Biomedical subjects

Matteo Bottai

Publications and source records attributed to Matteo Bottai.

10 recordsLinked to original sources

PubMed2006

Reference equations for spirometry from a general population sample in central Italy.

Aim of this study was to derive new lung function reference equations and compare the predicted values with those from three sets of existing reference equations: one derived from a Northern Italy population and the two others widely used in European (ECCS) and American (NHANES III) clinical practice. Reference equations for flow-volume curve indexes and VC were derived on 497 normal subjects, aged 8-74, from the epidemiological survey in Pisa, Central Italy (1991-1993). By applying natural cubic splines, one single smooth and continuous equation for the entire age range was provided for each index, separately by gender. Along with age and height, reference values also depended on BMI. Differences among the four reference equations for FEV(1), FVC, VC were quantified for average subjects. The magnitude largely varied over the age range in both genders, reaching up to half litre of air volume at specific ages. Age-gender-specific prevalence rates of airway obstruction, as defined by the ERS criterion, largely varied by applying the considered equations, the differences ranging from -3% to 28%. The observed discrepancies confirm that reference equations should be derived from a population most similar to that for which the equations are to be used and based on measurements obtained by the same instrument and testing procedures, in order to minimize technical variability in lung function both for clinical and epidemiological purposes.

Adolescent↗

PubMed2006

Quantile regression for longitudinal data using the asymmetric Laplace distribution.

In longitudinal studies, measurements of the same individuals are taken repeatedly through time. Often, the primary goal is to characterize the change in response over time and the factors that influence change. Factors can affect not only the location but also more generally the shape of the distribution of the response over time. To make inference about the shape of a population distribution, the widely popular mixed-effects regression, for example, would be inadequate, if the distribution is not approximately Gaussian. We propose a novel linear model for quantile regression (QR) that includes random effects in order to account for the dependence between serial observations on the same subject. The notion of QR is synonymous with robust analysis of the conditional distribution of the response variable. We present a likelihood-based approach to the estimation of the regression quantiles that uses the asymmetric Laplace density. In a simulation study, the proposed method had an advantage in terms of mean squared error of the QR estimator, when compared with the approach that considers penalized fixed effects. Following our strategy, a nearly optimal degree of shrinkage of the individual effects is automatically selected by the data and their likelihood. Also, our model appears to be a robust alternative to the mean regression with random effects when the location parameter of the conditional distribution of the response is of interest. We apply our model to a real data set which consists of self-reported amount of labor pain measurements taken on women repeatedly over time, whose distribution is characterized by skewness, and the significance of the parameters is evaluated by the likelihood ratio statistic.

Analgesics↗

PubMed2006

Surgical ventricular reverse remodeling in severe ischemic dilated cardiomyopathy: the relevance of the left ventricular equator as a prognostic factor.

OBJECTIVES: Surgical ventricular reverse remodeling has been shown to possibly improve hemodynamics and symptoms, but effects on long-term mortality are not established. No consistent data are available on which patients will benefit most from this procedure. This study was designed to analyze the predictors of long-term survival after surgical ventricular reverse remodeling in patients with ischemic cardiomyopathy. METHODS: Eighty-five patients who underwent surgical ventricular reverse remodeling between May 1991 and October 2003 were retrospectively analyzed. Left ventricular wall motion and left ventricular equatorial diameter were assessed by means of angioventriculography. Left ventricular ejection fraction and volumes were measured by means of echocardiography. Cox regression analysis was used in several combinations to create a final model for identifying predictors of death. RESULTS: Actuarial survival after 1, 3, 5, and 10 years was 89%, 79%, 75%, and 75%, respectively. New York Heart Association class improved from 2.9 +/- 1.0 to 1.3 +/- 0.5 (P < .0001), left ventricular ejection fraction increased from 27.6% +/- 6.3% to 43.0% +/- 10.1% (P < .0001), and left ventricular end-systolic volume index decreased from 89.6 +/- 27.6 mL/m2 to 56.5 +/- 34.5 mL/m2 (P < .0001). Multivariate analysis identified left ventricular equatorial diameter of 70 mm or greater (hazard ratio, 5.28; 95% confidence interval, 1.79-11.71; P = .020) and segmental akinesia (hazard ratio, 4.46; 95% confidence interval, 1.23-17.12; P = .024) as the only independent predictors of death. CONCLUSIONS: In this analysis of a single cohort of patients, surgical ventricular reverse remodeling improves the symptoms of ischemic cardiomyopathy, as well as left ventricular function, shape, and volume, with encouraging long-term outcomes, particularly in patients with dyskinesia. A left ventricular equatorial diameter of 70 mm or greater appears to be an important independent prognostic factor, which suggests the relevance of the left ventricular equatorial region for effective surgical reverse remodeling.

Adult↗

PubMed2006

Survival and restoration of pulmonary perfusion in a long-term follow-up of patients after acute pulmonary embolism.

We followed prospectively 834 consecutive patients (70% inpatients), evaluated for suspected pulmonary embolism, for a median time of 2.1 years (range, 0-4.8 yr), and compared the survival rates in patients with proven pulmonary embolism (n=320) with those without (n=514). In multivariate analysis, we modeled the probability of surviving in patients with pulmonary embolism as a function of the extent of pulmonary vascular obstruction at baseline. Among patients with pulmonary embolism, a scintigraphic follow-up was pursued to assess the restoration of pulmonary perfusion over a 1-year period. We found that massive pulmonary embolism (vascular obstruction>or=50%) is a risk factor for mortality within the first few days after onset but, subsequently, has no significant effect on survival. The adjusted risk of death in patients with massive pulmonary embolism was 8-fold higher than in patients without embolism within the first day after the incident event. By contrast, the adjusted risk of death for patients with minor or moderate pulmonary embolism (vascular obstruction<50%) was no higher than in patients without embolism at any time after onset. Most of the patients who survived a year after pulmonary embolism showed a nearly complete restoration of pulmonary perfusion with a considerable improvement in arterial oxygenation. Four (1%) of the 320 patients with pulmonary embolism at presentation developed chronic thromboembolic pulmonary hypertension. These patients featured persistent large perfusion defects in sequential lung scans. Pulmonary embolism with vascular obstruction>or=50% is a strong, independent predictor of reduced short-term survival. This underscores the need for a prompt diagnosis of the disease. Monitoring the resolution of pulmonary embolism by lung scanning may prove useful in identifying patients with persistent perfusion abnormalities who may be at risk of chronic thromboembolic pulmonary hypertension.

Adolescent↗

PubMed2006

Age and temporal trends of total physical activity among Swedish women.

PURPOSE: Few epidemiological studies have been conducted among middle-aged women on long-term total and specific physical activity (PA) trends. We studied in a cross-sectional setting the relationship of self-reported total daily PA with age and calendar time. METHODS: In a population-based cohort of 38,988 women aged 49-83 yr in central Sweden, information was collected on physical activity, such as work or occupation, household work, walking or bicycling, exercise, watching TV or reading, and other lifestyle factors through a self-administered questionnaire. Total and specific daily PA levels at ages 15, 30, and 50 yr were recalled retrospectively and measured as metabolic equivalents (MET.h.d(-1)). RESULTS: Total PA level linearly decreased with calendar time in all three age groups (slope for 5-yr change in calendar time among those 15 yr of age = -0.82; 95% confidence interval (CI), -0.86 to -0.78; among those 30 yr of age=-0.42; 95% CI, -0.45 to -0.38; and among those 50 yr of age = -0.62; 95% CI, -0.66 to -0.58). High-intensity activities such as walking or bicycling decreased by 0.21 MET.h.d(-1) (95% CI, -0.22 to -0.20) every 5-calendar-year change among adolescents between the 1930s and 1960s. Total activity level decreased in all age groups by an average of approximately 3MET.h(-1).d(-1), corresponding to approximately 45 min of brisk walking. CONCLUSIONS: Our results suggest that intervention efforts aimed at engaging in healthful amounts of physical activity are needed throughout the life cycle.

Adult↗

PubMed2005

Comparison of 3 clinical models for predicting the probability of pulmonary embolism.

Two clinical models have been described to predict the probability of pulmonary embolism: the Canadian (or Wells) model, and the Geneva model. A third model has been developed recently at our institution (the Pisa model). We compared the performance of the 3 models in 215 consecutive patients with suspected pulmonary embolism. The clinical probability predicted by the models was categorized as low, intermediate, or high. In all patients, pulmonary angiography was used as the reference diagnostic standard. In patients with pulmonary embolism, the extent of pulmonary embolization was assessed on the lung scan as an index of disease severity. The prevalence of pulmonary embolism was 43.3%, and the median extent of pulmonary embolization at diagnosis was 39.8% (range, 4.5%-75.3%). The proportions of patients categorized as having low, intermediate, or high probability were, respectively: 12%, 60%, and 28%, for the Geneva model; 30%, 55%, and 15%, for the Wells model; 37%, 37%, and 26% for the Pisa model. The frequencies of pulmonary embolism in the low, intermediate, and high probability categories were, respectively: 50%, 39%, and 49% for the Geneva model; 12%, 54%, and 64% for the Wells model; 5%, 42%, and 98% for the Pisa model. Among patients with pulmonary embolism, there was a strong, positive relation between clinical probability predicted by the Pisa model and the extent of pulmonary embolization. The Pisa model proved more accurate than the 2 other models. It may be useful to physicians in defining precisely the pretest probability of pulmonary embolism.

Adolescent↗

PubMed2004

Predictors of response in a sample of treatment-resistant psychotic patients on clozapine.

This study aims at identifying potential predictors of clinical response and functional outcome in 101 neuroleptic-refractory patients with a DSM-III-R diagnosis of schizophrenia (N = 34), schizoaffective disorder (N = 30) or bipolar disorder with psychotic features (N = 37), naturalistically treated with clozapine over a 48-month period. The "clinical response" and "functional outcome" criteria were respectively defined a priori as: a reduction of at least 50 % in the Brief Psychiatric Rating Scale total score in one evaluation with respect to baseline; and a Global Assessment of Functioning Scale score of at least 50. Several clinical and socio-demographic variables were assessed at baseline and only the diagnosis of bipolar disorder was significantly related with the clinical response. Variables significantly related with the functional outcome were female gender, university education and early age at onset.

Age of Onset↗

PubMed2004

Role of the chest radiograph in the preoperative assessment of the pulmonary function in patients with cirrhosis candidates to liver transplant.

PURPOSE: To appraise the role of chest radiography (CXR) in the clinical assessment of pulmonary complications occurring as a result of liver disease of any cause, a standardised reading of CXR was compared both with the results of lung function studies and with the severity of liver disease in 60 consecutive patients with cirrhosis candidates to liver transplant. MATERIALS AND METHODS: CXR were scored for signs of cardiomegaly, enlargement of central and or peripheral vessels, hyperkinetic circulatory and/or intravascular volume states, abnormally increased interstitial lung markings, and pleural effusion by three independent observers. RESULTS: The CXR score of this complete vascular-interstitial deficiency showed a high interobserver reproducibility and was significantly increased in those patients with a more decompensated liver cirrhosis. Moreover, a larger number of CXR signs of vascular and interstitial deficiency was present in those patients who had a more severe cirrhosis (Child-Pugh class 3). Functional indices of pulmonary gas exchange and diffusing capacity were worse in patients with end-stage liver cirrhosis, and for some indices the correlation was statistically significant. The comparison between lung function and CXR score showed that on average lung function impairment was significantly less severe in patients with lower CXR scores. CONCLUSIONS: In conclusion, the information derived from a standardised reading of CXR is valuable in the clinical assessment of the pulmonary damage induced by liver cirrhosis as it allows discrimination of classes of severity of liver disease and of lung function impairment. When integrated with physiologic measurements and, if necessary, with high resolution tomographic studies, chest radiography helps to discriminate patients with advanced liver cirrhosis and progressing towards a hepatopulmonary syndrome, who need a proper therapeutic management.

Adult↗

PubMed2003

A structured clinical model for predicting the probability of pulmonary embolism.

PURPOSE: To develop a structured model to predict the clinical probability of pulmonary embolism. METHODS: We studied 1,100 consecutive patients with suspected pulmonary embolism in whom a definite diagnosis had been established. We used logistic regression analysis to estimate the probability of pulmonary embolism based on patients' clinical characteristics; the probability was categorized as low (< or = 10%), intermediate (>10%, < or = 50%), moderately high (>50%, < or = 90%), or high (>90%). RESULTS: The overall prevalence of pulmonary embolism was 40% (n = 440). Ten characteristics were associated with an increased risk of pulmonary embolism (male sex, older age, history of thrombophlebitis, sudden-onset dyspnea, chest pain, hemoptysis, electrocardiographic signs of acute right ventricular overload, radiographic signs of oligemia, amputation of the hilar artery, and pulmonary consolidation suggestive of infarction), and five were associated with a decreased risk (prior cardiovascular or pulmonary disease, high fever, pulmonary consolidation other than infarction, and pulmonary edema on the chest radiograph). With this model, 432 patients (39%) were rated a low probability, of whom 19 (4%) had pulmonary embolism; 283 (26%) were rated an intermediate probability, of whom 62 (22%) had pulmonary embolism; 72 (7%) were rated a moderately high probability, of whom 53 (74%) had pulmonary embolism; and 313 (28%) were rated a high probability, of whom 306 (98%) had pulmonary embolism. CONCLUSION: This prediction model may be useful for estimating the probability of pulmonary embolism before obtaining definitive test results.

Adolescent↗

PubMed2003

Clozapine in treatment-resistant patients with schizophrenia, schizoaffective disorder, or psychotic bipolar disorder: a naturalistic 48-month follow-up study.

BACKGROUND: The aim of this study was to evaluate the long-term efficacy and safety of clozapine in patients with treatment-resistant schizophrenia, schizoaffective disorder, or bipolar disorder with psychotic features. METHOD: 101 patients with a DSM-III-R diagnosis of schizophrenia (N = 34); schizoaffective disorder, bipolar type (N = 30); or bipolar disorder with psychotic features (N = 37) were naturalistically treated with clozapine at flexible doses over a 48-month period. Data were collected from 1994 to 2000. The Brief Psychiatric Rating Scale (BPRS) and Clinical Global Impressions-Severity of Illness scale total predicted scores over time were estimated with random-effects regression models. Time to response to clozapine, defined as 50% reduction of BPRS score, was analyzed in the 3 diagnostic groups using the Kaplan-Meier method. Survival curves were compared using the log-rank test. RESULTS: The BPRS total predicted score halved its baseline value in 3 months for bipolar disorder patients, in 6 months for schizoaffective disorder patients, and in 24 months for schizophrenia patients. The proportion of subjects who satisfied the criterion for response to clozapine after 48 months of follow-up was significantly (p <.01) higher in the schizoaffective and bipolar disorder groups (90.0% and 83.8%, respectively) than in the schizophrenia group (64.7%). Baseline scores on the Global Assessment of Functioning (GAF) showed low levels of psychosocial and occupational functioning in all 3 groups. After 48 months of treatment, GAF scores showed a functional improvement in all 3 groups, with significantly (p <.01) greater improvement in the bipolar disorder group compared with the other groups. CONCLUSION: The findings of this study confirm the efficacy and safety of clozapine for treatment-resistant patients with a diagnosis of schizophrenia, schizoaffective disorder, or bipolar disorder with psychotic features. Patients with schizoaffective disorder and those with bipolar disorder show greater clinical improvement than those with schizophrenia. Patients with bipolar disorder have the shortest time to response and the highest psychosocial and occupational functioning levels. Patients with schizoaffective disorder have the lowest treatment discontinuation rate.

Adult↗