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Results for “multivariate analysis”

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PubMed1975

The ascent of man: deductions based on a multivariate analysis of the brain.

This paper attempts to investigate taxonomic and phylogenetic relationships through an analysis of the distribution of mass within the brain. A multivariate analysis was performed on encephalization ratios for various divisions of the brain, employing volume measurements reported for 63 species by Stephan et al. [1970]. The ratios for each brain region were considered to lie along one of the dimensions of eight dimensional 'brain space', and distances between all species were calculated and employed in the determination of 'family trees'. It was assumed that modern species have, in many cases, brains representative of different stages of an evolutionary progression towards higher encephalization, and it was assumed that no 'backwards evolution' occurred. The family trees based on these data and assumptions were rigidly determined and do not represent mere opinion but, rather, inescapable conclusions if one accepts the premises. Most of the findings were in very good agreement with traditional or popular ideas, and this includes conclusions that tree shrews were ancestral to prosimians and that simians are derived from a tarsioid ancestor. Other findings, however, were just as strikingly deviant from current popular and expert thought. Present methods demanded, for example, that man must have a platyrrhine ancestry. While one may reject this particular conclusion it remains true that by present measures the human brain is much more like that of an American wooley or spider monkey than like that of either the chimpanzee or the gorilla.

Amygdala↗

PubMed1995

Surgical strategy for patients with gastric carcinoma with submucosal invasion. A multivariate analysis.

BACKGROUND: Early gastric cancer can be treated by endoscopic excision or simple wedge surgical resection. Standard gastrectomy often is advised if submucosal invasion is found, even though only 15-25% of these patients have lymph node metastases. In this study, the risk of lymph node involvement was examined by multivariate analysis to develop a simple discriminant function for surgical decision making in this setting. METHODS: The authors determined factors significantly correlated with lymph node involvement in a retrospective review of 196 patients with gastric adenocarcinoma invading into, but not beyond, the submucosa. Depth and horizontal spread of cancer in the submucosa were evaluated in addition to ordinary pathologic factors. Discriminant analysis for lymph node involvement was performed using explanatory variables chosen from the results of the univariate analyses. RESULTS: Lymph node involvement correlated significantly with larger tumor size; greater dimension of submucosal invasion; deeper submucosal invasion; gross appearance of Type I, IIc + III or IIa + IIc; and severity of vessel invasion. Of the variables, the amount of lymphatic invasion, macroscopic appearance, and maximum dimension of submucosal infiltration were selected as effective predictors of lymph node involvement according to discriminant analysis. A correct discrimination of 74.8% was obtained with a linear discriminant function using these variables. Lymph node involvement was observed in 50% of the cases with a discriminant score less than -1 and in 25% of those with a score between -1 and 0, whereas no lymph node involvement was observed in those with a score greater than 2. CONCLUSIONS: Discriminant function as used in this study provided a useful criterion for additional surgery for patients with gastric carcinoma invading the submucosa who were treated initially by localized excision. Prophylactic lymph node dissection may not be necessary for a discriminant score greater than 2, whereas extended lymphadenectomy would be recommended for a score less than -1.

Adenocarcinoma↗

PubMed2001

Risk factors suggesting malignant transformation of gastric adenoma: univariate and multivariate analysis.

BACKGROUND AND STUDY AIMS: Since gastric adenomas are precancerous lesions, polypectomy is necessary. However, there have been no reports suggesting factors capable of predicting malignant transformation of gastric adenomas removed by endoscopic snare polypectomy (ESP) or endoscopic mucosal resection (EMR) in Korea, a country in which gastric cancer is a major problem. The aim of this paper was to elucidate the risk factors suggesting malignant transformation of gastric adenomas removed by ESP or EMR at our center. PATIENTS AND METHODS: Between November 1994 and June 1999, 118 gastric adenomas diagnosed on the basis of endoscopy and histological examinations of the forceps biopsy specimens obtained were treated by ESP or EMR at our department. Factors capable of predicting malignancy were searched for in the endoscopy reports, still photographs, and histopathological findings. RESULTS: Eight of the 118 adenomas ultimately proved to have malignant foci. In the univariate analysis, four of the variables studied--location, histological type, surface redness, and degree of dysplasia--had a statistically significant relationship with malignant transformation. In the multivariate analysis, only the degree of dysplasia had a statistically significant relationship with malignant transformation. CONCLUSIONS: These results suggest that a diagnosis of high-grade dysplasia in forceps biopsy material should be considered an absolute indication for ESP or EMR.

Adenoma↗

PubMed1991

A single institution's experience with solitary pancreas transplantation: a multivariate analysis of factors leading to improved outcome.

The results of cadaveric donor pancreas transplantation at a single institution using the bladder drainage technique have been analyzed according to several factors that may impinge on outcome. Both multivariate and univariate statistical methods were used, with emphasis on solitary (pancreas after kidney and pancreas transplant alone) as opposed to simultaneous pancreas/kidney transplants. Of the 444 pancreas transplants performed at our institution from December 1966 through December 1991, we analyzed 249 bladder-drained cadaver donor pancreas transplants from November 1984 through August 1991. The factors that had a significant impact on outcome in the Cox multivariate analysis included retransplantation, age, preservation time, and degree of HLA mismatching. The results of solitary pancreas transplants improved with time as the factors that have an impact on graft survival rates were deliberately manipulated. During the 1988 to 1991 era, pancreas graft functional survival (insulin-independent) rates were not significantly different among the 3 recipient categories. Solitary pancreas transplant recipients less than 45 years old receiving primary grafts had a 1-year function rate of 61% in the pancreas transplant alone group (n = 32) and 74% in the pancreas after kidney group (n = 24). By placing emphasis on minimizing HLA mismatches, by giving adequate immunosuppression, and by detecting and treating rejection episodes early based on a decline in urine amylase, the results with solitary pancreas transplantation can be as good as those with simultaneous pancreas kidney transplantation. There are limitations to the interpretations that can be given to retrospective studies using inhomogeneous factors, as is the case in the analyses presented here. We cannot identify risk factors with certainty because the protocols changed over time, eg, immunosuppressive regimens, policies on HLA matching, and choice of duct-management techniques. Thus, in the analysis of all cases, not only was there a higher proportion by the bladder-drainage techniques in the later period, but the proportion of cases with good HLA matches was also higher: yet the earlier cases (more poorly matched, performed by the other techniques, and with worse results), were in the model. Retransplantation is also a problem for the analysis. The number performed was proportionately greater in the later period, and the possibility of retransplantation differed according to the patient's age. Over such a long time, we cannot evaluate our gain in experience statistically.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1999

Risk factors of hepatitis C virus infection in patients on hemodialysis: a multivariate analysis based on a dialysis register in Central Italy.

A seroprevalence survey of antibodies to HCV was carried out among 2788 hemodialysis (HD) patients in a region of central Italy. Anti-HCV seroprevalence was 28.6%. A multivariate analysis of risk factors showed a significant association with time on HD, history of blood transfusion and metropolitan area of residence. Our study clearly showed that HCV infection is common among HD patients and is partially associated with preventable factors.

Adolescent↗

PubMed1989

[Multivariate analysis of acute leukemia].

The outcome of chemotherapy in patients of 150 cases of acute leukemia was investigated. Patients were divided into two groups, that is group I: 100 cases of acute leukemia treated between 1980-1984, group II: 50 cases of acute leukemia between 1985-1986. Complete remission was achieved in 66% of group I and in 82% of group II. Using multivariate analysis, the initial levels of FDP and WBC count and age were found to be important factors to induce complete remission. Female sex was suggestive of a longer remission duration and survival by discrimination analysis.

Acute Disease↗

PubMed2001

Multivariate analysis of antioxidant power and polyphenolic composition in red wines.

It has been demonstrated that the dietary intake of compounds having antioxidant activity is very important, and various chemical, biological, and electrochemical methods have been proposed to evaluate the antioxidant power of compounds such as polyphenols. Wine, although nonessential, has a high polyphenol content up to 2-3 g/L in red wines obtained by traditional maceration. The polyphenol content of wines is usually evaluated by the Folin reagent, which provides an appropriate response to the requirements of wine manufacturers. Because the presence of individual polyphenols may be evaluated by HPLC, more or less selective methods toward the various chemical classes of polyphenols have been developed. An HPLC method set up recently was applied to evaluate how individual polyphenols contributed to the overall antioxidant power (AOP) of 60 Italian red wines, trying to identify the effect that individual compounds may have on the total AOP. Application of the multivariate analysis allowed us to detect some determining compounds such as gallic acid and some flavonols. On the basis of the correlation between two traditional chemical methods, namely the total polyphenol determination by the Folin reagent and the flavanol determination by the condensation reaction with p-(dimethylamino)-cinnamaldehyde, it was shown that the use of these two merely chemical methods is well correlated (r = 0.83 and 0.87) to an AOP evaluation of red wines.

Antioxidants↗

PubMed1998

Predicting postprimary treatment services and drug use outcome: a multivariate analysis.

The substance abuse treatment field is continually challenged to develop interventions that encourage drug abusers to remain longer in therapeutic services and that facilitate improved outcomes. As one of those interventions, case management has generally not been subjected to multivariate analysis to evaluate its role in accomplishing those goals. Using a sample of 444 veterans who received substance abuse treatment services, this study examines relationships among demographic and psychosocial variables at intake, assignment to either traditional or enhanced (case management) treatment services, and both proximal (postprimary treatment contact) and distal (severity of drug use) measures of outcome. Multivariate analyses reveal that case-managed clients stay longer in postprimary treatment services than non-case-managed clients, and consequently, longer postprimary treatment contact leads to better drug use outcomes. The implications of these findings are discussed.

Adult↗

PubMed1997

Predicting survival from out-of-hospital cardiac arrest: a multivariate analysis.

From 954 attempts to resuscitate patients from out-of-hospital cardiac arrest two datasets were derived, namely 861 cases of cardiac arrest and 906 cases of either cardiac or primary respiratory arrest. For each dataset, multivariate analysis was performed by fitting a number of explanatory variables with respect to the outcomes of admission to hospital and discharge home in logistic regression models. There were numerous interactions between these variables. Being conscious at the time of the arrival of the ambulance crew and subsequently having cardiac arrest strongly predicted survival, as did both the presence of a witness to the arrest and the initiation of cardiopulmonary resuscitation (CPR) by a bystander; this latter effect was a marker for early CPR. The strongest predictor of a poor outcome was delay to CPR or delay to advanced cardiac life support.

Age Distribution↗

PubMed1997

Pancreaticojejunal anastomotic leak after pancreaticoduodenectomy--multivariate analysis of perioperative risk factors.

The records of 131 consecutive patients with periampullary carcinoma who underwent pancreaticoduodenectomy within a 12-year period were reviewed to determine the perioperative risk factors of pancreaticojejunal (PJ) anastomotic leak. Twenty-one PJ leaks were identified, for a frequency of 16% (21 of 131); 19% (4 of 21) of these patients eventually died of PJ leak-related complications. A total of 23 items of perioperative data, presumed as risk factors predisposing to PJ leak, were examined. By univariate analysis, advanced age, prolonged duration of untreated jaundice, deep jaundice, decreased creatinine clearance, increased intraoperative blood loss, and shock during operation were statistically significant. However, by multivariate analysis, only duration of jaundice, creatinine clearance, and intraoperative blood loss turned out to be independent risk factors. Noteworthily, jaundiced patients with impaired creatinine clearance not only had a higher incidence of PJ leak, but were also more liable to experience sepsis and intraabdominal bleeding, which uniformly elicited a grave clinical course. Routine preoperative biliary drainage failed to enhance the security of PJ. Completion pancreatectomy continued to carry a poor prognosis, and should be avoided when possible and replaced by early, aggressive radiologic intervention.

Adult↗

PubMedDate not supplied

Malignant pleural mesothelioma. Multivariate analysis of prognostic factors on 113 patients.

We report on clinical features of 113 cases of pathologically confirmed Malignant Pleural Mesothelioma, observed in Genoa (Italy) between 1979 and 1985. Overall median survival was 10 months. Among the pretreatment variables studied (age, sex, asbestos exposure, pathological type, chest pain and dyspnea at the time of diagnosis), the only one of prognostic value in the univariate analysis was the histological subtype: median survivals were 12, 7 and 4 months for the patients in the epithelial, mixed, and fibrosarcomatous groups, respectively (p = 0.0012). A multivariate analysis confirmed the independent predictive power of the histotype (p = 0.0022). A review of literature data concerning prognostic factors in Malignant Pleural Mesothelioma is presented.

Adult↗

PubMed2000

[Multivariate analysis of the risk of hemorrhagic recurrence in gastroduodenal ulcer. Study of a prospective series].

AIM: To construct a model to enable calculation of rebleeding risk in patients admitted to a hospital emergency department with upper gastrointestinal bleeding secondary to a gastric or duodenal ulcer. METHODS: We analyzed 317 patients admitted during a 13-month period with an episode of upper gastrointestinal bleeding secondary to a gastroduodenal ulcer. The patients were followed-up for 30 days after discharge. Uni- and multivariate analysis of the clinical and endoscopic variables was performed on variables that could be associated with an increased risk of rebleeding. RESULTS: In the univariate analysis the following variables were significantly associated with an increased risk of rebleeding: the presence of blood in the endoscopically examined tract (p < 0.0001), clean ulcer base (p < 0.0001), low blood flow (p < 0.047) and size of the ulcer > 2 cm (p < 0.004). Independent risk variables identified by multivariate logistic regression analysis were low cardiac output, the presence of blood in the endoscopically examined tract, size of the ulcer, and type of ulcer base. CONCLUSION: Patients with a clean ulcer base, smaller than 2 cm, without blood in the endoscopically examined tract and with stable hemodynamics were at very low risk of rebleeding and could be discharged directly from the emergency room.

Analysis of Variance↗

PubMed1995

Prognostic value of neural invasion in rectal carcinoma: a multivariate analysis on 339 patients with curative resection.

To determine whether neural invasion or other clinico-pathological factors are prognostic, we performed a retrospective study on 339 rectal carcinomas. The overall 5-year survival was 62%. In the multivariate analysis, age over 60 years, a distance from the anal verge of less than 6 cm, the number of positive lymph nodes, neural invasion and tumour penetration were found to be prognostic. A scoring system identified five prognostic groups of patients. Neural invasion is an independent prognostic factor in our scoring system and it is suggested that this parameter should be taken into consideration for postsurgical treatment.

Adolescent↗

PubMed2003

Improving structure-based virtual screening by multivariate analysis of scoring data.

Three different multivariate statistical methods, PLS discriminant analysis, rule-based methods, and Bayesian classification, have been applied to multidimensional scoring data from four different target proteins: estrogen receptor alpha (ERalpha), matrix metalloprotease 3 (MMP3), factor Xa (fXa), and acetylcholine esterase (AChE). The purpose was to build classifiers able to discriminate between active and inactive compounds, given a structure-based virtual screen. Seven different scoring functions were used to generate the scoring matrices. The classifiers were compared to classical consensus scoring and single scoring functions. The classifiers show a superior performance, with rule-based methods being most effective. The precision of correctly predicting an active compound is about 90% for three of the targets and about 25% for acetylcholine esterase. On the basis of these results, a new two-stage approach is suggested for structure-based virtual screening where limited activity information is available.

Acetylcholinesterase↗

PubMed1997

Prospective comparison of four lymphoblastoid interferon alpha schedules for chronic hepatitis C. A multivariate analysis of factors predictive of sustained response to treatment.

OBJECTIVE: Interferon alpha (IFN-alpha) provides effective treatment in some patients with chronic hepatitis C. Since this drug is costly and causes potentially severe side effects, there is a need for clarification of the optimal dose regimen and treatment duration and of the predictive factors of long-term response to this therapy. DESIGN: Prospective, randomized study in patients with chronic hepatitis C. SETTING: 'Crespi' Division of Medicine and Centre for Liver Diseases, Niguarda Hospital, Milan, Italy. PATIENTS AND METHODS: One hundred and forty-two patients with chronic hepatitis C were randomized to receive IFN-alpha at a dosage of 2-4 mega units/square metre of body surface area thrice weekly for 6-12 months. Eleven baseline variables that might predict sustained response to IFN-alpha were evaluated in this series. Sustained response was defined as normalization of transaminase levels observed by the fourth month of therapy and lasting for at least 6 months after treatment withdrawal. RESULTS: According to univariate analysis, variables significantly associated with sustained response to treatment were: hepatitis C virus (HCV) genotype, treatment duration, serum HCV-RNA level and duration of hepatitis. On multivariate analysis only two of these variables were found to be independently associated with sustained response to IFN-alpha: HCV genotype (P < 0.0001) and treatment duration (P = 0.0015). In the patients infected with genotype 1b, IFN-alpha was effective only when administered at the higher dosage and for the longer period. CONCLUSION: Viral genotype and treatment duration are independently related to sustained response to IFN-alpha in patients with chronic hepatitis C. The patients infected with HCV genotype 1b should receive IFN-alpha at the higher dosage and for the longer period.

Adult↗

PubMed1991

Poor prognosis for malignant melanoma in Northern Ireland: a multivariate analysis.

All cases of cutaneous malignant melanoma, CMM, diagnosed in Northern Ireland between 1974-1978 were reviewed, classified and followed up until the end of 1984. The overall 5 year survival is 54%, among the worst reported in recent literature. Multivariate analysis of these cases confirms some previous findings from other studies, but also reveals features not apparent in univariate analysis. Prognosis worsens with increasing thickness and the presence of ulceration. Likewise histopathological type has an independent effect on survival, ALM having the worst prognosis. Tumour profile emerges as a significant feature affecting prognosis, flat lesions having the poorest outlook, given their thickness. Survival is worse with increasing age. Anatomical site is less important than suggested by previous univariate analysis. Sex has little influence on prognosis when adjusted for the other variables. Cell type and pigmentation are of no prognostic value. Several features including diagnostic delay contribute to the poor overall survival for CMM in Northern Ireland. Educational intervention is essential if this trend is to be reversed.

Female↗

PubMed2001

[Prognostic factors of renal pelvic and ureteral cancer: a multivariate analysis].

We clinicopathologically reviewed 54 cases (40 males and 14 females) of renal pelvic and ureteral cancer examined between 1983 and 1998, in order to determine the impact of prognostic factors. Follow-up ranged from 2 to 173 months (mean, 45.6 months). The age of the patients ranged from 39 to 88 years (mean, 68.9 years). The 1, 3 and 5-year cause-specific survival rates (Kaplan-Meier's method) for all of the patients were 74.6%, 58.4% and 54.5%, respectively. According to univariate analysis, a high grade and high stage of tumor, the presence of lymphatic invasion and positive regional lymph nodes indicated a significantly poor prognosis. On the other hand, multivariate analysis using Cox proportional hazards regression revealed the presence of lymphatic invasion as the most significant predictor of survival. Therefore, patients with lymphatic invasion have a poor prognosis, and the development of effective adjuvant therapy is needed to improve the outcome in these patients.

Adult↗

PubMed1998

[Social health evolution in Vall d'Uixó. Application of multivariate analysis as a new health status indicator method].

OBJECTIVES: This study evaluated the relative position of Vall d'Uixó within the province of Castellón, the Valencian Community and Spain. DESIGN: The study covers the period from 1981 to 1993. A multivariate analysis of the main components was performed. This compared the interrelationship of these indicators in the different zones analysed. PATIENTS AND OTHER PARTICIPANTS: Our study focused on an area of 27,387 population, geographically within the province of Castellón in the south-west of La Plana county. RESULTS: The analysis showed that Vall d'Uixó had a low level of development and little economic activity. It had a relatively young population. CONCLUSIONS: The health problems were linked to the social and economic situation. Apart from the re-creation of industrial jobs, it would be desirable to improve programmes to monitor TB and cardiovascular diseases.

Cause of Death↗