Biomedical subjects

Jean Yves Mary

Publications and source records attributed to Jean Yves Mary.

5 recordsLinked to original sources

PubMed2007

Log-linear non-uniform association models for agreement between two ratings on an ordinal scale.

In agreement studies, when objects are rated independently by two raters (or twice by the same rater), an association between their ratings on two categories arises, reflecting the distinguishability of these two categories for these raters. When ratings are performed on an ordinal scale, this association between ratings on two categories increases when the distance between these categories increases on the ordinal scale. Goodman's log-linear models derived for the analysis of agreement between two raters on an ordinal scale assume that distinguishabilities between adjacent categories are either constant, or a priori fixed. Log-non-linear models that allow variations of the distinguishabilities between adjacent categories along the scale, may lead to difficulties in parameter estimation. This paper describes a new class of log-linear non-uniform association models. These models extend the log-linear uniform association model by allowing variations of distinguishability between adjacent categories (along the scale). These new models are used to analyse ordinal agreement between dermatologists when assessing the severity of different cutaneous signs of ageing on women faces.

Adult↗

PubMed2005

A meta-analysis on data from 575 patients with multiple myeloma randomly assigned to either high-dose therapy or conventional therapy.

Long-term results of high-dose therapy followed by autologous stem cell transplantation (HDT-ASCT) as the first-line treatment for patients with myeloma are still poorly reported. To gain further insight in the long-term benefits of first-line HDT-ASCT compared with conventional therapy in myeloma, we performed a meta-analysis of individual patient data. We selected randomized trials evaluating HDT-ASCT in patients with previously untreated myeloma from 1990 to 1998, all with a median follow-up of 5 years or more. Individual data of the 3 selected trials were obtained from the study authors. Outcomes were survival, treatment-related mortality, and time without symptoms of disease or toxicity of treatment (TWiST). Five hundred seventy-five patients were analyzed, including 435 deaths (104 months of median follow-up). Compared with conventional therapy and adjusting for prognostic covariates, HDT-ASCT did not significantly prolong long-term survival (stratified hazard ratio, 0.887; 95% confidence interval, 0.735-1.072). This was not modified by accounting for heterogeneity in baseline risks, in treatment of relapse, or in outcomes across trials. There was no evidence of interaction between treatment effect on survival and presentation features. In contrast, a mean gain of 14.5 months (95% confidence interval, 9.9-19.1 mo) in TWiST was observed in the HDT-ASCT group compared with conventional therapy. In conclusion, we showed only a trend toward a long-term survival benefit of HDT-ASCT over conventional therapy for first-line treatment of myeloma. However, HDT-ASCT clearly delayed time to relapse, with a resulting 14.5 months benefit in mean TWiST.

Adult↗

PubMed2005

Does data rounding-off influence reproducibility index estimates?

The intraclass correlation coefficient (ICC) is the reproducibility index commonly used to assess the reproducibility level of continuous data. Such data are collected with finite precision (i.e., a finite number of decimal digits corresponding to the level of data rounding-off error). We therefore investigated the consequences of having finite precision for data on ICC estimates, thus comparing ICC estimates in presence of rounding-off to those associated with data with infinite precision. As long as the rounding-off level is less than 0.3sigmaX (where sigmaX is the standard deviation of the outcome measured), there is no practical consequence on the ICC estimate. Therefore, in most practical situations the consequences of rounding-off data on the estimation of reproducibility levels can be ignored.

Data Collection↗

PubMed2004

Single-dose perinatal nevirapine plus standard zidovudine to prevent mother-to-child transmission of HIV-1 in Thailand.

BACKGROUND: Although zidovudine prophylaxis decreases the rate of transmission of the human immunodeficiency virus (HIV) type 1 substantially, a large number of infants still become infected. We hypothesized that the administration, in addition to zidovudine, of a single dose of oral nevirapine to mothers during labor and to neonates would further reduce transmission of HIV. METHODS: We conducted a randomized, double-blind trial of three treatment regimens in Thai women who were receiving zidovudine therapy during the third trimester of pregnancy. In one group, mothers and infants received a single dose of nevirapine (nevirapine-nevirapine regimen); in another, mothers and infants received nevirapine and placebo, respectively (nevirapine-placebo regimen); and in the last, mothers and infants received placebo (placebo-placebo regimen). The infants also received one week of zidovudine therapy and were formula-fed. The end point of the study was infection with HIV in the infants, established by virologic testing. RESULTS: Between January 15, 2001, and February 28, 2003, a total of 1844 Thai women were enrolled. At the first interim analysis, the independent data monitoring committee stopped enrollment in the placebo-placebo group. Among women who delivered before the interim analysis, the as-randomized Kaplan-Meier estimates of the transmission rates were 1.1 percent (95 percent confidence interval, 0.3 to 2.2) in the nevirapine-nevirapine group and 6.3 percent (95 percent confidence interval, 3.8 to 8.9) in the placebo-placebo group (P<0.001). The final per-protocol transmission rate in the nevirapine-nevirapine group, 1.9 percent (95 percent confidence interval, 0.9 to 3.0), was not significantly inferior to the rate in the nevirapine-placebo group (2.8 percent; 95 percent confidence interval, 1.5 to 4.1). Nevirapine had an effect within subgroups defined by known risk factors such as viral load and CD4 count. No serious adverse effects were associated with nevirapine therapy. CONCLUSIONS: A single dose of nevirapine to the mother, with or without a dose of nevirapine to the infant, added to oral zidovudine prophylaxis starting at 28 weeks' gestation, is highly effective in reducing mother-to-child transmission of HIV.

Adult↗

PubMed2003

Reliability of antitransglutaminase antibodies as predictors of gluten-free diet compliance in adult celiac disease.

OBJECTIVE: Strict lifelong compliance to a gluten-free diet (GFD) minimizes the long-term risk of mortality, especially from lymphoma, in adult celiac disease (CD). Although serum IgA antitransglutaminase (IgA-tTG-ab), like antiendomysium (IgA-EMA) antibodies, are sensitive and specific screening tests for untreated CD, their reliability as predictors of strict compliance to and dietary transgressions from a GFD is not precisely known. We aimed to address this question in consecutively treated adult celiacs. METHODS: In a cross-sectional study, 95 non-IgA deficient adult (median age: 41 yr) celiacs on a GFD for at least 1 yr (median: 6 yr) were subjected to 1) a dietician-administered inquiry to pinpoint and quantify the number and levels of transgressions (classified as moderate or large, using as a cutoff value the median gluten amount ingested in the overall noncompliant patients of the series) over the previous 2 months, 2) a search for IgA-tTG-ab and -EMA, and 3) perendoscopic duodenal biopsies. The ability of both antibodies to discriminate celiacs with and without detected transgressions was described using receiver operating characteristic curves and quantified as to sensitivity and specificity, according to the level of transgressions. RESULTS: Forty (42%) patients strictly adhered to a GFD, 55 (58%) had committed transgressions, classified as moderate (< or = 18 g of gluten/2 months; median number 6) in 27 and large (>18 g; median number 69) in 28. IgA-tTG-ab and -EMA specificity (proportion of correct recognition of strictly compliant celiacs) was 0.97 and 0.98, respectively, and sensitivity (proportion of correct recognition of overall, moderate, and large levels of transgressions) was 0.52, 0.31, and 0.77, and 0.62, 0.37, and 0.86, respectively. IgA-tTG-ab and -EMA titers were correlated (p < 0.001) to transgression levels (r = 0.560 and R = 0.631, respectively) and one to another (p < 0.001) in the whole patient population (r = 0.834, N = 84) as in the noncompliant (r = 0.915, N = 48) group. Specificity and sensitivity of IgA-tTG-ab and IgA-EMA for recognition of total villous atrophy in patients under a GFD were 0.90 and 0.91, and 0.60 and 0.73, respectively. CONCLUSIONS: In adult CD patients on a GFD, IgA-tTG-ab are poor predictors of dietary transgressions. Their negativity is a falsely secure marker of strict diet compliance.

Adolescent↗