MR Imaging-Based Radiomic Signatures of Distinct Molecular Subgroups of Medulloblastoma.

BACKGROUND AND PURPOSE: Distinct molecular subgroups of pediatric medulloblastoma confer important differences in prognosis and therapy. Currently, tissue sampling is the only method to obtain information for classification. Our goal was to develop and validate radiomic and machine learning approaches for predicting molecular subgroups of pediatric medulloblastoma. MATERIALS AND METHODS: In this multi-institutional retrospective study, we evaluated MR imaging datasets of 109 pediatric patients with medulloblastoma from 3 children's hospitals from January 2001 to January 2014. A computational framework was developed to extract MR imaging-based radiomic features from tumor segmentations, and we tested 2 predictive models: a double 10-fold cross-validation using a combined dataset consisting of all 3 patient cohorts and a 3-dataset cross-validation, in which training was performed on 2 cohorts and testing was performed on the third independent cohort. We used the Wilcoxon rank sum test for feature selection with assessment of area under the receiver operating characteristic curve to evaluate model performance. RESULTS: Of 590 MR imaging-derived radiomic features, including intensity-based histograms, tumor edge-sharpness, Gabor features, and local area integral invariant features, extracted from imaging-derived tumor segmentations, tumor edge-sharpness was most useful for predicting sonic hedgehog and group 4 tumors. Receiver operating characteristic analysis revealed superior performance of the double 10-fold cross-validation model for predicting sonic hedgehog, group 3, and group 4 tumors when using combined T1- and T2-weighted images (area under the curve = 0.79, 0.70, and 0.83, respectively). With the independent 3-dataset cross-validation strategy, select radiomic features were predictive of sonic hedgehog (area under the curve = 0.70-0.73) and group 4 (area under the curve = 0.76-0.80) medulloblastoma. CONCLUSIONS: This study provides proof-of-concept results for the application of radiomic and machine learning approaches to a multi-institutional dataset for the prediction of medulloblastoma subgroups.

Vitamin B12 Deficiency Induced by the Use of Gastric Acid Inhibitors: Calcium Supplements as a Potential Effect Modifier.

OBJECTIVE: Use of gastric acid inhibitors has emerged as a risk factor of vitamin B12 deficiency, especially in older adults. Calcium supplements could be an effect modifier of this relationship by its role in the absorption process of vitamin B12. The aim of this study is to examine whether the use of calcium supplements could be an effect modifier of the association between gastric acid inhibitors and vitamin B12 deficiency. DESIGN: Cross-sectional study based on medical chart reviews. SETTING: Geriatric Assessment Unit (GAU) of a university-affiliated hospital. PARTICIPANTS: The study included 172 patients discharged from the GAU between 2008 and 2012. MEASUREMENTS: Cases of vitamin B12 deficiency were identified as those who had received a diagnosis of vitamin B12 deficiency, and/or were receiving a treatment for vitamin B12 deficiency. Use of gastric acid inhibitors and calcium supplements at admission was determined from the pharmacist report. Associations between medications and vitamin B12 status were investigated using logistic regression models. RESULTS: Seventy-one patients (41%) had vitamin B12 deficiency. At admission, 42% were taking gastric acid inhibitors and 45% calcium supplements. After adjustment for covariates, analyses revealed that vitamin B12 deficiency was more likely among users of gastric acid inhibitors who did not concomitantly received calcium supplements [OR=3.12; P=0.01]. Conversely, no significant association was observed in patients using both, gastric acid inhibitors and calcium supplements [OR=1.30; P=0.59]. CONCLUSIONS: The present study provides the very first evidence that the use of calcium supplements could be an effect modifier of the association between gastric acid inhibitors and vitamin B12 deficiency. Failure to consider calcium supplements as an effect modifier could have led to biased risk estimates in previous published studies.

The use of basiliximab-infliximab combination for the treatment of severe gastrointestinal acute GvHD.

After allogeneic stem cell transplant, severe grade III-IV gastrointestinal (GI) acute GvHD is associated with significant morbidity and mortality, and generally results in poor outcomes. Salvage therapy for patients who fail steroid therapy is not well defined in the literature. In the current retrospective study, we reviewed our experience with the combination of basiliximab and infliximab in 21 patients with severe, grade III-IV GI acute GvHD of whom 16 met the definition for steroid-refractory disease. The overall response rate was 76%, with 43% CR at a median time of 21 days after beginning treatment. The survival at 1 year was 24%, with most deaths due to complications from GvHD and recurrence of primary disease. All five of the long-term survivors have chronic GvHD. On the basis of a review of the literature, this regimen does not seem to be significantly more effective than other strategies for severe GI GvHD and seems to be worse than the results reported for basiliximab alone. Future studies of single-agent basiliximab and newer agents are required.

Patterns of oral anticoagulants use in atrial fibrillation.

BACKGROUND: Novel oral anticoagulants are available for the management of atrial fibrillation and are considered more convenient to use than warfarin. OBJECTIVE: The main objective of this study was to describe patterns of oral anticoagulant use in the 6 months period following the availability of dabigatran at our hospital. METHODS: A cross-sectional study was conducted in a single University hospital in the province of Québec, Canada. Medical records of subjects on oral anticoagulants for atrial fibrillation that were hospitalized between October 1st, 2011 and March 31th, 2012 were reviewed. Type of use (prevalent, incident and switch) and patient's characteristics of warfarin and dabigatran users were compared using Chi-squared and T-tests. RESULTS: In the 6-month period following dabigatran availability in the hospital, 59 patients (13%) were on dabigatran and 388 (87%) on warfarin. Mean CHADS2 score, mean age and mean number of chronic medications were lower in the dabigatran group. The percentage of patients with coronary artery disease was lower and renal function was higher in the dabigatran group. CONCLUSION: Dabigatran use remained low in the first 6 months period following the approval of dabigatran at our hospital, which could be explained by limited data on the efficacy and safety of this agent in subjects with multiple comorbidities.

MRI surrogates for molecular subgroups of medulloblastoma.

BACKGROUND AND PURPOSE: Recently identified molecular subgroups of medulloblastoma have shown potential for improved risk stratification. We hypothesized that distinct MR imaging features can predict these subgroups. MATERIALS AND METHODS: All patients with a diagnosis of medulloblastoma at one institution, with both pretherapy MR imaging and surgical tissue, served as the discovery cohort (n = 47). MR imaging features were assessed by 3 blinded neuroradiologists. NanoString-based assay of tumor tissues was conducted to classify the tumors into the 4 established molecular subgroups (wingless, sonic hedgehog, group 3, and group 4). A second pediatric medulloblastoma cohort (n = 52) from an independent institution was used for validation of the MR imaging features predictive of the molecular subtypes. RESULTS: Logistic regression analysis within the discovery cohort revealed tumor location (P < .001) and enhancement pattern (P = .001) to be significant predictors of medulloblastoma subgroups. Stereospecific computational analyses confirmed that group 3 and 4 tumors predominated within the midline fourth ventricle (100%, P = .007), wingless tumors were localized to the cerebellar peduncle/cerebellopontine angle cistern with a positive predictive value of 100% (95% CI, 30%-100%), and sonic hedgehog tumors arose in the cerebellar hemispheres with a positive predictive value of 100% (95% CI, 59%-100%). Midline group 4 tumors presented with minimal/no enhancement with a positive predictive value of 91% (95% CI, 59%-98%). When we used the MR imaging feature-based regression model, 66% of medulloblastomas were correctly predicted in the discovery cohort, and 65%, in the validation cohort. CONCLUSIONS: Tumor location and enhancement pattern were predictive of molecular subgroups of pediatric medulloblastoma and may potentially serve as a surrogate for genomic testing.

Time-dependent structural changes of the dentatothalamic pathway in children treated for posterior fossa tumor.

BACKGROUND AND PURPOSE: Injury to the dentatothalamic pathway that originates in the cerebellum has been suggested as a mechanism for neurologic complications in children treated for posterior fossa tumors. We hypothesized that time-dependent changes occur in the dentatothalamic pathway. MATERIALS AND METHODS: Diffusion tensor evaluation was performed in 14 children (median age, 4.1 years; age range, 1-20 years) who underwent serial MR imaging at 3T as part of routine follow-up after posterior fossa tumor resection with or without adjuvant therapy. Tensor metrics were obtained in the acute (≤1 week), subacute (1 to <6 months), and chronic (≥6 months) periods after surgery. We evaluated the following dentatothalamic constituents: bilateral dentate nuclei, cerebellar white matter, and superior cerebellar peduncles. Serial dentate nuclei volumes were also obtained and compared with the patient's baseline. RESULTS: The most significant tensor changes to the superior cerebellar peduncles and cerebellar white matter occurred in the subacute period, regardless of the tumor pathology or therapy regimen, with signs of recovery in the chronic period. However, chronic volume loss and reduced mean diffusivity were observed in the dentate nuclei and did not reverse. This atrophy was associated with radiation therapy and symptoms of ataxia. CONCLUSIONS: Longitudinal diffusion MR imaging in children treated for posterior fossa tumors showed time-dependent tensor changes in components of the dentatothalamic pathway that suggest evolution of structural damage with inflammation and recovery of tissue directionality. However, the dentate nuclei did not show tensor or volumetric recovery, suggesting that the injury may be chronic.

The role of community pharmacists in the prevention and management of osteoporosis and the risk of falls: results of a cross-sectional study and qualitative interviews.

UNLABELLED: In a mailed survey and qualitative interviews, it was observed that community pharmacists and public health authorities believe that pharmacists should play a significant role in the prevention and management of osteoporosis and the risk of falls. However, pharmacists acknowledge a wide gap between their ideal and actual levels of involvement. INTRODUCTION: The aim of this study was to explore perceptions of community pharmacists and public health authorities regarding the role of pharmacists in providing services in relation to osteoporosis and risk of falls and the barriers to providing them. METHODS: Using a modified five-step version of Dillman's tailored design method, a questionnaire was mailed to a random sample of 1,250 community pharmacists practicing in Montreal (Quebec, Canada) and surrounding areas. A similar questionnaire was sent to public health officers in these regions. Additionally, telephone interviews were conducted with regional and ministry level public health officers. RESULTS: Of the 1,250 pharmacists contacted, 28 were ineligible. In all, 571 of 1,222 (46.7 %) eligible community pharmacists and all the public health officers returned the questionnaire. Six public health officers (five regional and one at ministry level) were interviewed. Most pharmacists believed they should be involved in screening for osteoporosis (46.6 %) and risk of falls (50.3 %); however, fewer reported actually being involved in such services (17.4 % and 19.2 %, respectively). In their view, the main barriers to providing these services in current practice were lack of time (78.8 %), lack of clinical tools (65.4 %), and lack of coordination with other healthcare professionals (54.5 %). Public health authorities also thought community pharmacists should play a significant role in providing osteoporosis and fall risk services. However, few community pharmacist-mediated activities are in place in the participating regions. CONCLUSIONS: Although community pharmacists and public health authorities believe pharmacists should play a significant role with regard to osteoporosis and the risk of falls, they acknowledge a wide gap between the ideal and actual levels of pharmacist involvement.

Effect of treatment gaps in elderly patients with dementia treated with cholinesterase inhibitors.

OBJECTIVE: To determine the effect of treatment gaps on the risk of institutionalization or death among community-dwelling elderly patients treated with cholinesterase inhibitors (ChIs). METHODS: A survival analysis was conducted among a cohort of community-dwelling elderly patients (age 66+) newly treated with ChIs identified in the Quebec drug claims databases (Régie de l'Assurance Maladie du Québec [RAMQ]) between January 1, 2000, and December 31, 2007. Treatment nonpersistence during the year following ChI initiation was defined as treatment discontinuation or gaps of at least 6 weeks. To account for reverse causality, Cox proportional hazard modeling was conducted only among patients who did not discontinue treatment, in order to assess the association between treatment nonpersistence and institutionalization or death. RESULTS: Among the 24,394 elderly ChI users, 4,108 (16.8) experienced a treatment gap during the year following ChI treatment initiation while 596 (2.4%) discontinued their treatment within the first 3 months (early stoppers) and 4,038 (16.6%) after 3 months of treatment (late stoppers). Of all treated patients, 4,409 (18.1%) were institutionalized or died during follow-up. In patients who did not stop their treatment, the risk of institutionalization or death appeared lower in patients who experienced a treatment gap (hazard ratio 0.91; 95% confidence interval 0.86-0.96). CONCLUSIONS: Our results suggest that, contrary to what was previously reported in clinical trials, treatment gaps do not compromise the outcome of patients treated with ChIs in a real-life setting.

Exposure to anti-infective drugs during pregnancy and the risk of small-for-gestational-age newborns: a case-control study.

OBJECTIVE: To determine the association between anti-infective exposure during the last two trimesters of pregnancy and the risk of small-for-gestational-age (SGA) newborns. DESIGN: Case-control study within the Québec Pregnancy Registry. SETTING: Province of Québec, Canada. SAMPLE: Analyses were performed on prospectively collected data of 63,338 pregnant women that met eligibility criteria for the study (8192 cases and 55,146 controls). METHODS: Unconditional logistic regression models were used to quantify the association between exposure to anti-infective drugs and the risk of SGA. MAIN OUTCOME MEASURES: A case of SGA was defined as a pregnancy resulting in a baby that weighs below the tenth percentile, adjusted for gestational age and gender, according to the Canadian gender-specific reference curves. A control was defined as a pregnancy resulting in a baby that weighs greater or equal to the tenth percentile, adjusted for gestational age and gender. RESULTS: Exposure to all combined anti-infective drugs was not associated with the risk of SGA (OR 0.97; 95% CI 0.91-1.04). The use of sulfamethoxazole/trimethoprim was associated with SGA (OR 1.61; 95% CI 1.16-2.23), whereas the use of urinary anti-infective drugs decreased the risk (OR 0.80; 95% CI 0.65-0.97). CONCLUSIONS: Exposure to sulfamethoxazole/trimethoprim during the last two trimesters of pregnancy was associated with SGA. Further research is needed to address the use of other therapeutic alternatives in the management of infections that predispose infants being born SGA in pregnant women with other risk factors for this condition.

Effectiveness of interventions to improve the detection and treatment of osteoporosis in primary care settings: a systematic review and meta-analysis.

This study aims to evaluate the effectiveness of primary care interventions to improve the detection and treatment of osteoporosis. Eight electronic databases and six gray literature sources were searched. Randomized controlled trials, controlled clinical trials, quasi-randomized trials, controlled before-after studies, and interrupted time series written in English or French from 1985 to 2009 were considered. Eligible studies had to include patients at risk (women ≥ 65 years, men ≥ 70 years, and men/women ≥ 50 years with at least one major risk factor for osteoporosis) or at high risk (men/women using oral glucocorticoids or with previous fragility fractures) for osteoporosis and fractures. Outcomes included bone mineral density (BMD) testing, osteoporosis treatment initiation, and fractures. Data were pooled using a random effects model when applicable. Thirteen studies were included. The majority were multifaceted and involved patient educational material, physician notification, and/or physician education. Absolute differences in the incidence of BMD testing ranged from 22% to 51% for high-risk patients only and from 4% to 18% for both at-risk and high-risk patients. Absolute differences in the incidence of osteoporosis treatment initiation ranged from 18% to 29% for high-risk patients only and from 2% to 4% for at-risk and high-risk patients. Pooling the results of six trials showed an increased incidence of osteoporosis treatment initiation (risk difference (RD) = 20%; 95% CI: 7-33%) and of BMD testing and/or osteoporosis treatment initiation (RD = 40%; 95% CI: 32-48%) for high-risk patients following intervention. Multifaceted interventions targeting high-risk patients and their primary care providers may improve the management of osteoporosis, but improvements are often clinically modest.

Impact of a primary care physician workshop on osteoporosis medical practices.

SUMMARY: Attendance at a fragility-fractures-prevention workshop by primary care physicians was associated with higher rates of osteoporosis screening and treatment initiation in elderly female patients and higher rates of treatment initiation in high-risk male and female patients. However, osteoporosis management remained sub-optimal, particularly in men. INTRODUCTION: Rates of osteoporosis-related medical practices of primary care physicians exposed to a fragility-fractures-prevention workshop were compared with those of unexposed physicians. METHODS: In a cluster cohort study, 26 physicians exposed to a workshop were matched with 260 unexposed physicians by sex and year of graduation. For each physician, rates of bone mineral density (BMD) testing and osteoporosis treatment initiation among his/her elderly patients 1 year following the workshop were computed. Rates were compared using multilevel logistic regression models controlling for potential patient- and physician-level confounders. RESULTS: Twenty-five exposed physicians (1,124 patients) and 209 unexposed physicians (9,663 patients) followed at least one eligible patient. In women, followed by exposed physicians, higher rates of BMD testing [8.5% versus 4.2%, adjusted OR (aOR) = 2.81, 95% CI 1.60-4.94] and treatment initiation with bone-specific drugs (BSDs; 4.8% vs. 2.4%, aOR = 1.95, 1.06-3.60) were observed. In men, no differences were detected. In patients on long-term glucocorticoid therapy or with a previous osteoporotic fracture, higher rates of treatment initiation with BSDs were observed in women (12.0% vs. 1.9%, aOR = 7.38, 1.55-35.26), and men were more likely to initiate calcium/vitamin D (5.3% vs. 0.8%, aOR = 7.14, 1.16-44.06). CONCLUSIONS: Attendance at a primary care physician workshop was associated with higher rates of osteoporosis medical practices for elderly women and high-risk men and women. However, osteoporosis detection and treatment remained sub-optimal, particularly in men.

Better adherence to antihypertensive agents and risk reduction of chronic heart failure.

AIMS: Antihypertensive (AH) agents have been shown to reduce the risk of major cardiovascular events including chronic heart failure (CHF). However, the impact of changes in patterns of AH agents use on CHF is unknown. Our objective was to estimate to which different patterns of AH agent use is associated with the occurrence of CHF in a population-based study. METHOD AND RESULTS: A cohort of 82 320 patients was reconstructed using the Régie de l'assurance maladie du Québec's databases. Patients were eligible if they were between 45 to 85 years of age, had no indication of cardiovascular disease and were newly treated with AH therapy between 1999 and 2004. A nested case-control design was used to study the occurrence of CHF. Every case of CHF was matched for age and duration of follow-up to a maximum of 15 randomly selected controls. Adherence level was reported as a medication possession ratio. Conditional logistic regression models were used to estimate the rate ratio (RR) of CHF adjusting for different covariables. The mean patient age was 65 years, 37% were male, 8% had diabetes, 19% had dyslipidaemia and mean time of follow-up at 2.7 years. High adherence level (95%) to AH therapy compared with lower adherence level (60%) was associated with an additional reduction of CHF events (RR: 0.89; 0.80-0.99). Risk factors for CHF were being on social assistance, diabetes, dyslipidaemia, higher chronic disease score and developing a cardiovascular condition during follow-up. CONCLUSION: Our study suggests that a better adherence is associated with a significant risk reduction of CHF. Adherence to AH therapy needs to be improved to optimize benefits.

Control and severity of asthma during pregnancy are associated with asthma incidence in offspring: two-stage case-control study.

The extent to which childhood asthma incidence is influenced by asthma control and severity during pregnancy is unknown. We have studied this association during the child's first 10 yrs of life. A two-stage, case-control study, nested in a cohort of 8,226 children of asthmatic mothers, was conducted using three interlinked databases of Quebec, Canada, and mailed questionnaires. A total of 2,681 asthmatic children and 30,318 age-matched controls were selected (< or =20 controls.case(-1); stage 1), and 3,254 selected mothers were mailed questionnaires to obtain additional information (stage 2). Asthma control and severity was defined using validated indexes and childhood asthma incidence based on at least one asthma-related diagnosis and prescription received within 2 yrs. A total of 44 confounders were considered. Compared with children of mild controlled asthmatic mothers, children whose mothers had moderate-to-severe uncontrolled asthma during pregnancy had an increased risk of asthma (adjusted OR 1.27, 95% CI 1.06-1.52). No increased risk was observed for children of mild uncontrolled and moderate-to-severe controlled mothers. Based on one of the largest studies of children of asthmatic mothers, a significant increase in asthma risk was demonstrated among children whose mothers had poor control and increased severity of asthma during pregnancy, indicating that this element should be added to the expanding list of determinants of childhood asthma. As it constitutes a risk factor where pregnant asthmatic females can intervene, it is of great importance for physicians to optimally treat asthmatic females during pregnancy and to encourage females to be adherent to the prescribed asthma medications.

Comparison of direct health care costs related to the pharmacological treatment of osteoporosis and to the management of osteoporotic fractures among compliant and noncompliant users of alendronate and risedronate: a population-based study.

UNLABELLED: This population-based study aimed to compare direct health care costs related to the pharmacological treatment of osteoporosis and to the management of osteoporotic fractures among compliant and noncompliant users of alendronate and risedronate. During a 2-year follow-up period, compared to those with medication possession ratio (MPR) > or = 80%, women with MPR < 80% incurred significantly higher physician care costs and hospital care costs. INTRODUCTION: This study aimed to compare direct health care costs related to the treatment of osteoporosis and osteoporotic fractures among compliant and noncompliant users of alendronate and risedronate. METHODS: A cohort of 15,027 women having initiated alendronate or risedronate was identified. MPR and direct health care costs (physician care, hospital care, drugs) were assessed during a 2-year period. Regression models were used to estimate mean predicted cost for compliant (MPR > or = 80%) and noncompliant (MPR < 80%) women. RESULTS: Mean predicted physician care cost (in Canadian dollars) was $51 among women with MPR < 80% and $34 among those with MPR > or = 80%: mean difference $17, 95% confidence interval (CI) $2-22. Mean predicted hospital care cost was $568 among women with MPR < 80% and $379 among those with MPR > or = 80%: mean difference $189, 95% CI $56-320. Mean predicted drug cost was $439 among women with MPR < 80% and $1,068 among those with MPR > or = 80%: mean difference $-639, 95% CI $-649 to -629. CONCLUSION: Compared to compliant women, noncompliant women incurred significantly higher physician care and hospital care costs. Due to lower drug costs, total direct health care costs were lower among noncompliant women.

Individual variation in the frequency of sperm aneuploidy in humans.

To examine interindividual differences in sperm chromosome aneuploidy, repeated semen specimens were obtained from a group of ten healthy men, aged 20-21 at the start of the study, and analyzed by multi-color fluorescence in situ hybridization (FISH) analysis to determine the frequencies of sperm aneuploidy for chromosomes X, Y, 8, 18 and 21 and of diploidy. Semen samples were obtained three times over a five-year period. Statistical analysis examining the stability of sperm aneuploidy over time by type and chromosome identified two men who consistently exhibited elevated frequencies of sperm aneuploidy (stable variants): one with elevated disomy 18 and one with elevated MII diploidy. Differences among frequencies of aneuploidy by chromosome were also seen. Overall, disomy frequencies were lower for chromosome X, 8 and 18 than for chromosomes 21 or Y and for XY aneuploidy. The frequency of chromosome Y disomy did not differ from XY sperm frequency. Also, the frequency of meiosis I (XY) and II (YY + XX) sex chromosome errors did not differ in haploid sperm, but the frequency of MII errors was lower than MI errors in diploid sperm. Frequencies of sperm aneuploidy were similar between the first sampling period and the second, two years later. However, the frequency of some types of aneuploidy (XY, disomy Y, disomy 8, total autosomal disomies, total diploidy, and subcategories of diploidy) increased significantly between the first sampling period and the last, five years later, while others remained unchanged (disomy X, 21 and 18). These findings confirm inter-chromosome differences in the frequencies of disomy and suggest that some apparently healthy men exhibit consistently elevated frequencies of specific sperm aneuplodies. Furthermore, time/age-related changes in sperm aneuploidy may be detected over as short a period as five years in a repeated-measures study.

Persistence and determinants of statin therapy among middle-aged patients for primary and secondary prevention.

AIMS: Statins have been shown to significantly reduce morbidity and mortality in patients with coronary artery disease (CAD), and also in patients with dyslipidaemia when statins are taken regularly. Middle-aged patients have the highest level of forecasting benefit and little is known about persistence rate of these therapies in a real-life setting. The objective was to evaluate the persistence rate of middle-aged patients initiating a statin therapy and its relation with several determinants for primary and secondary prevention. METHODS: A cohort was reconstructed using the RAMQ databases. All patients aged 50-64 years-old who received at least one statin prescription between 1 January, 1998 and 31 December, 2000 for a new intention of treatment for dyslipidaemia were included in the cohort and followed up until 30 June, 2001. The date of the first prescription of statin was defined as the index date. There were 4316 patients in the secondary prevention (CAD diagnosis) and 13,642 patients in primary prevention cohort. The cumulative persistence rate was estimated using Kaplan-Meier, and Cox regression models were used to estimate the hazard ratio of ceasing statins. RESULTS: We found that persistence with statins had fallen to 71% after 6 months of treatment, and had declined to 45% after 3 years in the secondary prevention cohort; the corresponding figures were 65% and 35% in the primary prevention cohort. Our results suggest that patients with dyslipidaemia in primary prevention compared with those in secondary prevention (HR: 1.18; 1.11-1.25) are less likely to be persistent. Patients with other cardiovascular risk factors such as age (HR: 0.99; 0.98-0.99), diabetes (HR: 0.84; 0.79-0.90), hypertension (HR: 0.76; 0.72-0.80) were most likely to be persistent with statins. We observed lower persistence in patients who have used the greatest number of pharmacies and prescribing physicians. CONCLUSION: This analysis indicates that barriers to persistence occur early in the therapeutic course. Overall persistence with statins is low, and particularly among patients with few other cardiovascular risk factors.

Antiretroviral therapy effects on genetic and morphologic end points in lymphocytes and sperm of men with human immunodeficiency virus infection.

Many human immunodeficiency virus (HIV)-infected persons receive prolonged treatment with DNA-reactive antiretroviral drugs. A prospective study was conducted of 26 HIV-infected men who provided samples before treatment and at multiple times after beginning treatment, to investigate effects of antiretrovirals on lymphocyte and sperm chromosomes and semen quality. Several antiretroviral regimens, all including a nucleoside component, were used. Lymphocyte metaphase analysis and sperm fluorescence in situ hybridization were used for cytogenetic studies. Semen analyses included conventional parameters (volume, concentration, viability, motility, and morphology). No significant effects on cytogenetic parameters, semen volume, or sperm concentration were detected. However, there were significant improvements in sperm motility for men with study entry CD4 cell counts >200 cells/mm(3), sperm morphology for men with entry CD4 cell counts < or =200 cells/mm(3), and the percentage of viable sperm in both groups. These findings suggest that nucleoside-containing antiretrovirals administered via recommended protocols do not induce chromosomal changes in lymphocytes or sperm but may produce improvements in semen quality.

Factor analytic models of clustered multivariate data with informative censoring.

This article describes a general class of factor analytic models for the analysis of clustered multivariate data in the presence of informative missingness. We assume that there are distinct sets of cluster-level latent variables related to the primary outcomes and to the censoring process, and we account for dependency between these latent variables through a hierarchical model. A linear model is used to relate covariates and latent variables to the primary outcomes for each subunit. A generalized linear model accounts for covariate and latent variable effects on the probability of censoring for subunits within each cluster. The model accounts for correlation within clusters and within subunits through a flexible factor analytic framework that allows multiple latent variables and covariate effects on the latent variables. The structure of the model facilitates implementation of Markov chain Monte Carlo methods for posterior estimation. Data from a spermatotoxicity study are analyzed to illustrate the proposed approach.

Significance of incorporating measures of sperm production and function into rat toxicology studies.

The rat is the preferred species for reproductive toxicity testing. The inclusion of measures of rat sperm quality, such as motility and morphology, into reproductive test protocols often increases the sensitivity of the test to detect effects, and provides the toxicologist and risk assessor with valuable information about the nature of the reproductive toxicity of the test substance. Technical advances in computer-aided sperm analysis have made it possible to evaluate motion characteristics of rat spermatozoa. This technology can provide an objective means of classifying the motion of rat spermatozoa as progressive or non-progressive, as required in test protocols. More specific tests of rat sperm function are being applied for the purpose of evaluating modes and mechanisms of toxicant action. Computer-aided sperm analysis can be used to evaluate sperm motion during cultures that support sperm capacitation and to identify hyperactivated spermatozoa. Under the same culture conditions, acrosome-specific stains can be used to identify effects of toxicants on the acrosome reaction. These approaches, in combination with in vitro fertilization in rats, can pinpoint sperm functional deficits and thereby assist the toxicologist in addressing hypotheses regarding the cellular-molecular bases of toxicant-induced male infertility.

Pharmacokinetics of morphine and its glucuronidated metabolites in burn injuries.

OBJECTIVE: To investigate the effects of major thermal burn injury and continuous intravenous morphine infusion on the disposition of morphine and its glucuronidated metabolites, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) once a week for three weeks. CASE SUMMARIES: Five patients with major first-, second-, or third-degree burn injuries received long-term intravenous morphine infusion. The required dose varied greatly (from 4 to 39.5 mg/h). The steady-state concentrations of morphine, M3G, and M6G ranged from 20 to 452, 29 to 3436, and 20 to 1240 mumol/L, respectively. The systemic clearance (Cls) of morphine ranged from 14.8 to 40.3 mL/min/kg and did not change over time. The ratios of M6G and M3G to morphine were not affected by dose, even with the wide variation of intravenous dosage. Morphine kinetics appeared to be first-order. Mean recovery of morphine, M3G, and M6G in urine was 1.7 +/- 1.0%, 42.0 +/- 16.8%, and 11.8 +/- 3.2%, respectively, and renal clearance ranged from 8 to 64, 26 to 325, and 59 to 589 mL/min, respectively. Mean pain intensity ratings at rest remained low and stable (0.7 +/- 0.9 on day 7, 0.4 +/- 0.3 on day 14, 0 +/- 0 on day 21). DISCUSSION: To our knowledge, this is the first published report describing morphine, M3G, and M6G disposition in patients with major thermal burn injury. The Cls of morphine is similar to that observed in other patient populations and healthy subjects, suggesting that the presence of major burn injuries or a continuous morphine infusion over a three-week period may not contribute significantly to the variability among individuals. In these cases, the renal clearance of morphine and its glucuronides was within the range of values reported for other populations of patients and healthy subjects. Recovery of morphine and its glucuronides in urine was also similar to that in healthy individuals. CONCLUSIONS: These cases suggest that the effects of major burn injuries and of long-term intravenous infusion of morphine did not seem to modify morphine, M3G, and M6G disposition. Among patients with burn injuries, the severity of burns of duration of administration are not a cause of nonlinear kinetic of morphine or of morphine resistance. The morphine infusion rate was substantially variable and not directly related to its clearance, suggesting that monitoring of morphine should be focused on the clinical response.