French Prospective Cohort Study Research Articles

Clinical Trials Report

CLOSTRIDIUM DIFFICILE INFECtion, an important cause of nosocomial diarrhea, has also been reported to be an important cause of diarrhea in the community. A British cohort study identified C difficile as the third most common cause of infectious diarrhea in patients aged 75 years and older seen by general practitioners. A French prospective cohort study performed in outpatients to whom antibiotics were prescribed reported an incidence of C difficile–associated disease (CDAD) of 1.5% and estimated that up to 920 000 outpatients nationwide could potentially develop toxinogenic CDAD yearly. Recent data suggest that both the rates and severity of nosocomial CDAD are increasing. While the rates of CDAD in the community are much lower than in the hospital setting, the absolute number of cases in the community could be significant. Gastric acidity constitutes a major defense mechanism against ingested pathogens, and loss of the normal stomach acidity has been associated with colonization of the normally sterile upper gastrointestinal tract. Acidsuppressive agents such as proton pump inhibitors and H2-receptor antagonists (H2RAs) increase gastric pH and proton pump inhibitors have also been shown to affect leukocyte function, which may contribute to the reported associations with an increased risk of respiratory tract infections and enteric infections including hospitaland nursing home–acquired CDAD. The reported increase in the rates and severity of CDAD and the emergence of more virulent strains combined with the widespread use of proton pump inhibitors and other gastricsuppressive agents in the general population underscore the importance of evaluating their effect on the

A Nonlinear Model with Latent Process for Cognitive Evolution Using Multivariate Longitudinal Data

Cognition is not directly measurable. It is assessed using psychometric tests, which can be viewed as quantitative measures of cognition with error. The aim of this article is to propose a model to describe the evolution in continuous time of unobserved cognition in the elderly and assess the impact of covariates directly on it. The latent cognitive process is defined using a linear mixed model including a Brownian motion and time-dependent covariates. The observed psychometric tests are considered as the results of parameterized nonlinear transformations of the latent cognitive process at discrete occasions. Estimation of the parameters contained both in the transformations and in the linear mixed model is achieved by maximizing the observed likelihood and graphical methods are performed to assess the goodness of fit of the model. The method is applied to data from PAQUID, a French prospective cohort study of ageing.

Data on diabetes from the French cohort study in schizophrenia

To establish the impact of antipsychotic medication on the incidence of diabetes, we have analysed data from the prospective French Cohort study of mortality in schizophrenia. This generated a large database of 3470 patients with schizophrenia initially enrolled in 1993 for which data collection on comorbidity has been collected systematically every three years since. The primary objective of the study was to evaluate the mortality rate in the study cohort. From this database, the prevalence and incidence of diabetes can be studied. In 1993, nine patients in 10 were prescribed conventional antipsychotics and the remainder amisulpride and clozapine. Since the introduction of risperidone and olanzapine, atypical antipsychotics are now used in one-third of patients. Multiple antipsychotic medications are used in many patients, with the exception of those receiving clozapine. At inclusion, 2.2% of patients in the study cohort had a diagnosis of diabetes. Morbidity rates were higher in females than in males (3.4% and 1.6%, respectively) and it was only in females that the standard morbidity ratio with respect to the general population was significantly elevated (2.2; 95% confidence intervals: 1.6 and 2.9). The prevalence of diabetes in the study cohort rose over the course of the study. Multivariate regression analysis was performed in order to identify potential determinants of diabetes. For pre-existing diabetes, four factors were identified: age at first hospitalisation, age, obesity and duration of schizophrenia. The same factors with the exception of length of illness were identified for the incident cases. There was no evidence for an interaction between the class and type of antipsychotic medication and risk of treatment emergent diabetes. However, the use of multiple antipsychotic treatments makes the individualisation of specific risks associated with any other antipsychotic drug impossible.

The contributing factors to medical cost of epilepsy: an estimation based on a French prospective cohort study of patients with newly diagnosed epileptic seizures (the CAROLE study)

Epilepsy is a common neurological condition with significant resource implications. An estimation was performed in France of the direct medical cost of patients presented with newly diagnosed seizures and followed during the first two years after diagnosis. This estimation was based on the service utilization data collected from French prospective cohort study (CAROLE: 1942 patients enrolled). Costs were estimated in a societal perspective in 1998 value. The impact on the costs of different factors like age, aetiologic categorization and severity of seizures (type and number of seizures), and treatment by anti-epileptic drugs (AEDs) was analysed. The mean annual direct epilepsy-related costs per patient were estimated to be 14 305 F and 3766 F for the first and the second year of follow-up respectively, 68% and 40% of the costs were devoted to inpatient care. Costs during the first year were highly sensitive to aetiologic categorization of seizures at inclusion and to other clinical parameters. Second-year costs had a much lower variance and were sensitive to frequency of seizures and the fact of being treated or not by AEDs. Our data emphasize the importance of seizure control as means of reducing the costs of epilepsy especially during the first year of follow-up.

Timing of mother-to-child HIV-1 transmission depends on maternal status. The HIV Infection in Newborns French Collaborative Study Group.

To estimate when mother-to-child transmission occurs and investigate the possible role of maternal factors. We studied virological data obtained in the first 3 months of life of 95 infected newborns born to HIV-1-seropositive mothers included in the French Prospective Cohort Study who did not breast-feed. Comparative Western blot analysis of sequential blood specimens from neonates and mothers with incomplete antibody patterns enabled us to detect antibody production in some infants. The results of viral investigation of neonate specimens enabled us to describe the acute phase of infection in newborns. Because the process between infection and antibody production is irreversible, we chose a Markov modelling technique, which is well suited for staged clinical processes. About two-thirds (65%) of the infants were considered to have been contaminated during delivery. In the remaining infants, the contamination was estimated to have occurred in utero and 95% of them had been infected less than 59 days before delivery. The association between the mother's immunological and virological status and the time of transmission was examined. The greater the degree of maternal immunodeficiency at delivery (in terms of p24 antigen and Western blot pattern) the higher the risk of in utero transmission, showing that vertical transmission is dependent on the mother's immunological status. These estimates should be considered when designing strategies to prevent mother-to-child transmission.