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Results for “multivariate analysis”

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PubMed2003

Factors affecting mortality in generalized postoperative peritonitis: multivariate analysis in 96 patients.

Mortality of generalized postoperative peritonitis remains high at 22% to 55%. The aim of the present study was to identify prognostic factors by means of univariate and multivariate analysis in a consecutive series of 96 patients. Mortality was 30%. Inability to clear the abdominal infection or to control the septic source, older age, and unconsciousness were significant factors related to mortality in the multivariate analysis. Failure to control the peritoneal infection (15%) was always fatal and correlated with failed septic source control, high Acute Physiology and Chronic Health Evaluation (APACHE) II score, and male gender. Failure to control the septic source (8%) also was always fatal and correlated with high APACHE II score and therapeutic delay. In patients with immediate source control, residual peritonitis occurred in 9% after purulent or biliary peritonitis and in 41% after fecal peritonitis ( p = 0.002). In patients without immediate control of the septic source, delayed control was still achieved in 100% after a planned relaparotomy (PR) strategy versus 43% after an on-demand relaparotomy (ODR) strategy ( p = 0.018). In the same patients, mortality was 0% in the PR group versus 64% in the ODR group ( p = 0.007). Early relaparotomy is related to improved septic source control. After relaparotomy for generalized postoperative peritonitis, a PR strategy is indicated whenever source control is uncertain. It also might decrease mortality in fecal peritonitis. An ODR approach is adequate for purulent and biliary peritonitis with safe septic source control.

Adolescent↗

PubMed1980

Evaluation by multivariate analysis of changes in systolic time intervals during exercise in the supine and upright positions.

In this study multivariate analysis was adopted to establish how simultaneous changes in heart rate (HR), blood pressure (BP) and work load (W) can affect systolic time intervals (STI). Thus, 13 normal volunteers underwent two consecutive exercise stress tests in the supine and upright position on a bicycle ergometer. By multivariate analysis it was shown that, while in the supine position left ventricular ejection time (LVET) is influenced by HR and W (LVET) = 330.6 - 0.76 HR - 0.41 W, F = 224, P is less than 0.001), in the upright position LVET changes are due only to HR variations (LVET = 309 - 0.88 HR, P is less than 0.001). Pre-ejection period (PEP) in both positions is related to HR and W, but this latter has a non-linear influence (supine: PEP = 110.9 - 0.15 HR -0.34 W + 0.0012 W(2), F = 56.4, P is less than 0.001; upright: PEP = 119 - 0.16 HR - 0.5 W + 0.0025 W(2), F = 86.7, P is less than 0.001). Finally, PEP/LVET ratio is correlated both in the supine and upright position with maximal BP, HR and W; however, the influence of HR and BP is different in the two positions (supine: PEP/LVET = 0.259 + 0.00047 BP + 0.00068 HR - 0.00167 W + 0.000013 W(2), F = 5.68, P is less than 0.01; upright: PEP/LVET = 0.201 + 0.0011 HR - 0.00371 W + 0.00016 W(2), F = 4.79, P is less than 0.01).

Adolescent↗

PubMedDate not supplied

Clinical stage I and II endometrial carcinoma: multivariate analysis of prognostic factors.

In 221 patients with FIGO stage I and II endometrial carcinoma, the impact on survival of age at diagnosis, menopausal status, FIGO stage, myometrial invasion, tumor grade and histology was evaluated by univariate and multivariate analysis. At a median follow-up of 50 months (range 45-210), 42 patients had died, and therefore overall survival was 81% (179/221). Univariate analysis showed that age, menopausal status and histology did not influence survival, whereas FIGO stage, myometrial invasion and tumor grade were important prognostic factors. Multivariate analysis showed that tumor grade had a significant and independent impact on survival and confirmed that FIGO stage is the most important parameter influencing survival.

Actuarial Analysis↗

PubMed1999

[Statistical analysis of localized non-Hodgkin's lymphomas of the head and neck--multivariate analysis of prognostic factors and evaluation of therapeutic modalities].

Prognostic factors and treatment outcome of 48 patients with Stage I (29) or II (19) non-Hodgkin's lymphoma of the head and neck were analyzed retrospectively. There were 26 males and 22 females, aged from 15 to 89 years old, with an average age of 57. The primary lesion was located in Waldeyer's ring in 25 patients, the nasal cavity and paranasal sinuses in 13, cervical lymph nodes in 8, and others in 2. Histologically, 2 had low grade lymphoma, 42 had intermediate grade disease, and 1 had high grade disease. The patients were treated with radiation alone (5 patients), chemotherapy according to a cyclophosphamide, doxorubicin, vincristine, prednisone- (CHOP) regimen (8 patients), or a combination of both treatments (35 patients). In univariate analyses, an unfavorable prognosis was associated with age > or = 60, Stage I disease, and extralymphatic lesion. Multivariate analysis showed that an extralymphatic lesion was a significant independent risk factor for death (p = 0.0093). The overall five-year survival rate was 73.5%. Differences in the treatment was not reflected in the outcome. Our results suggest that a combination of chemotherapy (CHOP) and radiation is an appropriate treatment for lymphatic stage I and II non-Hodgkin's lymphoma of the head and neck. However, more intensive therapy is necessary for patients with extralymphatic head and neck NHL.

Adolescent↗

PubMed1991

Multivariate analysis to simplify the differential diagnosis of broad complex tachycardia.

Univariate analysis has identified several criteria that aid the differential diagnosis of broad complex tachycardia. In this study of 102 consecutive patients multivariate analysis was performed to identify which of 15 clinical and 11 electrocardiographic variables were independent predictors of ventricular tachycardia. These were shown to be a history of myocardial infarction, the QRS waveforms in leads aVF and V1, and a change in axis from sinus rhythm to tachycardia of more than 40 degrees. If none of the criteria was met, the diagnosis was almost certainly supraventricular tachycardia. If one criterion was met the diagnosis was probably supraventricular tachycardia. If two criteria were met then the diagnosis was probably ventricular tachycardia. If three or four criteria were met, the diagnosis was almost certainly ventricular tachycardia. The predictive accuracy was 93%. This was increased to 95% by including two other criteria--definite independent P wave activity and ventricular extrasystoles with the same QRS configuration as that in tachycardia. These criteria were not included in the multivariate analysis because though they were 100% specific they were seldom seen. These four criteria can be used as simple rules in determining the origin of a broad complex tachycardia.

Diagnosis, Differential↗

PubMed1988

Applications of multivariate analysis in diagnostic cytology.

Three multivariate methods for structure simplification (cluster analysis, principal component analysis and factor analysis) and three multivariate methods for prediction (discriminant analysis, analysis of variance and regression analysis) are discussed and contrasted, along with basic descriptive statistics for multivariate data. These methods are only a subset of the multivariate methods currently in use, but include those that have thus far been applied in diagnostic cytology. Multivariate analyses provide a basis for describing and analyzing large complex data sets and, with the enormous amounts of data becoming available, their applications in many areas of diagnostic cytology must surely increase.

Cytological Techniques↗

PubMed1996

Is multivariate analysis of PET data more revealing than the univariate approach? Evidence from a study of episodic memory retrieval.

In a functional imaging study of cued paired associate retrieval, in which the strength of association between pair members was systematically varied, we predicted increased right frontal activity as a function of weakening semantic linkage. An initial univariate analysis found the opposite effect, with greater right frontal activity during recall of strongly linked paired associates. This unexpected result led us to perform a multivariate analysis of covariance (MANCOVA), an approach which proved more informative. This analysis showed that the most significant source of task-related variance was accounted for by a nonlinear relationship not predicted by the prior hypothesis and not revealed by the standard univariate approach. This application of the MANCOVA supports the assertion that multivariate analysis can provide an important adjunct to univariate approaches like statistical parametric mapping (SPM). New perspectives engendered by the MANCOVA still allow for statistical inference but are not constrained by explicit hypotheses about specific task-dependent effects.

Adult↗

PubMed1989

Multivariate analysis of aminoglycoside levels in hemodialysis patients.

Multivariate discriminant analysis was performed on data for 50 consecutive hemodialysis patients who had received aminoglycoside treatment because of severe bacterial infections. The 10 of the 60 clinical parameters considered to be most important were survival of patients (28/50 patients), success of treatment (27/50 patients), acute or chronic renal failure (15 vs. 35), age (54 +/- 17 years), creatinine level (675 +/- 298 mumol/l), artificial ventilation (21/50 patients), need for catecholamines (19/50 patients), continuous arteriovenous hemofiltration (9/50 patients), duration of therapy (12 +/- 8 days) as well as aminoglycoside peak (7.5 +/- 2.7 mg/l) and trough levels (3.6 +/- 1.3 mg/l). The 4 of the 10 parameters investigated by multivariate analysis significantly contributing to survival of patients were clinical success of aminoglycoside treatment (p = 0.0001), no need for catecholamines (p = 0.0001), duration of dosage (p = 0.003) and aminoglycoside peak levels (p = 0.009).

Adolescent↗

PubMed2006

PYCHEM: a multivariate analysis package for python.

UNLABELLED: We have implemented a multivariate statistical analysis toolbox, with an optional standalone graphical user interface (GUI), using the Python scripting language. This is a free and open source project that addresses the need for a multivariate analysis toolbox in Python. Although the functionality provided does not cover the full range of multivariate tools that are available, it has a broad complement of methods that are widely used in the biological sciences. In contrast to tools like MATLAB, PyChem 2.0.0 is easily accessible and free, allows for rapid extension using a range of Python modules and is part of the growing amount of complementary and interoperable scientific software in Python based upon SciPy. One of the attractions of PyChem is that it is an open source project and so there is an opportunity, through collaboration, to increase the scope of the software and to continually evolve a user-friendly platform that has applicability across a wide range of analytical and post-genomic disciplines. AVAILABILITY: http://sourceforge.net/projects/pychem

Algorithms↗

PubMedDate not supplied

Conversion from laparoscopic to open cholecystectomy: multivariate analysis of preoperative risk factors.

BACKGROUND: Laparoscopic cholecystectomy has become the gold standard in the treatment of symptomatic cholelithiasis. Some patients require conversion to open surgery and several preoperative variables have been identified as risk factors that are helpful in predicting the probability of conversion. However, there is a need to devise a risk-scoring system based on the identified risk factors to (a) predict the risk of conversion preoperatively for selected patients, (b) prepare the patient psychologically, (c) arrange operating schedules accordingly, and (d) minimize the procedure-related cost and help overcome financial constraints, which is a significant problem in developing countries. AIM: This study was aimed to evaluate preoperative risk factors for conversion from laparoscopic to open cholecystectomy in our setting. SETTINGS AND DESIGNS: A case control study of patients who underwent laparoscopic surgery from January 1997 to December 2001 was conducted at the Aga Khan University Hospital, Karachi, Pakistan. MATERIALS AND METHODS: All those patients who were converted to open surgery (n = 73) were enrolled as cases. Two controls who had successful laparoscopic surgery (n = 146) were matched with each case for operating surgeon and closest date of surgery. STATISTICAL ANALYSIS USED: Descriptive statistics were computed and, univariate and multivariate analysis was done through multiple logistic regression. RESULTS: The final multivariate model identified two risk factors for conversion: ultrasonographic signs of inflammation (adjusted odds ratio [aOR] = 8.5; 95% confidence interval [CI]: 3.3, 21.9) and age > 60 years (aOR = 8.1; 95% CI: 2.9, 22.2) after adjusting for physical signs, alkaline phosphatase and BMI levels. CONCLUSION: Preoperative risk factors evaluated by the present study confirm the likelihood of conversion. Recognition of these factors is important for understanding the characteristics of patients at a higher risk of conversion.

Adult↗

PubMed1999

Lymphnode metastasis in head and neck squamous cells carcinoma: multivariate analysis of prognostic variables.

Cervical lymphnodes metastatization by the squamous cell carcinoma of the head and neck is well known as a prognostic negative factor as far as survival is concerned. Multivariate analysis has been used on 207 cases of head and neck squamous cell carcinomas (HNSCC) in order to identify the possible prognostic significance of a group of clinical and histopathological characteristics, aiming to find a correlation with the possible occurrence of cervical lymphnodes. Two hundred and seven patients (168 males and 39 females, mean age: 62 years) with SCCHN were studied. They underwent surgery alone and radiotherapeutic associated treatment. Variables regarding the patient, carcinoma and histology were analysed: age, sex, smoking and alcohol consumption, performance status, concomitant internal pathologies (cardiopathies, hepatopathies, broncho-pneumopathies, metabolic disorders), site and size of primary tumor (T stage), number and size of laterocervical lymph node localization (clinical N stage), grading, vascular permeation, perineural infiltration. Multivariate analysis of prognostic factors was performed using BMDP's PLR programme. Some variables showed a great risk of lymphnode metastasis; among sites: supraglottic larynx (p = 0.05), base of the tongue (p = 0.04), hypopharynx (p = 0.05); some histological parameters as lower degree of histological differentiation (p = 0.02), the presence of vascular permeation (p = 0.06) and perineural invasion (p = 0.07) appear to represent predisposing factors for the onset of adenopathies. By considering prognostic factors as shown, it is possible to better identify metastasis risk cases, that leads to improved therapeutical strategies.

Adult↗

PubMed1990

[Preoperative discrimination between benign and malignant ovarian tumors by multivariate analysis].

To obtain a precise preoperative diagnosis of benign and malignant ovarian tumors, multivariate analysis was performed using a combination of tumor markers, diagnostic imagings, clinical findings and epidemiological data. Twenty-eight factors were selected for a discriminant analysis, which included 10 factors for tumor markers, 8 for diagnostic imagings, 4 for clinical features and 6 for epidemiological data. On 235 patients (malignant: 100, benign: 135), the usefulness of the discriminant analysis was evaluated retrospectively. As a results, an accuracy of preoperative discrimination was 82% for a discriminant analysis of tumor markers alone, 91% for diagnostic imagings, 84% clinical findings and 65% for epidemiological data. Twenty-one factors were selected by chi-square test or T-test. When 21 factors were used, the sensitivity and the specificity for the diagnosis of malignant ovarian tumor were 98% and 88% respectively. The results indicate that the discriminant analysis is valuable for preoperative discrimination of patient with ovarian tumors.

Adolescent↗

PubMed1995

Multivariate analysis of prognostic factors in 75 patients with soft tissue sarcoma.

The results of 75 patients with soft-tissue sarcomas treated by the combination of local surgical excision plus postoperative radiotherapy are reported. Thirty-five tumors were situated in the extremities, 32 in the trunk, and eight in the head and neck. Twenty-eight tumors were high grade, 33 intermediate and 14 low grade. Sixty-two patients had complete resections (wide or marginal) and 13 incomplete resections (intralesional). Radiation was administered with a shrinking-field technique (median total dose, 64 Gy; range, 50-78). Twenty-five patients developed local recurrence (33%). The 5-year local control rate was 67%. On univariate analysis, a tumor site other than extremity (p < 0.05), unfavorable histology (p < 0.01), and incomplete resection (p < 0.01) were poor risk factors for local recurrence. When multivariate analysis were performed, only incomplete resection (relative risk (RR) 7.2) remained a poor risk factor. The 5-year overall survival rate was 50.5% for the entire group. Following a univariate analysis of host tumor and treatment-related factors, a tumor site other than extremity (p < 0.05), high tumor grade (p < 0.01) unfavorable histology (p < 0.05), and incomplete tumor resection (p < 0.01) were found to significantly increase the risk of further tumor death. Multivariate analysis found high tumor grade (RR 5.6), and incomplete resection (RR 7) to be independent poor risk factors for survival.

Adult↗

PubMed1999

Multivariate analysis of predictors of cerebral vasospasm occurrence after aneurysmal subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: The role of type of treatment on cerebral vasospasm occurrence after aneurysmal subarachnoid hemorrhage (SAH) has not been studied. Through multivariate analysis we determined the independent prognostic factors of the occurrence of symptomatic vasospasm following aneurysmal SAH in a study cohort of 244 patients undergoing either surgical or endovascular treatment. The prognostic factors of sequelae after aneurysmal SAH were studied as well. METHODS: Symptomatic vasospasm was defined as the association of deterioration in a patient's neurological condition between 3 and 14 days after SAH with no other explanation and an increase in mean transcranial Doppler velocities of >120 cm/s. The prognostic factors were registered on admission and during the intensive care stay. RESULTS: Symptomatic vasospasm occurred in 22.2% surgical patients compared with 17.2% endovascular treatment patients (P=0.37). Multivariate analysis revealed that the probability of occurrence of symptomatic vasospasm decreased with age >50 years (relative risk [RR], 0.47 [0.25 to 0.88]) and severe World Federation of Neurological Surgeons (WFNS) grade measured on admission (RR, 0.43 [0.20 to 0.90]) and increased with hyperglycemia occurring during the intensive care stay (RR, 1.94 [1.04 to 3.63]). No difference in risk of symptomatic vasospasm could be identified between surgical and endovascular treatment. Symptomatic vasospasm (OR, 4.73 [CI, 1. 77 to 12.6]) as well as WFNS grade of >2 (OR, 8.95 [3.46 to 23.2]), treatment complications (OR, 8.39 [3.16 to 22.3]), and secondary brain insults were associated with an increased risk of 6-month sequelae. CONCLUSIONS: Age <50 years, good neurological grade, and hyperglycemia were all associated with an increased risk of cerebral vasospasm whereas treatment was not. This provides a basis for future clinical prospective randomized trials comparing both treatments.

Adult↗

PubMed1992

The prognosis of medical coma in Ibadan: results of multivariate analysis.

During a recent prospective investigation of 116 children with medical coma in Ibadan, 52 (45%) survived intact, 23 (20%) developed residual neurological deficits and the remaining 41 (35%) died. This series is concerned with the use of multivariate analysis in predicting outcome of medical coma in an individual patient, based mostly on clinical information (27 variables) obtained within 12 hours of admission. Stepwise logistic regression analysis revealed that only 17 of the 27 variables have independent significance in predicting outcome. When discriminant analysis was performed on these 17 variables so as to obtain a classification function of outcome (survived intact, survived with deficits and dead), 92% of the cases were correctly classified. Eight children were, however, seriously misclassified. These were four intact survivors and four dead cases who were classified as dead and survived without neurological sequelae, respectively. These results suggest that multivariate analysis of clinical and laboratory information obtained in the comatose state can provide predictive information.

Adolescent↗

PubMed1989

[The prognosis of thrombocytopenic purpura using predictive criteria evaluation by multivariate analysis methods].

The development of predictive systems with the resources of multivariate analysis let us to do gradually a more objective medicine. In this study we correlate a set of characteristics observed in 39 patients with thrombocytopenic purpura during the first week of medical treatment against the score of severity of the whole purpuric disorder, evaluated a the 25 week of evolution. It was accomplished with a model of multiple logistic regression of successive steps which let us to get the weights of each one of the indicants in order to predict the severity of the whole hemorrhagic diathesis. Probably the more significative indicants of severity are intracranial bleeding, profuse nasal and vaginal bleeding, profuse petechial bleeding and the presence of hematomas.

Adolescent↗

PubMed1999

Prognostic factors and relative risk for survival in N1-3 oral squamous cell carcinoma: a multivariate analysis using Cox's hazard model.

The records of 136 patients with N1-3 oral squamous cell carcinoma treated by surgery were investigated retrospectively, with the aim of finding out which factors were predictive of survival on multivariate analysis. Four independent factors significantly influenced survival in the following order: pN stage; T stage; histological grade; and N stage. The most significant was pN stage, the five-year survival for patients with pN0 being 91% and for patients with pN1-3 41%. A further study was carried out on the 80 patients with pN1-3 to find out their prognostic factors for survival and the independent factors identified by multivariate analysis were T stage and presence or absence of extracapsular spread to metastatic lymph nodes.

Adult↗

PubMed1991

A multivariate analysis of risk factors for preeclampsia.

OBJECTIVE: --To determine, in a multivariate analysis, risk factors for preeclampsia that could be observed early in pregnancy and to establish whether these risk factors are different for nulliparas and multiparas. DESIGN: --A case-control study of preeclampsia. SETTING: --Women who gave birth at Northern California Kaiser Permanente Medical Centers in 1984 and 1985. PARTICIPANTS: --Preeclamptic cases (n = 139) were determined from discharge diagnosis of severe preeclampsia and by confirmation of blood pressures and proteinuria from medical records. Controls (n = 132) were randomly selected women who had no discharge diagnosis of any hypertensive disorder of pregnancy and who had no evidence of hypertension or proteinuria from medical record review. MAIN VARIABLES EXAMINED: --Medical records were abstracted for information regarding maternal age, race, previous pregnancy history, family medical history, socioeconomic status, employment during pregnancy, body mass, and smoking and alcohol consumption. RESULTS: --Multiple logistic regression analyses confirmed that case patients were more likely than control patients to be nulliparous (adjusted odds ratio [OR], 5.4; 95% confidence interval [Cl], 2.8 to 10.3) and that preeclampsia in a previous pregnancy greatly increased the risk in a subsequent one (adjusted OR, 10.8; 95% Cl, 1.2 to 29.1). However, regardless of parity, preeclamptic women were also more likely to be of high body mass (adjusted OR, 1.7; 95% Cl, 1.2 to 6.2), to work during pregnancy (adjusted OR, 2.1; 95% Cl, 1.1 to 4.4), and to have a family history of hypertension (adjusted OR, 1.7; 95% Cl, 0.92 to 3.2). Having a previous history of a spontaneous abortion was protective but only in multiparous women (adjusted OR for multiparas, 0.09; 95% Cl, 0.02 to 0.48). In contrast, being black was a significant risk for preeclampsia but only in nulliparous women (adjusted OR for nulliparas, 12.3; 95% Cl, 1.6 to 100.8). CONCLUSIONS: --There are a number of risk factors for preeclampsia that may be determined early in a woman's pregnancy. Multiparas and nulliparas share certain risk factors but not others. A cohort investigation is needed to determine the ability of these risk factors to predict who develops preeclampsia.

Adult↗