Biomedical subjects

C Binquet

Publications and source records attributed to C Binquet.

At least 19 recordsLinked to original sources

PubMed2007

Disability evolution in multiple sclerosis: how to deal with missing transition times in the Markov model?

Markov modeling of disability progression in multiple sclerosis requires knowledge of all times of transitions from a given level of disability to the next level, but such data are often missing. We address methodological challenges due to partly missing transition times. To estimate the effects of prognostic factors on the risk of transitions between three consecutive disability levels, two methods were used to deal with missing data. Listwise deletion limited the analysis to subjects with complete data. Multiple imputation of missing data revealed that data were missing at random (MAR mechanism) and imputed the missing transition times from the Weibull model. The results were then compared with the full data set with the actual times established through chart review. Multiple imputation estimates were systematically closer to those from the full data set than the listwise deletion estimates.

Adult↗

PubMed2006

The prognostic value of initial relapses on the evolution of disability in patients with relapsing-remitting multiple sclerosis.

The evolution of multiple sclerosis (MS) and the resulting disability are unpredictable. To identify clinical variables that could be potential prognostic factors, we followed a cohort of 288 patients diagnosed as having relapsing-remitting MS between 1990 and 2003. The end point was the first occurrence of a non-reversible EDMUS-GS score >or=3 (moderate disability). The impact of the number of MS attacks during the first 2 years of the disease as well as the first interattack interval were assessed in two Cox models, one using a fixed-in-time covariate, the other using a time-dependent covariate. Older age at onset and a higher number of MS attacks during the first 2 years of MS proved to be predictors of unfavourable prognosis. The first interattack interval had no influence on the evolution of the disability, conversely to the first relapse which had a short-term impact on the prognosis. We confirmed that the age at onset and the number of MS attacks during the first 2 years of MS are predictors of the evolution of the disability and demonstrated the importance of using time-dependent covariates.

Adolescent↗

PubMed2005

Management and prognosis of esophageal cancers: has progress been made?

The aim of this study was to investigate time trends in treatment and prognosis of esophageal cancer in a well-defined French population. Data was obtained from the Burgundy Cancer Registry (France) and three time periods were defined: 1976-90, 1991-96 and 1997-2002. A logistic regression was used to identify factors associated with an R0 resection. A multivariate survival analysis was performed using a Cox model. From 1976 to 2002, 2267 patients were included. The R0 resection rate slightly increased from 20.9% to 25.8% (P=0.019) then remained stable. Operative mortality decreased from 11.7% to 6.7% (NS). Age and subsite significantly influenced the rate of resection for cure whereas period had no effect. Chemotherapy alone was seldom used and radiotherapy alone dramatically dropped over time. Chemoradiation used as adjuvant treatment increased from 16.3% (1976-90) to 30.6% (1997-02) (P<0.001) and as sole treatment from 16.0% to 48.5% (P<0.001). The 3-year survival rates were respectively 10.1% and 9.7% (NS). Age and stage at diagnosis influenced the prognosis of esophageal cancer whereas time period and histology had no influence. This study claims that esophageal cancer remains a serious cancer problem and no improvement has been seen in the study population in France in its management over time.

Adenocarcinoma↗

PubMed2005

A population-based assessment of the prognostic value of the CD19 positive lymphocyte count in B-cell chronic lymphocytic leukemia using Cox and Markov models.

No population-based study has assessed the prognostic impact on survival of the CD19 positive lymphocyte count, evaluated by immunophenotyping at diagnosis, in B-cell chronic lymphocytic leukemia (B-CLL). Aiming at addressing this issue, we investigated the clinical outcome of a well-defined population of B-CLL patients. Survival of B-CLL patients, diagnosed between 1990 and 1999 and recorded by the Registry of Hematological Malignancies of the Côte d'Or, was analysed applying Cox's regression model to the 237 included cases and to the 195 Binet stage A patients. To assess simultaneously the predictive value of each parameter on the risk of disease progression and on the risk of death, we completed this analysis by applying a three-states homogeneous Markov model to the whole study population. Analysis of the entire population showed that age (p < 0.001), Binet stage (p = 0.008) and CD19 positive lymphocyte count (p = 0.038) were three independent prognostic factors. However, in stage A patients, only progression into a more advanced stage, analysed as a time-dependent variable, and age had a clear impact on survival (p < 0.001 for both). Markov model revealed that an increased CD19 positive lymphocyte count increased the risk of disease progression in stage A patients (p = 0.002) but did not have direct impact on survival of either stage A patients with stable disease or stage B or C patients. An increased CD19 positive lymphocyte count at diagnosis is a marker of an increased risk of disease progression in stage A patients. Thus, it can be a useful tool for the clinical management of these patients.

Adult↗

PubMed2005

[Long term use of nCPAP therapy in sleep apnoea patients].

INTRODUCTION: Although obstructive sleep apnoea syndrome (OSAS) is usually a lifelong condition, little is known about compliance with nasal continuous positive airway pressure (nCPAP) over longer periods of follow up. METHODS: Long term acceptance of nCPAP was evaluated retrospectively using a survival analysis in 137 consecutive patients who started nCPAP therapy for OSAS between 1985 and 1993. RESULTS: During a mean follow-up of 9.2 +/- 4.7 years, 30 patients died, 5 were lost of follow-up and 30 patients stopped their treatment most of them during the first 5 years. In compliant patients, the median value of daily nCPAP use was 7.5 hours. Kaplan Meier analysis showed that 82% of patients were still using nCPAP at 5 years, 77% at 10 years and 61% at 15 years. Multivariate analysis showed that OSAS severity was an independent predictor of long-term nCPAP use. The rate of nCPAP acceptance at 10 years was 82% in patients with an apnoea-hypopnoea index (AHI) > or = 30 compared to 58% in patients with AHI < 30. CONCLUSION: nCPAP is a suitable long-term therapy for OSAS, particularly in patients with more severe disease, with more than 80% of patients continuing to be compliant with treatment at 10 years.

Aged↗

PubMed2005

[Congenital ocular toxoplasmosis--ocular manifestations and prognosis after early diagnosis of infection].

BACKGROUND: Congenital toxoplasmosis (CT) is the most frequently encountered congenital infection. The aim of the present review is to report about the long-term outcome of functional and morphological manifestations after an early confirmation of the diagnosis. PATIENTS AND METHODS: We report on a cohort of patients with serologically confirmed CT, born between 1988 and 2001, who were followed up prospectively at a single centre (Institute of Parasitology, Hôpital de la Croix Rousse, University of Lyon). All patients underwent regular ophthalmological, parasitological and paediatric controls on a half-yearly or annual basis. Ocular manifestations were documented and visual acuity was assessed as far as was possible. RESULTS: 1,506 seroconversions were diagnosed during pregnancy, and 327 of the live-born offspring were seropositive for CT. At the end of the study period, ocular manifestations occurred in 79 of the children (24 %), and in 7 cases (9 %) they were discovered during the first month of life. In 72 of the patients (91 %), the ocular manifestations developed between 1 and 151 months (median follow-up time: 6.3 +/- 3.7 years; range: 0.5 - 14 years) under medical treatment for the first year of life. At the end of the study period, information regarding visual acuity was available for 66 patients. In 55 of these (83 %), visual acuity was normal in both eyes, and in 11 (17 %), it was reduced below 0.5. In 1 child, both eyes were functionally affected, one severely. CONCLUSION: CT may not become manifest ocularly until after a decade, which underlines the necessity for long-term ophthalmological monitoring of the infected individuals. In our patients, the prognostic outcome after therapy for the first year of life was better than that reported in the literature. This favourable outcome may serve as a basis for patient counselling.

Adolescent↗

PubMed2005

Decision analysis for the assessment of a record linkage procedure: application to a perinatal network.

OBJECTIVES: According to European legislation, we must develop computer software allowing the linkage of medical records previously rendered anonymous. Some of them, like AUTOMATCH, are used in daily practice either to gather medical files in epidemiologic studies or for clinical purpose. In the first situation, the aim is to avoid homonymous errors, and in the second one, synonymous errors. The objective of this work is to study the effect of different parameters (number of identification variables, phonetic treatments of names, direct or probabilistic linkage procedure) on the reliability of the linkage in order to determine which strategy is the best according to the purpose of the linkage. METHODS: The assessment of the Burgundy Perinatal Network requires the linking of discharge abstracts of mothers and neonates, collected in all the hospitals of the region. Those data are used to compare direct and probabilistic linkage, using different parameterization strategies. RESULTS: If the linkage has to be performed in real time, so that no validation of indecisions generated by probabilistic linkage is possible, probabilistic linkage using three variables without any phonetic treatment seems to be the most appropriate approach, combined with a direct linkage using four variables applied to non-conclusive links. If a validation of indecisions is possible in an epidemiological study, probabilistic linkage using five variables, with a phonetic treatment adapted to the local language has to be preferred. For medical purpose, it should be combined with a direct linkage with four or five variables. CONCLUSION: This paper reveals that the time and money available to manage indecision as well as the purpose of the linkage are of paramount importance for choosing a linkage strategy.

France↗

PubMed2004

Modeling recurrence in colorectal cancer.

OBJECTIVE: To assess the role of recurrence in prognosis of colon cancer, we investigated several methodologic issues, including application of classic survival analysis and Markov model. STUDY DESIGN AND SETTING: The data were recorded by the Registry of Digestive Tumors of Côte d'Or, France, for 874 patients who had been treated by surgery between 1976 and 1984 and followed for up to 11 years. Survival analyses included the Cox proportional hazards model and its two generalizations that allow recurrence to be taken into account as a time-dependent covariate or as a competing outcome. The Markov model was used to analyze simultaneously recurrence and death. RESULTS: The competing risks approach is not appropriate because censoring is indisputably informative. The Markov model and the Cox model, with recurrence as a time-dependent covariate, provided similar results, demonstrating the impact of age and gender on recurrence and revealing a reduction in the effect of site and stage on mortality. CONCLUSION: A Markov multistate model seems to give new insights about the course of digestive cancer progression and into the role of recurrence in this process.

Age Factors↗

PubMed2004

[Assessment of the discriminating power of identifiers for record linkage].

BACKGROUND: To reconstruct a patient's medical history, one has often to combine information from different sources, whatever the context of this reconstitution: epidemiological studies or health care. As a linkage using less informative identifiers could lead to linkage errors, it is essential to quantify the information associated to each identifier. METHODS: The aim of this study was to estimate the discriminating power of different identifiers which could be used in a record linkage process based on the means of the likelihood ratio proposed by Jaro as a probabilistic record linkage method. Six identifiers were considered: date of birth, maiden name, usual last name, first and second christian names and the gender. Two types of phonetic treatment were taken into account: the Soundex and a phonetic treatment adapted to the French language. Three situations were considered: 1) and 2) linkage of the data collected during two consecutive years in a university hospital (CHU de Dijon; 100000x100000 records) and a Paris hospital (50000x50000 records), 3) linkage of two files obtained through a healthcare network (Burgundy Perinatal Network; 200x2500 records). RESULTS: Whatever the situation, this work showed the interest of three identifiers when linking data concerning a same patient. The date of birth had the best discriminating power followed by the first and the last names. Including a poorly discriminating identifier like gender did not improve the results. Moreover, adding a second Christian name, often missing, increased linkage errors. On the contrary, it seemed that using a phonetic treatment adapted to the French language could slightly improve the results of linkage in comparison to Soundex. CONCLUSION: Whatever the method used, it seems necessary to improve the quality of identifier collection, in particular of the date of birth and of the first and last names as it could make the linkage of data obtained from different sources easier. Further research is needed to estimate the discriminating power of other identifiers (birth place and parents identifiers).

Medical Record Linkage↗

PubMed2003

[Factor V Leiden and myocardial infarction: a case, review of the literature with a meta-analysis].

Mutation in blood coagulation factor V Leiden is the most frequently genetic polymorphism implied in venous thrombosis. A 57 year old man was hospitalised for acute myocardial infarction (MI). An emergency coronary angiography was performed, and no significant stenosis was observed. The haematologic check-up showed an heterozygous Leiden mutation of factor V. We report all publications about the relation between factor V Leiden and coronary thrombosis, and we performed a meta-analysis. We analysed the relation in general population and in subgroups, such as, younger and older, and patient with or without coronary stenosis. In global population, the meta-analysis did not found significant association between Factor V Leiden and myocardial infarction (OR = 1.25; IC = 0.97-1.58). In contrast, in patients less than < 55 years old after MI, Factor V Leiden prevalence was significantly higher than in control group (OR = 1.48; IC = 1.05-2.08). In addition, after MI without significant coronary stenosis Factor V Leiden prevalence was significantly higher than in normal patients (OR = 2.84; IC = 1.46-5.51). After MI, in patients without significant coronary stenosis, Factor V Leiden prevalence was significantly higher than in patients with significant coronary stenosis (OR = 3.26; IC = 1.67-6.36). Our study suggests that Factor V Leiden could be search after MI in young subjects and/or without significant stenosis.

Activated Protein C Resistance↗

PubMed2003

Prognostic factors for the long-term development of ocular lesions in 327 children with congenital toxoplasmosis.

The aim of this study was to identify the high-risk factors associated with the development of ocular lesions in a large cohort of children with congenital toxoplasmosis (CT), irrespective of their gestational age at the time of maternal infection. Children were managed according to a standardized protocol and monitored for up to 14 years at the Croix-Rousse Hospital, Lyon, France. Cox model and a flexible regression, spline-based method were used for the analysis. During a median follow-up time of 6 years, 79 of the 327 children (24%) had at least one retinochoroidal lesion. No bilateral impairment of visual acuity was observed. The risk of a child developing ocular disease was higher not only when mothers were infected early during pregnancy, which was expected, but also when CT was diagnosed prior to or at the time of birth, when non-ocular manifestations were present at baseline and when birth was premature.

Adolescent↗

PubMed2002

[Is subtotal bilateral thyroidectomy still indicated in patients with Grave's disease?].

AIM OF THE STUDY: To evaluate the morbidity and the functional results of subtotal bilateral thyroidectomy in patients (TST) with Graves' disease. PATIENTS AND METHOD: A retrospective study was performed in 128 patients. They were 23 males and 105 females with a median age of 34 years (range: 14-68). Weight of remnant tissue was between 4 and 5 g. Thyroid functional status was evaluated, at 3 months and after a follow-up period ranged from 1 to 5 years, by measurement of serum concentration of free T4 and/or free T3 and TSH. RESULTS: They were no post-operative death. Surgical complications were 2 vocal cord palsies and 17 hypocalcemia (inf. to 2 mmol/L). After a median follow-up of 2 years, they were no longer any cases of vocal cord dysfunction and no case of permanent hypoparathyroidism. Functional results were established in 118 patients: 46 patients had clinical hypothyroidism (39%), 64 patients had latent hypothyroidism or euthyroidism (54.2%), and 8 had recurrent hyperthyroidism (6.8%). CONCLUSION: These results suggest that TST with a remnant mass inferior to 5 g provides a low level of recurrent hyperthyroidism and allows to give no drug therapy to half patients. In our opinion, TST is still indicated in Graves' disease.

Adolescent↗

PubMed2002

[Evaluation of prevention strategies for congenital toxoplasmosis: a critical review of medico-economic studies].

BACKGROUND: Congenital toxoplasmosis (CT) may lead to serious neurological or sensory consequences. A serological screening of women at risk of acquiring toxoplasmosis became mandatory in France, first during the visit before wedding (1978), then during the visit for pregnancy declaration (1985) and at last with a monthly follow-up during pregnancy since 1992. The efficacy and the profitability of the program was never assessed, in spite of the modification of the epidemiological context. However medico-economical studies were conducted in countries in which no prevention program for CT was available to determine the interest of an antenatal screening similar to the French one or of other prevention strategies. METHODS: Eight studies comparing at least two strategies were selected. Methodologies used in those studies were analyzed by two independent readers with the help of a standardized scale. A score was calculated for each study. RESULTS: Each study analyzed suffered from methodological limitations, in particular concerning the estimation of antenatal treatment efficacy, which could lead to invalidate their conclusion. The most reliable studies in regard to methodological guidelines, that is with the higher score, concluded that antenatal screening was not contributive. However, they could not be transposed directly in the present French situation, because of the difference of the epidemiological and economical context. CONCLUSIONS: Given the difficulty to obtain a clear conclusion, it seems necessary to perform a rigorous decision analysis to identify the more effective and acceptable program in terms of human and financial costs for preventing congenital toxoplasmosis.

Cost-Benefit Analysis↗

PubMed2002

[A diagnostic strategy for isolated pulmonary nodules less than 2 cm in diameter].

The object of this study is to determine the best diagnostic strategy for isolated pulmonary nodules less than 2 cm in diameter starting from decision analysis. The diagnostic pathway included strategies: 1. Observation with a thoracic tomodensitometry (TDM) every 3 months. 2. Percutaneous needle biopsy. 3. Video-assisted thoracoscopic surgery (VATS) resection. 4. Resection by thoracotomy. Observation was the best strategy for non-smokers in their 40's with a cost of 57-69 Francs per year of life gained. Needle biopsy was the best strategy for a 1 cm nodule in patients of 50 years, smokers and non-smokers (life expectancy 29.38 and 24.44 years). The best strategy for a 2 cm nodule was needle biopsy in 40 year old smokers (life expectancy 34.18 years) and in non-smokers aged 50-60 years with a life expectancy from 20.0 to 28.2 years. VATS was the best strategy for a 1 cm nodule in smokers over the age of 60 for a 2 cm nodule over the age of 50. The costs were 1 811, 3 214, 1 873, 1 811 and 6 093 Francs respectively per year of life gained. During the sensitivity analysis VATS remained the best strategy provided the post-operative mortality remained below 2%. When the risk of malignancy is only moderate needle biopsy may be recommended but when the risk of malignancy is high it is preferable to advise VATS as the method of diagnosis.

Adult↗

PubMed2002

Assessing time-by-covariate interactions in relative survival models using restrictive cubic spline functions.

BACKGROUND: The Cox model is widely used in the evaluation of prognostic factors in clinical research. However, in population-based studies, which assess long-term survival of unselected populations, relative-survival models are often considered more appropriate. In both approaches, the validity of proportional hazards hypothesis should be evaluated. METHODS: We propose a new method in which restricted cubic spline functions are employed to model time-by-covariate interactions in relative survival analyses. The method allows investigation of the shape of possible dependence of the covariate effect on time without having to specify a particular functional form. Restricted cubic spline functions allow graphing of such time-by-covariate interactions, to test formally the proportional hazards assumption, and also to test the linearity of the time-by-covariate interaction. RESULTS: Application of our new method to assess mortality in colon cancer provides strong evidence against the proportional hazards hypothesis, which is rejected for all prognostic factors. The results corroborate previous analyses of similar data-sets, suggesting the importance of both modelling of non-proportional hazards and relative survival approach. We also demonstrate the advantages of using restricted cubic spline functions for modelling non-proportional hazards in relative-survival analysis. The results provide new insights in the estimated impact of older age and of period of diagnosis. DISCUSSION: Using restricted cubic splines in a relative survival model allows the representation of both simple and complex patterns of changes in relative risks over time, with a single parsimonious model without a priori assumptions about the functional form of these changes.

Aged↗

PubMed2001

Modeling changes in CD4-positive T-lymphocyte counts after the start of highly active antiretroviral therapy and the relation with risk of opportunistic infections: the Aquitaine Cohort, 1996-1997.

After initiation of a treatment for human immunodeficiency virus type 1 infection containing a protease inhibitor, immune restoration associated with increases in CD4-positive (CD4+) T lymphocyte count may be delayed. In a sample of patients who had been prescribed protease inhibitors for the first time, the authors tested to see whether there was a minimal duration of CD4+ cell count increase before the increase had an impact on the occurrence of opportunistic infections. The evolution (difference between time t and baseline) of CD4+ cell count was modeled using a mixed effects linear model. Changes in CD4+ count estimated by this model were then included as time-dependent covariates in a proportional hazards model. Finally, the authors tested for the existence of a CD4+ change x time interaction. The authors used a sample of 553 French patients first prescribed protease inhibitors in 1996 and followed for a median of 16 months. During the first 120 days, there was no association between CD4+ change and the rate of opportunistic infections. After 120 days, each 50-cell/mm3 increase in CD4+ count was associated with a 60% (95% confidence interval: 45, 72) reduction in the incidence of opportunistic infections. These results, based on modeling of CD4+ cell response, at least indirectly reinforce the concept of a delayed but possible immune recovery with the use of protease inhibitors. The findings support the potential for interruption of certain types of prophylaxis against opportunistic infections under reasonable conditions of duration of antiretroviral therapy and sustained CD4+ cell response.

AIDS-Related Opportunistic Infections↗

PubMed2001

[Medico-economic impact of the Program of Medicalization of the Information System on hospital stay for myocardial infarction: influence of the quality of data collection and hospitalization length].

The aim of the Medicalisation Program of the Information System was to describe the activity of hospital for budget allocation. This work concerned the whole hospitalizations in the unit of intensive care of cardiology of Dijon for a myocardial infarction (MI) during the 1st half of 1998 (59 patients). The objectives of this study were: 1) the estimate of the real cost of MI management; 2) the comparison of this cost with the reference cost, determined from the data of the National Basis of Costs (BNC); 3) the economic impact of the quality of coding. The real global cost of MI was estimated at 2,323,542 FF (average by patient: 39,382 +/- 15,718 FF). Sixty eight per cent of the costs are directly related to the standing fixed overheads; in contrast, the medical and the therapeutic acts accounted for only 32% of the estimated real cost. A 52% over-estimation was highlighted between the estimated real cost and the cost of reference (p < 0.001). The errors of coding accounted for an under-estimation of only 3.6% of the cost of reference. The duration of hospitalization was significantly higher than the stay length taken from the national reference database (12.9 +/- 5.4 versus 9.2 +/- 2.1 days; p < 0.001), and was mainly responsible for these discrepancies of costs.

Costs and Cost Analysis↗

PubMed2001

[Using discharge abstracts as a tool to assess a regional perinatal network].

To assess the regional perinatal network of Burgundy (20 obstetrical units; 18,000 births/year), discharge abstracts are collected for all mothers and all neonates. Discharge abstracts are expanded with some additional data. According to the French law, data are rendered anonymous in each hospital before their transmission to the teaching hospital for statistical analysis. The linkage of all anonymous information concerning a patient is obtained. Moreover, this specific procedure allows the linkage of data concerning each mother and her corresponding neonate. This study shows that after an expanded data quality control, the linkage between data of the mothers and their infants is obtained in 99.8% of births.

Adult↗