Biomedical subjects

A Ciampi

Publications and source records attributed to A Ciampi.

At least 19 recordsLinked to original sources

PubMed2005

Dietary patterns and lifestyle factors in the Norwegian EPIC cohort: the Norwegian Women and Cancer (NOWAC) study.

OBJECTIVE: To identify different dietary patterns in Norway using a combination of cluster and factor analysis. DESIGN: Cross-sectional study. SETTING: Nation-wide, population-based study. SUBJECTS: The Norwegian EPIC cohort is a subcohort of the Norwegian Women and Cancer study (NOWAC), and consist 37.226 women aged 41-56 y who answered a food frequency questionnaire (FFQ) in 1998. INTERVENTIONS: The associations among 50 food variables were first investigated by using principal component analysis. Five important factors were found. The five principal components were then used as input in the cluster analysis. Different socioeconomic and lifestyle variables were examined. RESULTS: Six clusters of dietary patterns were found, and were labelled accordingly: 'traditional fish eaters', 'healthy eaters', 'average, less fish, less healthy', 'Western', 'traditional bread eaters', and 'alcohol users'. The traditional fish eaters and the traditional bread eaters were both highly represented in the north and west of Norway and were more likely to be present among persons with lower income and lower education. The healthy and the alcohol drinkers were found mostly in the south and east and were more likely to have higher income. Persons in the alcohol group were more likely to be current smokers. The western group had the highest percentage of three or more persons in the household and the shortest time since last birth, indicating that families with children dominate this group. CONCLUSION: Our data indicate six different dietary patterns in Norway, each with different socio-demographic and lifestyle characteristics. SPONSORSHIP: The Norwegian Cancer Society (E 04038/006).

Adult↗

PubMed2002

Evaluation of under- and overreporting of energy intake in the 24-hour diet recalls in the European Prospective Investigation into Cancer and Nutrition (EPIC).

OBJECTIVE: To evaluate under- and overreporting and their determinants in the EPIC 24-hour diet recall (24-HDR) measurements collected in the European Prospective Investigation into Cancer and Nutrition (EPIC). DESIGN: Cross-sectional analysis. 24-HDR measurements were obtained by means of a standardised computerised interview program (EPIC-SOFT). The ratio of reported energy intake (EI) to estimated basal metabolic rate (BMR) was used to ascertain the magnitude, impact and determinants of misreporting. Goldberg's cut-off points were used to identify participants with physiologically extreme low or high energy intake. At the aggregate level the value of 1.55 for physical activity level (PAL) was chosen as reference. At the individual level we used multivariate statistical techniques to identify factors that could explain EI/BMR variability. Analyses were performed by adjusting for weight, height, age at recall, special diet, smoking status, day of recall (weekday vs. weekend day) and physical activity. SETTING: Twenty-seven redefined centres in the 10 countries participating in the EPIC project. SUBJECTS: In total, 35 955 men and women, aged 35-74 years, participating in the nested EPIC calibration sub-studies. RESULTS: While overreporting has only a minor impact, the percentage of subjects identified as extreme underreporters was 13.8% and 10.3% in women and men, respectively. Mean EI/BMR values in men and women were 1.44 and 1.36 including all subjects, and 1.50 and 1.44 after exclusion of misreporters. After exclusion of misreporters, adjusted EI/BMR means were consistently less than 10% different from the expected value of 1.55 for PAL (except for women in Greece and in the UK), with overall differences equal to 4.0% and 7.4% for men and women, respectively. We modelled the probability of being an underreporter in association with several individual characteristics. After adjustment for age, height, special diet, smoking status, day of recall and physical activity at work, logistic regression analyses resulted in an odds ratio (OR) of being an underreporter for the highest vs. the lowest quartile of body mass index (BMI) of 3.52 (95% confidence interval (CI) 2.91-4.26) in men and 4.80 (95% CI 4.11-5.61) in women, indicating that overweight subjects are significantly more likely to underestimate energy intake than subjects in the bottom BMI category. Older people were less likely to underestimate energy intake: ORs were 0.58 (95% CI 0.45-0.77) and 0.74 (95% CI 0.63-0.88) for age (> or =65 years vs. <50 years). Special diet and day of the week showed strong effects. CONCLUSION: EI tends to be underestimated in the vast majority of the EPIC centres, although to varying degrees; at the aggregate level most centres were below the expected reference value of 1.55. Underreporting seems to be more prevalent among women than men in the EPIC calibration sample. The hypothesis that BMI (or weight) and age are causally related to underreporting seems to be confirmed in the present work. This introduces further complexity in the within-group (centre or country) and between-group calibration of dietary questionnaire measurements to deattenuate the diet-disease relationship.

Adult↗

PubMed2001

Tolerability of antihypertensive drugs in a community-based setting.

BACKGROUND: Outside the experimental environment of clinical trials, the tolerability of angiotensin-converting enzyme inhibitors (ACEIs), calcium channel blockers (CCBs), and the angiotensin II antagonist losartan has not been compared. OBJECTIVES: The purpose of this study was to estimate, in current clinical practice, the 3-month cumulative incidence of side effects among first-time users of losartan, ACEIs, and CCBs for hypertension. METHODS: We conducted a prospective cohort study through a network of 173 pharmacies across Canada to identify patients with hypertension who were newly prescribed monotherapy with losartan, an ACEI, or a CCB. Individuals were interviewed by telephone 3 times over a 3-month period to determine perceived side effects of the antihypertensive medication prescribed. Data were analyzed using a multivariate logistic regression model. RESULTS: Among the 663 eligible individuals, the 3-month cumulative incidence of perceived side effects was 52.5% (42/80), 60.2% (222/369), and 69.6% (149/214) for those treated with losartan, an ACEI, and a CCB, respectively. After adjustment for sex, age, level of education, number of symptoms perceived the week before entering the study, prior use of antihypertensive drugs, current use of any other drug, drug insurance coverage, and duration of hypertension, the odds of reporting a side effect were significantly higher among patients treated with an ACEI (odds ratio [OR] = 1.78: 95% CI, 1.02-3.12) or a CCB (OR = 2.65; 95% CI, 1.47-4.78) compared with patients treated with losartan. CONCLUSIONS: In a community-based setting, we observed that losartan is better tolerated than ACEIs and CCBs. Given that the occurrence of side effects may contribute to lower adherence to drug treatment, the low incidence of side effects associated with losartan makes it an attractive antihypertensive drug choice.

Adolescent↗

PubMed2001

Family history and the risk of coronary heart disease: comparing predictive models.

Family history is commonly used when evaluating coronary heart disease (CHD) risk yet it is usually treated as a simple binary variable according to the occurrence or non-occurrence of disease. This definition however fails to consider the potential components of a family history which may in fact exert different degrees of influence on the overall risk profile. The purpose of this paper is to compare different predictive models for CHD which incorporate family history as either a binary variable or different types of family risk indices in terms of their predictive ability. Models for estimating CHD risk were constructed based on usual risk factors and different family history variables. This construction was accomplished using logistic regression and RECursive Partition and AMalgamation (RECPAM) trees. Our analyses demonstrate the importance of using more sophisticated definitions of family history variables compared to a simple binary approach since this leads to a significant improvement in the predictive ability of CHD risk models.

Adult↗

PubMed2001

A method to assess predominant energies of exposure in a nuclear research centre--Saclay (France).

A study of dosimetric errors is under way within an international collaborative study of cancer risk among workers in the nuclear industry. The objective is to quantify errors in the estimated photon doses to individual organs used for cancer risk estimation. One source of errors is the response of old dosemeters in workplace exposure conditions. As these conditions are not well known, the International Study must rely on expert estimations. This paper describes a method to assess the proportion of the dose from photons in three energy ranges (< 100, 100-300, > or = 300 keV) using the responses under filters of a multi-element dosemeter. The method was tested on experimental and simulated data and provides a good estimate of the proportion of dose from photons below 100 keV, the most critical for dosemeter response. It was applied to personnel readings in one facility, confirming the experts' estimation. Beyond the International Study, the method has implication for the monitoring and protection of workers.

Female↗

PubMed2001

Reliability and validity of commercially available, direct radioimmunoassays for measurement of blood androgens and estrogens in postmenopausal women.

In large-scale epidemiological studies on endogenous sex steroids and cancer risk, direct immunoassays of circulating hormone levels have the advantage of being fast and comparatively inexpensive while requiring only small sample volumes. On the other hand, indirect assays after organic extraction and chromatographic prepurification have the advantage of reducing specific interferences and matrix effects and hence are thought to have better validity. We compared direct assays of testosterone (T, six different assays), Delta4-androstenedione (A, four assays), estrone (E(1), one assay), and 17beta-estradiol (E(2), five assays) with measurements obtained by an indirect assay in a representative subset of 20 postmenopausal women who were part of a large prospective cohort study. Within-batch reproducibilities of the subject rankings by relative hormone levels were good (intraclass correlations >0.89) for all direct assays tested. Between batches, reproducibilities generally were also acceptable (r > 0.80) to good (r > 0.90) in terms of Pearson's correlations. The between-batch reproducibility in terms of intraclass correlations was systematically lower in terms of Pearson's correlations, however, because of between-batch variations in the absolute scale of measurements. The relative validity of direct versus indirect assays in terms of the subjects' ranking by relative hormone levels was also high for most of the kits tested for T, A, and E(1) (Pearson's correlations between 0.70 and 0.89) but was high for only two kits of five tested for E(2) (correlations of 0.86 and 0.84). On an absolute scale, mean measurement values were generally higher for direct assays than for the indirect assay and, for each hormone, varied substantially, depending on the kit used. Overall, the results of this study show that, with careful selection, commercial kits for direct radioimmunoassays of steroid hormones in postmenopausal serum can be found that may allow a reliable estimation of relative risks in epidemiological studies. However, standardization of the absolute scale of assays remains problematic.

Aged↗

PubMed2001

Making decisions about cancer screening when the guidelines are unclear or conflicting.

OBJECTIVE: Our purpose was to determine the factors involved in the cancer screening decisions of family physicians in situations where the clinical practice guidelines are unclear or conflicting as opposed to when they are clear and uncontroversial. STUDY DESIGN: We analyzed discussions with focus groups using a constant comparative approach. POPULATION: A total of 73 family physicians in active practice participated in 10 focus groups (1 urban group and 1 rural group in each of 5 Canadian provinces). OUTCOME MEASURES: Our main outcome measures were participants' perceptions regarding cancer screening when the guidelines were unclear or conflicting. RESULTS: We propose a model of the determinants of cancer screening decision making with regard to unclear and conflicting guidelines. This model is rooted in the physician-patient relationship, and is an interactive process influenced by patient factors (anxiety, expectations, and family history) and physician factors (perception of guidelines, clinical practice experience, influence of colleagues, distinction between the screening styles of specialists and family physicians, and the amount of time and financial costs involved in performing the maneuver). CONCLUSIONS: Our model is unique, because it is embedded in the physician-patient relationship. Ultimately, a modified model could be used to design interventions to assist with the implementation of preventive services guidelines.

Adult↗

PubMed1999

Very early assessment of risk for in-hospital death among 11,483 patients with acute myocardial infarction. GISSI investigators.

BACKGROUND: The efficacy of reperfusion therapy after acute myocardial infarction is time dependent. The risk profile of every patient should be available as soon as possible. Our aim was to determine whether collection of simple clinical markers at hospital admission might allow reliable risk stratification for in-hospital mortality. METHODS: The subjects were 11,483 patients with acute myocardial infarction from the GISSI-2 cohort. The GISSI-1 and GISSI-3 populations were selected to validate the classification. To stratify patients, the tree-growing method called recursive partitioning and amalgamation (RECPAM) was used. This method is used to identify homogeneous and distinct subgroups with respect to outcome. RESULTS: The RECPAM algorithm provided 6 classes. RECPAM class I included Killip class 3 to class 4 patients (516 deaths/1000). RECPAM class II included Killip 2 patients older than 66 years and with anterior infarction or sites of infarction that could not be evaluated (314 deaths/1000). Killip 1 patients older than 75 years and with anterior or multiple sites or sites that could not be evaluated were included in RECPAM class III with Killip class 2 patients younger than 66 years and with systolic blood pressure less than 120 mm Hg or older than 66 years and with any other infarction site (207 deaths/1000). The other classes showed lower mortality rates (91, 32, and 12 deaths/1000 for RECPAM classes IV, V, and VI). In the GISSI 1 and GISSI 3 samples the 6 classes ranked in the same order in terms of mortality rate. With respect to low-risk strata, patients belonging to RECPAM class VI without serious clinical events in the first 4 days had a very low incidence of in-hospital death (0.9%) or morbidity. Cumulative 6-month mortality for the 6 RECPAM classes was 59.6%, 41.2%, 26.4%, 12.9%, 4. 8%, and 2.2%. CONCLUSIONS: Four simple clinical markers readily available at admission of patients with myocardial infarction allow a quick, reliable, and inexpensive prediction of risk for in-hospital and 6-month mortality. The RECPAM classification also helped identify a large subgroup of patients fit for early hospital discharge.

Aged↗

PubMed1998

Two-year time course and significance of neurohumoral activation in the Survival and Ventricular Enlargement (SAVE) Study.

AIMS: To describe the temporal evolution of neurohumoral activation in survivors of myocardial infarction with left ventricular dysfunction who are initially asymptomatic and to relate this to prognosis. METHODS AND RESULTS: Patients in the neurohumoral substudy (n = 534) of the Survival and Ventricular Enlargement (SAVE) study had their neurohormones measured at baseline, 3, 12 and 24 months post-infarction, were followed 38 +/- 7 months and had these values related to prognosis. All patients had a left ventricular ejection fraction < or = 40% early post-infarction. Atrial natriuretic peptide, aldosterone, norepinephrine and plasma renin activity decreased progressively over time. Patients with events had a persistent increase in these neurohormones with those dying within the first 24 months of follow-up having the greatest increase. Treatment with captopril affected only plasma renin activity (increase) and aldosterone (decrease). For patients who remained asymptomatic for the first 3 months post-infarction (n = 471), by multivariate analyses (all neurohormones together with non-neurohumoral risk factors), 3-month plasma atrial natriuretic peptide and aldosterone were the most closely related to the development of severe heart failure or to the combined end-points (cardiovascular death, myocardial infarction, or severe heart failure). No neurohormone was related to recurrent myocardial infarction or to cardiovascular mortality. When the last neurohormone measured prior to an event was considered along with non-neurohumoral risk factors (adjusted univariate), atrial natriuretic peptide, aldosterone, norepinephrine and epinephrine were associated with prognosis indicating that a time-dependent analysis identified a closer relationship between neurohormones and events than that identified by 3-month values. However, by multivariate analyses atrial natriuretic peptide was the only neurohormone associated with an event, being associated with the development of severe heart failure (P < 0.001) and the combined end-points (P = 0.022). However, when neurohormones were considered as binary variables, activated or non-activated (defined as > 1.96 SD above the mean of age-matched controls), an association between activation of norepinephrine prior to recurrent myocardial infarction (P < 0.001) and combined end-points (P < 0.01) and between activation of aldosterone and severe heart failure (P < 0.05) was identified. CONCLUSIONS: Neurohumoral activation decreases progressively post-infarction, but only in patients with a good prognosis. In patients with a left ventricular ejection fraction < or = 40% and asymptomatic post-infarction plasma atrial natriuretic peptide at 3 months, aldosterone levels appeared to be the neurohormones most closely associated with prognosis. Increased levels of atrial natriuretic peptide, aldosterone and norepinephrine appear to be temporally most closely associated with events.

Aldosterone↗

PubMed1998

Stratifying patients at risk of diabetic complications: an integrated look at clinical, socioeconomic, and care-related factors. SID-AMD Italian Study Group for the Implementation of the St. Vincent Declaration.

OBJECTIVE: The aim of this study was to identify subgroups of patients for whom the interactions among clinical, socioeconomic, and care-related factors determine a substantial increase in the risk of developing long-term diabetic complications. RESEARCH DESIGN AND METHODS: We performed a case-control study aimed at identifying and quantifying the risk factors for the development of major diabetic complications (eye, renal, and lower limb complications) in type 1 and type 2 diabetic patients. A total of 886 patients with renal, eye, or lower limb complications and 1,888 control subjects were enrolled in 35 diabetes outpatient clinics and 49 general practitioners' offices in 17 out of the 20 Italian regions. The main results were obtained using recursive partitioning and amalgamation (RECPAM), a technique that attempts to integrate the advantages of main effect logistic regression and tree-growing. RESULTS: The application of RECPAM led to the detection of important interactions involving clinical, socioeconomic, and care-related characteristics and allowed the identification of internally homogeneous subgroups characterized by a marked difference in the risk of developing major complications. In type 1 diabetic patients, the interaction between hypertension and smoking habits led to a dramatic increase in the complication risk, while in type 2 diabetic subjects, a poor compliance with visit scheduling was the most important predictor of complications. Furthermore, a marked difference in the risk profile was associated with patient characteristics (age, years of education, occupation). CONCLUSIONS: In the definition of the risk profile for each individual patient, socioeconomic status and level of education need to be taken under serious consideration, since they can determine a complication risk not dissimilar from hard clinical variables, such as hypertension and diabetes duration. Specific educational interventions, targeted to the socially disadvantaged strata of the population, need to be designed and implemented.

Adult↗

PubMed1998

Are drivers with CVD more at risk for motor vehicle crashes? Study of men aged 45 to 70.

OBJECTIVE: To examine whether male drivers aged 45 to 70 years suffering from cardiovascular disease (CVD) are more likely to be involved in motor vehicle crashes (MVC) that are reported to the police. DESIGN: Population-based case-control study. SETTING: Data on drivers' ages and medical conditions were compiled from the Societé de l'assurance automobile du Québec's (SAAQ) computerized files. A questionnaire was mailed to all subjects to collect additional information on annual distances driven and various driving behaviours. PARTICIPANTS: Age-stratified population-based random sample. Subjects were 2504 drivers involved in MVCs during a 6-month period; controls were 2520 drivers not involved in crashes. MAIN OUTCOME MEASURES: Proportion of drivers with CVD involved in MVCs. RESULTS: Response rate to the questionnaire was 35.5%. Analysis of the SAAQ files' entire sample of 5024 drivers showed that drivers suffering from CVD were less likely to be involved in MVCs (odds ratio [OR] 0.82, 95% confidence interval [CI] 0.67 to 0.99) than drivers without CVD. Although the estimate of risk remains unchanged when adjusted for age, it becomes statistically insignificant. It also remains unchanged and statistically insignificant when adjusted for yearly distance driven and driver behaviour, as shown by responses to the questionnaire. Drivers suffering from CVD drove significantly less each year (8900 km) than drivers without medical conditions (13,000 km). CONCLUSION: This study shows no increased risk of motor vehicle crashes for drivers suffering from CVD.

Accidents, Traffic↗

PubMed1997

Pilot study and protocol of the Canadian Trial of Atrial Fibrillation (CTAF).

Antiarrhythmic drug prophylaxis in patients with atrial fibrillation (AF) is associated with a high incidence of arrhythmic recurrence. Uncontrolled studies have suggested that low-dose amiodarone may be superior in terms of efficacy to other antiarrhythmic drugs while having an acceptable side effect profile. The Canadian Trial of Atrial Fibrillation (CTAF) is a 25-center study sponsored by the Medical Research Council of Canada to determine the best treatment strategy to maintain sinus rhythm in patients with persistent or paroxysmal AF. Recruitment began in November 1996 and will continue for 1.5 years. Patients are randomized to receive either low-dose amiodarone or conventional antiarrhythmic drug therapy. Patients assigned to the amiodarone group will receive an oral loading regimen of 10 mg/kg/day during a minimum 14-day period. Patients assigned to conventional antiarrhythmic therapy will receive 1 of 2 agents commonly used in AF prophylaxis: sotalol or propafenone. Drug selection and loading, and electrical cardioversion, if necessary, will be performed within 21 days of randomization. The long-term maintenance dose of amiodarone is 200 mg/day. We have planned a minimum follow-up period of 1 year. The primary end point is the time to the first relapse of AF. Data will be analyzed on an intention-to-treat basis. Secondary outcomes are medication toxicity, mortality, major clinical events, costs of each approach, and quality of life. For the purpose of sample size calculations, it is anticipated that recurrence of AF at 1 year will occur in 50% of patients on conventional treatment compared with 35% in those receiving amiodarone. In order to have an 80% power and a 2-tailed type I error of 0.05, assuming a 15% loss to follow-up rate, a total sample size of 400 patients will be required. A pilot study done at the Montreal Heart Institute has shown that the research protocol is feasible.

Amiodarone↗

PubMed1997

Additive beneficial effects of beta-blockers to angiotensin-converting enzyme inhibitors in the Survival and Ventricular Enlargement (SAVE) Study. SAVE Investigators.

OBJECTIVES: This study assessed whether treatment with a beta-adrenergic blocking agent in addition to the use of the angiotensin-converting enzyme (ACE) inhibitor captopril decreases cardiovascular mortality and morbidity in patients with asymptomatic left ventricular dysfunction after myocardial infarction (MI) and whether the presence of neurohumoral activation at the time of hospital discharge predicts the effects of beta-blocker treatment in these patients. BACKGROUND: Both beta-blockers and ACE inhibitors have been shown to have beneficial effects in patients with left ventricular dysfunction but no overt heart failure after MI. These patients often have persistent neurohumoral activation at the time of hospital discharge, and one would expect that patients with activation of the sympathetic nervous system derive the most benefit from treatment with beta-blockers. However, beta-blockers are underutilized in this high risk group of patients, and it is unknown whether their beneficial effects are additive to those of ACE inhibitors. METHODS: We performed a retrospective analysis of data from the Survival and Ventricular Enlargement (SAVE) study and its neurohumoral substudy. The relations between beta-blocker use at the time of randomization and neurohumoral activation and the subsequent development of cardiovascular events were analyzed by use of Cox proportional hazards models controlling for covariates. RESULTS: After adjustment for baseline imbalances, beta-blocker use was associated with a significant reduction in risk of cardiovascular death (30%, 95% confidence interval [CI] 12% to 44%) and development of heart failure (21%, 95% CI 3% to 36%), but the reduction in recurrent MI (11%, 95% CI 13% to 31%) was not significant. These reductions were independent of the use of captopril. Beta-blockers were not found to have a greater effect in patients with neurohumoral activation at the time of hospital discharge. CONCLUSIONS: The beneficial effects of beta-blocker use at the time of hospital discharge in patients with asymptomatic left ventricular dysfunction after MI appear to be additive to those of captopril and other interventions known to improve prognosis. Neurohumoral activation at the time of hospital discharge fails to identify those patients who will derive the greatest benefit from treatment with beta-blockers.

Adrenergic beta-Antagonists↗

PubMed1997

Role of interactions between psychological and clinical factors in determining 6-month mortality among patients with acute myocardial infarction. Application of recursive partitioning techniques to the GISSI-2 database. Gruppo Italiano per lo Studio della Sopravvivenza nell' Infarto Miocardico.

BACKGROUND: Clinical and epidemiological studies support the hypothesis that ischaemic cardiovascular diseases are consistently associated with psychological, social and behavioural factors. Nevertheless, the joint effect of clinical characteristics and psychological variables in determining the prognosis of acute myocardial infarction survivors has been seldom investigated. METHODS AND RESULTS: In the framework of the GISSI-2 trial, the impact of psychological factors on 6-month mortality and their interaction with clinical features was included as an ad hoc research project. Overall, 2449 patients were evaluated, 63 of whom died during the study period. All patients undertook a self-administered questionnaire (Cognitive Behavioural Assessment Hospital Form), investigating 16 psychological dimensions relative to three areas (state variables, vital exhaustion, trait variables). The impact of psychological variables on prognosis and their interaction with clinical variables were investigated by using a tree-growing technique (RECursive Partitioning and AMalgamation-RECPAM) applied to survival analysis. This statistical method allowed the identification of three separate classes, characterized by different prognoses: Class I (presence of vital exhaustion), Class II (concomitance of no vital exhaustion, depression and low levels of anxiety) and Class III (all other patients). After adjusting for the clinical variables, Class I was associated with an intermediate prognosis (hazard ratio [HR] = 2.2; 95% confidence intervals [CI], 1.2-4.0) and Class II to the worst (HR = 3.2; 95% CI = 1.6-6.2), as compared to Class III. High levels of neuroticism and extroversion were associated with a better prognosis. When clinical and psychological variables were simultaneously investigated by RECPAM, Type A behaviour was shown to be an important risk predictor among patients with better clinical conditions, i.e. those eligible for exercise test (HR = 2.6, 95% CI = 1.2-5.5). Finally, a striking difference in the impact of the most predictive clinical variables (exercise test ineligibility, late and early ventricular failure) was found among patients with and without vital exhaustion. CONCLUSIONS: This study shows that acute myocardial infarction survivors are heterogeneous with respect to 6-month mortality according to their psychological profile. More important, the impact of these variables appears comparable to that of very well known clinical risk predictors. The availability of a large study population, together with the use of innovative statistical techniques, allowed us to identify subgroups of patients for whom the joint action of clinical and psychological characteristics has been clearly documented. This suggests the need for incorporating psychological evaluation in the care of acute myocardial infarction patients.

Cohort Studies↗

PubMed1995

Tree-structured prediction for censored survival data and the Cox model.

Prediction trees for the analysis of survival data are discussed. It is shown that trees are useful not only in summarizing the prognostic information contained in a set of covariates (prognostic classification), but also in detecting and displaying treatment-covariates interactions (subgroup analysis). The RECPAM approach to tree-growing is outlined; prognostic classification and subgroup analysis are then formulated within the RECPAM framework and on the basis of the Cox proportional hazards models with a priori strata. Two examples of data analysis are presented. The issue of cross-validation is discussed in relation to computationally cheaper model selection criteria.

Algorithms↗

PubMed1994

Evidence for different clinical subtypes of type 1 diabetes mellitus: a prospective study.

The purpose of this study was to determine whether the sex, age, severity of clinical presentation, presence of ICAs, IAs, and HLA-DR and DQ types could predict, in a cohort of newly-diagnosed diabetic children: (1) the duration of beta-cell function as measured by C-peptide response to a Sustacal meal; and (2) determine if those predictors could identify disease subtypes. A cohort of 170 consecutive patients was followed for 60 months after diagnosis. We found that age (0.0029), sex (0.0136), ICA (0.0001), presence of DKA (0.0070) and C-peptide peak at diagnosis (0.0000) significantly predicted the duration of residual beta-cell function over time. Furthermore, C-peptide secretion at diagnosis, presence of ICA, age and sex allowed the identification of three different prognostic groups with varying acceleration of beta-cell loss.

Adolescent↗

PubMed1994

Parents' versus physicians' values for clinical outcomes in young febrile children.

OBJECTIVE: To compare how parents and physicians value potential clinical outcomes in young children who have a fever but no focus of bacterial infection. METHODS: Cross-sectional study of 100 parents of well children aged 3 to 24 months, 61 parents of febrile children aged 3 to 24 months, and 56 attending staff physicians working in a children's hospital emergency department. A pretested visual analog scale was used to assess values on a 0-to-1 scale (where 0 is the value of the worst possible outcome, and 1 is the value for the best) for 22 scenarios, grouped in three categories according to severity. Based on the three or four common attributes comprising the scenarios in a given group, each respondent's value function was estimated statistically based on multiattribute utility theory. RESULTS: For outcomes in group 1 (rapidly resolving viral infection with one or more diagnostic tests), no significant group differences were observed. For outcomes in groups 2 (acute infections without long-term sequelae) and 3 (long-term sequelae of urinary tract infection or bacterial meningitis), parents of well children and parents of febrile children had values that were similar to each other but significantly lower than physicians' values for pneumonia with delayed diagnosis, false-positive diagnosis of urinary tract infection, viral meningitis, and unilateral hearing loss. For bacterial meningitis with or without delay, however, the reverse pattern was observed; physicians' values were lower than parents'. In arriving at their judgment for group 2 and 3 scenarios, parents gave significantly greater weight to attributes involving the pain and discomfort of diagnostic tests and to diagnostic error, whereas physicians gave significantly greater weight to attributes involving both short- and long-term morbidity and long-term worry and inconvenience. Parents were significantly more likely to be risk-seeking in the way they weighted the attributes comprising group 2 and 3 scenarios than physicians, ie, they were more willing to risk rare but severe morbidity to avoid the short-term adverse effects of testing. CONCLUSIONS: Parents and physicians show fundamental value differences concerning diagnostic testing, diagnostic error, and short- and long-term morbidity; these differences have important implications for diagnostic decision making in the young febrile child.

Attitude of Health Personnel↗

PubMed1993

Different rates of conversion to IDDM in siblings of type 1 diabetic children: the Montreal family study.

This study was undertaken to analyze the risk of developing insulin-dependent diabetes (IDDM) in siblings of type 1 diabetic children. Islet-cell antibodies (ICA) were tested in 568 subjects, siblings of type 1 diabetic children. The subjects were followed prospectively for the conversion to clinical diagnosis of IDDM. As a result siblings who were islet cell antibody (ICA)+ positive at the time of diagnosis of the diabetic sibling (index case) had a significantly higher risk of developing IDDM than those who were ICA-. However, of the 19 siblings who developed IDDM, only 10 were ICA+ at the time of the first test but, 17 became ICA+ before diagnosis of IDDM. The interval between a positive test and the clinical diagnosis of IDDM varied between subjects (6-44 months, mean = 18.4 +/- 4.2 S.E. months) but it was less than 1 year in one subject. In addition to the higher risk of developing IDDM when ICA was positive, male sex and younger age of the subjects as well as young age of the index case and multiplex pedigrees were significant predictors of conversion to IDDM. The Cox's regression tree constructed using RECPAM identified three groups of varying rates of conversion to IDDM: (1) a group with the slowest progression characterized by ICA- and age of index case > 5 years or female sex (relative hazard = 1); (2) an intermediate progression group consisting of subjects who are ICA- and have both < 5 years of age and male sex (relative hazard = 8.78); (3) a group with the fastest progression consisting of subjects who are ICA+ (relative hazard = 31.45). From these results our data suggest that in addition to ICA, clinical markers such as age, sex and multiple pedigrees are also significant predictors of the rate of conversion to IDDM. Furthermore, screening for ICA in family intervention studies will have to be done frequently, perhaps yearly, and will have to be continued into adult life, particularly in ICA- subjects in order to identify the 85-90% of subjects who become ICA+ at the clinical diagnosis of IDDM.

Adolescent↗