoxic patients was not satisfactory to allow development of a generalized predictive model. Multivariate techniques were found to be essential in allowing for the differentiation of variables causing gentamicin nephrotoxicity.

Adult↗

PubMed1998

Omasal anatomy in New Zealand red and fallow deer: an exploratory multivariate analysis.

We measured the weight and volume of omasae, and the number, weight and area of omasal laminae from wild fallow (Cervus dama), and wild and farmed red deer (Cervus elaphus) whose diet, as indicated by rumen content, was known. A multivariate analysis yielded two principal components, interpreted as indices of overall omasal size and laminar leafiness. The second component showed significantly greater variance in wild red deer than in farmed red or wild fallow deer. Deer feeding on a mixed diet of browse and grasses may have greater variability of omasal from than those feeding on grass alone. A relationship is derived by which the laminar area can be estimated from counts of laminae in different size classes.

Animals↗

PubMed2004

Evaluation of the combined solar TiO2/photo-Fenton process using multivariate analysis.

The effect of combining the photocatalytic processes using TiO2 and the photo-Fenton reaction with Fe3+ or ferrioxalate as a source of Fe2+ was investigated in the degradation of 4-chlorophenol (4CP) and dichloroacetic acid (DCA) using solar irradiation. Multivariate analysis was used to evaluate the role of three variables: iron, H2O2 and TiO2 concentrations. The results show that TiO2 plays a minor role when compared to iron and H2O2 in the solar degradation of 4CP and DCA in the studied conditions. However, its presence can improve TOC removal when H2O2 is totally consumed. Iron and peroxide play major roles, especially when Fe(NO3)3 is used in the degradation of 4CP. No significant synergistic effect was observed by the addition of TiO2 in this process. On the other hand, synergistic effects were observed between FeOx and TiO2 and between H2O2 and TiO2 in the degradation of DCA.

Chlorophenols↗

PubMed2004

Metabolic fingerprinting of wild type and transgenic tobacco plants by 1H NMR and multivariate analysis technique.

The metabolomic analysis of wild type and constitutive salicylic acid producing tobacco plants (CSA tobacco, Nicotiana tabacum 'Samsun' NN) plants overexpressing salicylate biosynthetic genes was carried out by 1H NMR spectrometry and multivariate analysis techniques. The principle component analysis (PCA) of the 1H NMR spectra showed a clear discrimination between those samples by PC1 and PC2. The discrimination of non-inoculated, TMV-virus inoculated, and systemic leaves or veins could also be obtained by PCA analysis. Major peaks in 1H NMR spectra contributing to the discrimination were assigned as those of chlorogenic acid, malic acid, and sugars. This method allows an efficient differentiation between wild type and transgenic plants without any pre-purification steps.

Chlorogenic Acid↗

PubMed1991

The natural history of multiple sclerosis: a geographically based study. 3. Multivariate analysis of predictive factors and models of outcome.

A multivariate hierarchical analysis was used to assess the significance of several demographic and clinical factors in multiple sclerosis patients. We used the time to reach level 6 on the disability status scale (DSS) of Kurtzke as endpoint. Several factors at presentation were significantly associated with an adverse outcome including older age at onset, male sex, cerebellar involvement or insidious onset of a motor deficit as first symptom. Factors ascertained later which were associated significantly with a worse outcome, even after controlling for those previously mentioned, included persisting deficits in brainstem, cerebellar or cerebral systems, a higher frequency of attacks in the first 2 yrs after onset of disease, a short first interattack interval and higher DSS at 2 yrs and 5 yrs from onset. An analysis similar to multiple regression was used to generate predictive models which permit the calculation of the median time to DSS 6 for patients with a given set of covariates. The goodness of fit of these models to the data and their predictive accuracy are discussed.

Adult↗

PubMed2005

Nausea and dizziness after vestibular schwannoma surgery: a multivariate analysis of preoperative symptoms.

OBJECTIVE: Nausea and dizziness are very discomforting for patients after vestibular schwannoma surgery and they impair recovery. METHODS: To identify preoperative symptoms and conditions that increase the risk of development of nausea after vestibular schwannoma surgery, a multivariate analysis was performed. One hundred fifteen patients with vestibular schwannoma had a microsurgical tumor removal in a standardized procedure in 2001 and 2002. Eighteen patients were excluded from the study because of previous surgery (recurrent tumors, 7 patients) or bilateral tumor occurrence (neurofibromatosis, 11 patients). Analysis was performed regarding postoperative amount of antiemetic medication, vomiting, and subjective feeling of the patient. Tumor grading, body mass index, sex, previous complaints, examination at admission, and side of the tumor were taken in consideration. RESULTS: Women had significant longer postoperative complaints (mean, 3.0 d; standard error, 0.47) and needed longer antiemetic therapy (mean, 3.3 d; standard error, 0.49) than men (mean, 1.72 d; standard error, 0.21). Patients developing no significant postoperative complaints were all in the higher tumor grading group, Grades 3a, 4a, and 4b. There was a significant difference in the duration of antiemetic therapy between tumors graded 1 and tumors graded 3 or 4. Patients with a positive stepping test preoperatively had a tendency to demand less antiemetic medication. Women with small tumors are most likely to develop significant complaints after vestibular schwannoma surgery. CONCLUSION: It is possible to identify patients with a higher risk of postoperative nausea and dizziness after vestibular schwannoma surgery. This allows one to inform these patients preoperatively and to initiate an early postoperative drug therapy to ease their symptoms.

Adult↗

PubMed1999

Factors associated with blood loss and blood product transfusions: a multivariate analysis in children after open-heart surgery.

UNLABELLED: In this prospective cohort study of 548 children undergoing open-heart surgery, we evaluated demographic and perioperative factors to identify variables associated with perioperative blood loss and blood product transfusions. Using multivariate analysis, younger patient age was found to be the variable most significantly associated with bleeding and transfusions. Higher preoperative hematocrit, complex surgery, lower platelet count during cardiopulmonary bypass (CPB), and longer duration of deep hypothermic circulatory arrest were also significantly associated with bleeding and transfusion. Excessive postoperative chest tube (CT) drainage was associated with intraoperative bleeding. Independently associated variables accounted for 76% of the variability in CT output measured after 2 h in intensive care. Patients were subdivided into children aged < or =1 yr (infants) and children >1 yr; infants bled more intraoperatively (P<0.005); had greater cumulative CT output at 2, 6, 12, and 24 h (P<0.0001); and received more blood products (P<0.0001). Factors associated with bleeding and transfusions varied with patient age. Lower body core temperature during CPB was highly associated with blood loss and transfusions in infants, whereas resternotomy, preoperative congestive heart failure, and prolonged duration of CPB were significant factors associated with bleeding and transfusions in children >1 yr old. IMPLICATIONS: Knowledge of the factors associated with blood loss and blood product transfusions can help to identify children at risk of excessive bleeding after open-heart surgery.

Blood Component Transfusion↗

PubMed2004

Ischemic arterial complications after liver transplantation in the adult: multivariate analysis of risk factors.

HYPOTHESIS: To minimize the incidence of ischemic arterial complications, risk factors should be clearly identified. Knowledge of the predisposing factors for such complications would make possible the institution of strict surveillance protocols that could ensure early detection of complications and so prevent the progression of ischemic damage to graft failure. DESIGN: Retrospective univariate and multivariate analysis. SETTING: University hospital. PATIENTS: Six hundred fifty-three adults who underwent 747 orthotopic liver transplantations. MAIN OUTCOME MEASURES: We used univariate and multivariate analyses to retrospectively assess the role of possible risk factors for early and late HA thrombosis (HAT) and stenosis (HAS), including etiology of liver disease, donor and recipient sex and age (aged < or =60 vs >60 years), cause of donor death, preservation solution, cold ischemic time, previous orthotopic liver transplantation, HA back-table reconstruction, direct arterial anastomosis vs interpositional conduit, experience of the surgeon, intraoperative transfusion requirements, acute rejection, and cytomegalovirus infection. RESULTS: We observed 58 ischemic complications, including 26 early HAT, 13 late HAT, and 19 HAS. Independent predictors of early HAT were donor age greater than 60 years and bench reconstruction of anatomical variants of the HA; of late HAT, arterial anastomosis fashioned using an interpositional graft of donor iliac artery (iliac conduit) and donors who died of cerebrovascular accident; and of HAS, previous orthotopic liver transplantation and cytomegalovirus infection. CONCLUSIONS: Predisposing factors for HAT mostly stem from donor and graft features. Use of iliac conduits should be limited, particularly when using old donors. Frequent screening of the arterial flow to the graft with Doppler ultrasonography is advisable in patients at risk.

Arterial Occlusive Diseases↗

PubMed1992

Prognostic factors of hepatic encephalopathy after portacaval anastomosis: a multivariate analysis in 50 patients.

Portacaval anastomosis has proved to be effective in avoiding active and recurrent hemorrhage from gastroesophageal varices in liver cirrhosis. However, hepatic encephalopathy is the most common and serious complication of this procedure. The aim of this study was to investigate by multivariate analysis the predictive factors of development of hepatic encephalopathy in 50 Child's A and B cirrhotic patients whose variceal bleeding was treated with emergency (n = 17) or elective (n = 33) portacaval anastomosis. The etiology of the cirrhosis was alcoholic in 74% of cases. The mean follow-up was 22.7 +/- 16.6 months (range 1-60 months). The 2-yr probability of suffering from at least one episode of hepatic encephalopathy in the overall group was 43%. The multivariate analyses (Cox's regression method) of 37 variables based upon clinical history, physical examination, and laboratory data disclosed that only five of these variables had independent predictive value: need for diuretic treatment in the days prior to surgery, absence of hepatomegaly, and serum levels of total bilirubin, gamma-globulin, and hemoglobin. According to the contribution of each one of these factors to the final model, a prognostic index was obtained which allowed the division of patients in two different groups of risk for developing hepatic encephalopathy (20% and 74%, respectively, after 2 yr of surgery; p = 0.0002). This index may help to better choose those candidates for portacaval anastomosis.

Adult↗

PubMedDate not supplied

Potential biological markers for the staging of tumor progression in oral mucosa: a multivariate analysis.

A recent trend in cancer control programmes is the development of early detection strategies and chemoprevention of premalignant lesions. The present study evaluates the potential of selected markers in the biological staging of tumor progression in oral mucosa for better management of the disease. The expression patterns of various cytokeratin protein types such as 10/11, 13 & 16, 19, 18, 14 and pancytokeratin, involucrin, ras p21, epidermal growth factor (EGF) and its receptor (EGFR) were assessed immunohistochemically in various stages of tumor progression in oral mucosa. Statistical analyses such as the Kruskal-Wallis one-way ANOVA, Spearman's rank correlation and multiple regression analysis were carried out to see which proteins have a significant association with tumor progression in oral mucosa. Statistical analysis showed that the expression patterns of cytokeratin types 10/11, 14 and 19, involucrin and epidermal growth factor were significantly correlated with tumor progression in oral mucosa in both univariate and multivariate analysis. Thus the biological stage of a lesion can be calculated from the multiple regression equation derived for these proteins, which could be more useful in assessing the stage of tumor progression in oral mucosa than histopathological grading.

Biomarkers, Tumor↗

PubMed1993

Risk factors for early mortality in allogeneic bone marrow transplantation. A multivariate analysis on 174 leukaemia patients.

Allogeneic bone marrow transplantation in patients with leukaemia is an aggressive therapeutic procedure which implies high early mortality. Current opinion trends attribute the greater part of the procedure toxicity to the preparative regimen. The results of a multivariate analysis on data of 174 leukaemia patients conditioned with total body irradiation (TBI), 10-12 Gy, single dose or fractionated, and lung shielding at 8 Gy, plus chemotherapy: cyclophosphamide 120 mg/kg, before or after TBI, are presented. The variables statistically related with early mortality are age, Karnofsky index (KI) and acute graft-versus-host disease (GvHD). No variable depending on radiotherapy reached the significance level. The relative risk of early mortality for patients older than 26 years, in bad general condition (KI < 90%), or developing acute severe (grades II-IV)GvHD, is 3.99, 5.68, and 6.71, respectively. We conclude that in the range of TBI schedules analysed, radiation therapy is not an important factor in early death, but acute severe GvHD, or recipient's bad general condition are factors to be improved by bone marrow transplantation teams if they want to improve the therapeutic index of the procedure.

Adolescent↗

PubMed2000

Multivariate analysis of factors influencing physical work capacity in wheelchair-dependent paraplegics with spinal cord injury.

The purpose of this study was to determine the main factors that influence physical work capacity (PWC) in wheelchair-dependent paraplegics with spinal cord injury (SCI) using multivariate analysis. Thirty-two male paraplegics with SCI (PSCI) performed a submaximal arm exercise test on an arm-cranking ergometer to determine their PWC (oxygen uptake: ml x kg(-1) x min(-1)) at a heart rate of 150 beats x min(-1) (PWC150). Hayashi's Quantification first type was applied to analyze the effects on PWC150 of six factors: age, smoking, level of physical activity, occupation, level of SCI and period since SCI. This analysis revealed high partial correlation coefficients between PWC150 and the level of SCI (0.651) and physical activity level (0.583) compared to other factors. In addition, the multiple correlation coefficient for six factors in predicting PWC150 was 0.726. These results indicate that the level of SCI and physical activity are the most important factors in determining PWC in wheelchair-dependent male PSCI.

Adult↗

PubMed1990

[Multivariate analysis for the understanding of typical diabetic hemostasis criteria. 3. Determination of a typical retinopathy parameter-constellation].

Features of metabolism and haemostasis which are different in diabetics of both types in comparison with normal subjects were covered by the statistical method of multivariance analysis depending on the severity of diabetic retinopathy. In 29 diabetics without retinopathy, 46 patients with stage I or II, and 36 patients with stage III the following parameters could be found as optimal criteria for characterizing the extent of vascular changes: blood sugar concentration, concentration of sialic acid and HDL cholesterol in the serum, serum protein, sialic acid per protein volume, total cholesterol in the serum and capillary fragility and number of large spreading forms of platelets features of hemostasis. Thus, diabetic retinopathy is characterized by a wide spectrum of different features containing the parameters of hemostasis. Thrombocytic vascular interactions are characterized by platelet spreading and capillary fragility which are significant for the development of diabetic retinopathy.

Biomarkers↗