Use of disease-modifying anti-rheumatic or anti-tumour necrosis factor drugs and risk of hospitalized infection in ankylosing spondylitis.

OBJECTIVE: To assess the risk of hospitalized infection among initiators of disease-modifying anti-rheumatic drugs (DMARDs) and/or anti-tumour necrosis factor (anti-TNF) agents in ankylosing spondylitis (AS). METHOD: We studied AS patients, new users of anti-TNF drugs and/or DMARDs between 1 January 2001 and 31 December 2011. Cohort entry was defined as the date of first prescription of any of these drugs. We used Cox regression with three time-varying drug exposures: current use of DMARDs without biologics, current use of anti-TNF agents alone or in combination with DMARDs (anti-TNF ± DMARDs), and current non-use. Models were adjusted for baseline patient sociodemographic characteristics, comorbidity, outpatient visits and procedures, previous infection, non-steroidal anti-inflammatory drugs, and corticosteroids. Hospitalized infection was defined on the basis of hospitalization discharge diagnoses (primary or non-primary) coding for infection. RESULTS: The cohort included 747 AS patients, with a mean age of 51.1 years (sd 14.6), and 466 (62.4%) were men. During the median follow-up of 1.98 years, 57 hospitalized infections occurred, for an incidence rate of 2.9/100 person-years. The adjusted hazard ratio of infection (relative to unexposed) was 1.00 [95% confidence interval (CI) 0.47-2.11] for the anti-TNF ± DMARDs group and 0.96 (95% CI 0.45-2.04) for DMARDs alone. Use of healthcare, corticosteroids, and previous hospitalized infections were associated with infection. CONCLUSION: We found no clear evidence that the risk of hospitalized infection was linked to DMARD and/or anti-TNF drug use. Because of scarce published literature on infection risk in AS patients, our results have important implications for clinicians.

A systematic review of observational studies of the association between pioglitazone use and bladder cancer.

AIM: To conduct a systematic review of all observational studies on the effect of pioglitazone on the risk of bladder cancer. METHODS: The MEDLINE and EMBASE databases were queried for papers published between 1 January 2000 and 30 October 2017. We took into consideration observational studies (both retrospective and prospective) that included participants with Type 2 diabetes prescribed anti-hyperglycaemic drugs. RESULTS: While some studies reported an association, others did not, and meta-analyses of these studies showed a significantly increased risk; however, while meta-analysis is a powerful and practical statistical tool, its results should be considered with caution when applied to widely heterogeneous studies. We describe how many of these studies are affected by different types of bias, most notably time-related biases, which should preclude a pooled analysis that would result in biased estimation of the risk. CONCLUSIONS: Given existing data, it is not appropriate to pool the outcomes of highly heterogeneous studies and further rigorously conducted observational research is needed to clarify the role of pioglitazone use on the incidence of bladder cancer.

Risk of lung cancer in relation to various metrics of smoking history: a case-control study in Montreal.

BACKGROUND: Few epidemiologic findings are as well established as the association between smoking and lung cancer. It is therefore somewhat surprising that there is not yet a clear consensus about the exposure-response relationships between various metrics of smoking and lung cancer risk. In part this is due to heterogeneity of how exposure-response results have been presented and the relative paucity of published results using any particular metric of exposure. The purposes of this study are: to provide new data on smoking-lung cancer associations and to explore the relative impact of different dimensions of smoking history on lung cancer risk. METHODS: Based on a large lung cancer case-control study (1203 cases and 1513 controls) conducted in Montreal in 1996-2000, we estimated the lifetime prevalence of smoking and odds ratios in relation to several smoking metrics, both categorical and continuous based on multivariable unconditional logistic regression. RESULTS: Odds ratios (ORs) for ever vs never smoking were 7.82 among males and 11.76 among females. ORs increased sharply with every metric of smoking examined, more so for duration than for daily intensity. In models using continuous smoking variables, all metrics had strong effects on OR and mutual adjustment among smoking metrics did not noticeably attenuate the OR estimates, indicating that each metric carries some independent risk-related information. Among all the models tested, the one based on a smoking index that integrates several smoking dimensions, provided the best fitting model. Similar patterns were observed for the different histologic types of lung cancer. CONCLUSIONS: This study provides many estimates of exposure-response relationships between smoking and lung cancer; these can be used in future meta-analyses. Irrespective of the histologic type of lung cancer and the smoking metric examined, high levels of smoking led to high levels of risk, for both men and women.

Visceral fat enhances blood pressure reactivity to physical but not mental challenges in male adolescents.

BACKGROUND: Excess visceral fat is a major risk factor for hypertension. Enhanced blood pressure (BP) reactivity and delayed BP recovery from physical and mental challenges predict future hypertension. OBJECTIVES: Determine whether visceral fat is associated with higher BP reactivity and delayed BP recovery from physical and mental challenges during adolescence. METHODS: In a community-based sample of 283 male and 308 female adolescents, we measured visceral fat with magnetic resonance imaging, total body fat with bioimpedance, and beat-by-beat BP with a Finometer at rest and during physical (10-min standing) and mental (2-min math stress) challenges. RESULTS: Males vs. females showed greater BP reactivity and no differences in BP recovery from either type of challenges. Visceral fat was positively associated with BP reactivity to standing up only and in males only (+8.4 ± 3.6 mmHg per 1 log cm(3) of visceral fat, P = 0.008), and this association was independent of total body fat. No association was seen between visceral fat and BP recovery from either type of challenge in either sex. All these associations were independent of age, puberty stage, height and initial BP. CONCLUSIONS: Adolescent males vs. females demonstrate greater BP reactivity but similar BP recovery from physical and mental challenges. Excess visceral fat enhances BP reactivity to physical but not mental challenges in males only.

Depression, depressive symptoms, and rate of hippocampal atrophy in a longitudinal cohort of older men and women.

BACKGROUND: Several studies have reported smaller hippocampal volume (HcV) in depression patients; however, the temporality of the association remains unknown. One proposed hypothesis is that depression may cause HcV loss. This study evaluates whether previous depression and recent depressive symptoms are associated with HcV and HcV loss. METHOD: We used a prospective cohort of older adults (n = 1328; age = 65-80 years) with two cerebral magnetic resonance imaging examinations at baseline and 4-year follow-up. Using multivariable linear regression models, we estimated, in stratified analyses by gender, the association between indicators of history of depression and its severity (age at onset, recurrence, hospitalization for depression), proximal depressive symptoms [Center for Epidemiologic Studies-Depression (CES-D) scale], baseline antidepressant use, and the outcomes: baseline HcV and annual percentage change in HcV. RESULTS: At baseline, women with more depressive symptoms had smaller HcV [-0.05 cm3, 95% confidence interval (CI) -0.1 to -0.01 cm3 per 10-unit increase in CES-D scores]. History of depression was associated with a 0.2% faster annual HcV loss in women (95% CI 0.01-0.36%). More baseline depressive symptoms and worsening of these symptoms were also associated with accelerated HcV loss in women. No associations were observed in men. Treatment for depression was associated with slower HcV loss in women and men. CONCLUSIONS: While only concomitant depressive symptoms were associated with HcV, both previous depression and more proximal depressive symptoms were associated with faster HcV loss in women.

Saguenay Youth Study: a multi-generational approach to studying virtual trajectories of the brain and cardio-metabolic health.

This paper provides an overview of the Saguenay Youth Study (SYS) and its parental arm. The overarching goal of this effort is to develop trans-generational models of developmental cascades contributing to the emergence of common chronic disorders, such as depression, addictions, dementia and cardio-metabolic diseases. Over the past 10 years, we have acquired detailed brain and cardio-metabolic phenotypes, and genome-wide genotypes, in 1029 adolescents recruited in a population with a known genetic founder effect. At present, we are extending this dataset to acquire comparable phenotypes and genotypes in the biological parents of these individuals. After providing conceptual background for this work (transactions across time, systems and organs), we describe briefly the tools employed in the adolescent arm of this cohort and highlight some of the initial accomplishments. We then outline in detail the phenotyping protocol used to acquire comparable data in the parents.

Left heart disease: a frequent cause of early pulmonary hypertension in systemic sclerosis, unrelated to elevated NT-proBNP levels or overt cardiac fibrosis but associated with increased levels of MR-proANP and MR-proADM: retrospective analysis of a French Canadian cohort.

OBJECTIVES: Pulmonary hypertension (PH) causes mortality in systemic sclerosis (SSc). Pulmonary arterial hypertension (PAH) and left heart disease (LHD) are frequent causes of PH. Therefore, we studied PAH and LHD in early PH. METHOD: A total of 432 French Canadian SSc patients were studied retrospectively. All underwent screening for PH. We analysed clinical, serological, and radiographic data from 26 patients with early PH diagnosed by right heart catheterization (RHC). SSc patients with (n = 21) and without PH (n = 19) were prospectively re-evaluated by cardiac magnetic resonance imaging (MRI) and serial measurements of N-terminal pro-brain natriuretic peptide (NT-proBNP) and the haemodynamic biomarkers mid-regional pro-atrial natriuritic peptide (MR-proANP) and mid-regional pro-adrenomedullin (MR-proADM). RESULTS: The most frequent cause of early PH was LHD (58%). PAH was seen in 34% of patients. No association was found between the type of PH and autoantibodies. Early LHD-PH, but not early PAH, was associated with lower NT-proBNP (p = 0.024), but MR-proANP and MR-proADM levels were higher in early LHD-PH than in patients without PH (p = 0.014 and p = 0.012, respectively). Only one patient had abnormal cardiac MRI explaining LHD-PH. CONCLUSIONS: Early PH in SSc, like late PH, is heterogeneous and RHC is essential for determining its underlying cause. The most frequent cause of early PH was LHD. Levels of MR-proANP and MR-proADM, but not NT-proBNP, were increased in early LHD-PH, and may be more reliable than NT-proBNP as a biomarker of early PH in this subgroup of patients. Cardiac MRI did not explain LHD-PH. This study is the first to identify a high frequency of LHD in early PH correlating with normal NT-proBNP levels but increased MR-proANP and MR-proADM levels in SSc patients.

Frequency of dosage prescribing medication errors associated with manual prescriptions for very preterm infants.

WHAT IS KNOWN AND OBJECTIVE: The risk of dosage Prescription Medication Error (PME) among manually written prescriptions within 'mixed' prescribing system (computerized physician order entry (CPOE) + manual prescriptions) has not been previously assessed in neonatology. This study aimed to evaluate the rate of dosage PME related to manual prescriptions in the high-risk population of very preterm infants (GA < 33 weeks) in a mixed prescription system. METHODS: The study was based on a retrospective review of a random sample of manual daily prescriptions in two neonatal intensive care units (NICU) A and B, located in different French University hospitals (Dijon and La Reunion island). Daily prescription was defined as the set of all drugs manually prescribed on a single day for one patient. Dosage error was defined as a deviation of at least ±10% from the weight-appropriate recommended dose. RESULTS AND DISCUSSION: The analyses were based on the assessment of 676 manually prescribed drugs from NICU A (58 different drugs from 93 newborns and 240 daily prescriptions) and 354 manually prescribed drugs from NICU B (73 different drugs from 131 newborns and 241 daily prescriptions). The dosage error rate per 100 manually prescribed drugs was similar in both NICU: 3·8% (95% CI: 2·5-5·6%) in NICU A and 3·1% (95% CI: 1·6-5·5%) in NICU B (P = 0·54). Among all the 37 identified dosage errors, the over-dosing was almost as frequent as the under-dosing (17 and 20 errors, respectively). Potentially severe dosage errors occurred in a total of seven drug prescriptions. None of the dosage PME was recorded in the corresponding medical files and information on clinical outcome was not sufficient to identify clinical conditions related to dosage PME. Overall, 46·8% of manually prescribed drugs were off label or unlicensed, with no significant differences between prescriptions with or without dosage error. The risk of a dosage PME increased significantly if the drug was included in the CPOE system but was manually prescribed (OR = 3·3; 95% CI: 1·6-7·0, P < 0·001). WHAT IS NEW AND CONCLUSION: The presence of dosage PME in the manual prescriptions written within mixed prescription systems suggests that manual prescriptions should be totally avoided in neonatal units.

Antidepressant use and 10-year incident fracture risk: the population-based Canadian Multicentre Osteoporosis Study (CaMoS).

UNLABELLED: We used data from a large, prospective Canadian cohort to assess the association between selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors (SNRIs) and fracture. We found an increased risk of fractures in individuals who used SSRI or SNRI, even after controlling for multiple risk factors. INTRODUCTION: Previous studies have suggested an association between SSRIs and increasing risk of fragility fractures. However, the majority of these studies were not long-term analyses or were performed using administrative data and, thus, could not fully control for potential confounders. We sought to determine whether the use of SSRIs and SNRIs is associated with increased risk of fragility fracture, in adults aged 50 + . METHODS: We used data from the Canadian Multicentre Osteoporosis Study (CaMos), a prospective randomly selected population-based community cohort; our analyses focused on subjects aged 50+. Time to event methodology was used to assess the association between SSRI/SNRI use, modeled time-dependently, and fragility fracture. RESULTS: Among 6,645 subjects, 192 (2.9%) were using SSRIs or/and SNRIs at baseline. During the 10-year study period, 978 (14.7%) participants experienced at least one fragility fracture. In our main analysis, SSRI/SNRI use was associated with increased risk of fragility fracture (hazard ratio (HR), 1.88; 95% confidence intervals (CI), 1.48-2.39). After controlling for multiple risk factors, including Charlson score, previous falls, and bone mineral density hip and lumbar bone density, the adjusted HR for current SSRI/SNRI use remained elevated (HR, 1.68; 95% CI, 1.32-2.14). CONCLUSIONS: Our results lend additional support to an association between SSRI/SNRI use and fragility fractures. Given the high prevalence of antidepressants use, and the impact of fractures on health, our findings may have a significant clinical impact.

Opioid receptor mu 1 gene, fat intake and obesity in adolescence.

Dietary preference for fat may increase risk for obesity. It is a complex behavior regulated in part by the amygdala, a brain structure involved in reward processing and food behavior, and modulated by genetic factors. Here, we conducted a genome-wide association study (GWAS) to search for gene loci associated with dietary intake of fat, and we tested whether these loci are also associated with adiposity and amygdala volume. We studied 598 adolescents (12-18 years) recruited from the French-Canadian founder population and genotyped them with 530 011 single-nucleotide polymorphisms. Fat intake was assessed with a 24-hour food recall. Adiposity was examined with anthropometry and bioimpedance. Amygdala volume was measured by magnetic resonance imaging. GWAS identified a locus of fat intake in the µ-opioid receptor gene (OPRM1, rs2281617, P=5.2 × 10(-6)), which encodes a receptor expressed in the brain-reward system and shown previously to modulate fat preference in animals. The minor OPRM1 allele appeared to have a 'protective' effect: it was associated with lower fat intake (by 4%) and lower body-fat mass (by ∼2 kg, P=0.02). Consistent with the possible amygdala-mediated inhibition of fat preference, this allele was additionally associated with higher amygdala volume (by 69 mm(3), P=0.02) and, in the carriers of this allele, amygdala volume correlated inversely with fat intake (P=0.02). Finally, OPRM1 was associated with fat intake in an independent sample of 490 young adults. In summary, OPRM1 may modulate dietary intake of fat and hence risk for obesity, and this effect may be modulated by subtle variations in the amygdala volume.

Comparison of the ability of alternative birthweight and fetal weight standards to identify preterm newborns at increased risk of perinatal death.

OBJECTIVE: To compare prediction of perinatal deaths among preterm infants based on fetal weight standards versus a new subpopulation-based birthweight standard. DESIGN: Population-based cohort study. SETTING: France. POPULATION: A total of 9100 preterm singletons, born between 24 and 36 weeks of gestation in 2000-09, in Burgundy (France). METHODS: We first classified all newborns as either small for gestational age (SGA) or not, based on alternative fetal weight or birthweight standards, including a new birthweight standard that excludes infants born to mothers with disease related to the weight of a fetus. Based on discrepancies between the different classifications, we then divided the newborns into four groups, and compared their risks of stillbirth and in-hospital death, using a generalised linear model with relative risks (RR). MAIN OUTCOME MEASURES: Perinatal deaths, including, in separate analyses, stillbirths and in-hospital deaths. RESULTS: The preterm infants classified as SGA by our new subpopulation-based birthweight standard but not by the conventional birthweight standard had a significantly higher risk of both stillbirth (RR = 2.6; 95% confidence interval [95% CI] = 1.9-3.6) and in-hospital death (RR = 2.8; 95% CI = 1.8-4.5). In contrast, no risk increase was found for infants classified as SGA by the fetal standard only (RR = 1.1; 95% CI = 0.7-1.7 for stillbirths, and RR = 0.5; 95% CI = 0.3-1.3 for in-hospital deaths). CONCLUSIONS: Our subpopulation-based birthweight standard identified a subgroup of preterm newborns who have significantly increased risks of perinatal death but are not classified as SGA by the conventional birthweight standard. In contrast, the subgroup classified as SGA by the fetal standards only, but not by our subpopulation-based birthweight standard, had no increased risk of mortality, compared with non-SGA infants.

Congenital toxoplasma infection: monthly prenatal screening decreases transmission rate and improves clinical outcome at age 3 years.

BACKGROUND: Toxoplasma infection during pregnancy exposes the fetus to risks of congenital infection and sequelae that depend heavily on gestational age (GA) at time of infection. Accurate risk estimates by GA are necessary to counsel parents and improve clinical decisions. METHODS: We analyzed data from pregnant women diagnosed with acute Toxoplasma infection in Lyon (France) from 1987 to 2008 and assessed how the risks of congenital toxoplasmosis and of clinical signs at age 3 years vary depending on GA at the time of maternal infection. RESULTS: Among 2048 mother-infant pairs, 93.2% of mothers received prenatal treatment and 513 (24.7%) fetuses were infected. Because of a significant reduction in risk since 1992 when monthly screening was introduced (59.4% vs 46.6% at 26 GA weeks; P = .038), probabilities of infection were estimated on the basis of maternal infections diagnosed after mid-1992 (n = 1624). Probabilities of congenital infection were <10% for maternal infections before 12 weeks of gestation, rose to 20.0% at 19 weeks, and then continued increasing to 52.3% and almost 70% at 28 and 39 GA weeks, respectively. Because of a significant reduction in risk of clinical signs of congenital toxoplasmosis in infected children born from mothers diagnosed after 1995 when polymerase chain reaction testing on amniotic fluid was initiated (87/794 vs 46/1150; P = .012), probabilities of clinical signs at 3 years were estimated based on 1015 maternal infections diagnosed after 1995 including 207 infected children, with symptoms in 46 (22.2%). CONCLUSIONS: These analyses demonstrated that introduction of monthly prenatal screening and improvement in antenatal diagnosis were associated with a significant reduction in the rate of congenital infection and a better outcome at 3 years of age in infected children. Our updated estimates will improve individual management and counseling in areas where genotype II Toxoplasma is predominant.

Advantages and limitations of using national administrative data on obstetric blood transfusions to estimate the frequency of obstetric hemorrhages.

BACKGROUND: Obstetric hemorrhages are a frequent cause of maternal death all over the world, but are not routinely monitored. Health systems administrative databases could be used for this purpose, but data quality needs to be assessed. OBJECTIVES: Using blood transfusion data recorded in administrative databases to estimate the frequency of obstetric hemorrhages. Research design A population-based study. Subjects Validation sub-sample: all mothers who gave birth in a French region in 2006-07 (35 123 pregnancies). Main study: all mothers who gave birth in France in 2006-07 (1 629 537 pregnancies). METHOD: Linkage and comparison of administrative data on blood transfusions with data from the French blood agency ('gold standard'), and, based on this validation, the construction of a multivariable regression model to correct the number of pregnant women identified as having received a transfusion in the national administrative database. RESULTS: The blood transfusion rate observed in the gold standard was 7.12‰. The sensitivity of the administrative data was estimated at 66.3% and the positive predictive value at 91.3%. The estimated total number of pregnant women who received blood transfusions in France in 2006-07 was 10 941 (6.71‰). CONCLUSIONS: The administrative data, available in most countries, can be used to estimate the frequency of obstetric hemorrhages.

[Using routine information system data to assess maternal and perinatal care services in Mali and Senegal (QUARITE trial)]. / Utilisation des données recueillies en routine pour évaluer l'activité des maternités au Mali et au Sénégal (essai QUARITE).

BACKGROUND: In sub-Saharan Africa, problems of access to relevant and high-quality facility-based statistics hinder the assessment of safe motherhood programs. The objective of this study was to assess the quality of data collected in referral hospitals in Mali and Senegal after the routine information system (RIS) was strengthened. METHODS: This was a multicenter observational study conducted during the pre-intervention period of a randomized controlled trial (trial QUARITE). The RIS was strengthened based on technical, organizational and behavioral factors. We included all women who gave birth in the 46 referral hospitals from October 1, 2007 to October 30, 2008. The completeness, completion and accuracy rates were monitored every 3 months in each hospital. The cost of investment needed to strengthen the existing RIS was also determined. RESULTS: The mean completeness rate ranged from 94 to 97% depending on the study period. The completion and accuracy rates increased during the study period from 72% and 79% to 87% and 93%, respectively (significant differences). The average investment per hospital was less than 1% of state subsidies for public hospitals. CONCLUSION: Strengthening the existing information system has set up an economically and technologically appropriate system for monitoring maternal and perinatal health in Senegal and Mali. We encourage policy makers and researchers from countries with limited resources to invest in RIS to improve and monitor the performance of health systems.

Estimation of national colorectal-cancer incidence using claims databases.

Background. The aim of the study was to assess the accuracy of the colorectal-cancer incidence estimated from administrative data. Methods. We selected potential incident colorectal-cancer cases in 2004-2005 French administrative data, using two alternative algorithms. The first was based only on diagnostic and procedure codes, whereas the second considered the past history of the patient. Results of both methods were assessed against two corresponding local cancer registries, acting as "gold standards." We then constructed a multivariable regression model to estimate the corrected total number of incident colorectal-cancer cases from the whole national administrative database. Results. The first algorithm provided an estimated local incidence very close to that given by the regional registries (646 versus 645 incident cases) and had good sensitivity and positive predictive values (about 75% for both). The second algorithm overestimated the incidence by about 50% and had a poor positive predictive value of about 60%. The estimation of national incidence obtained by the first algorithm differed from that observed in 14 registries by only 2.34%. Conclusion. This study shows the usefulness of administrative databases for countries with no national cancer registry and suggests a method for correcting the estimates provided by these data.

Flexible modeling improves assessment of prognostic value of C-reactive protein in advanced non-small cell lung cancer.

BACKGROUND: C-reactive protein (CRP) is gaining credibility as a prognostic factor in different cancers. Cox's proportional hazard (PH) model is usually used to assess prognostic factors. However, this model imposes a priori assumptions, which are rarely tested, that (1) the hazard ratio associated with each prognostic factor remains constant across the follow-up (PH assumption) and (2) the relationship between a continuous predictor and the logarithm of the mortality hazard is linear (linearity assumption). METHODS: We tested these two assumptions of the Cox's PH model for CRP, using a flexible statistical model, while adjusting for other known prognostic factors, in a cohort of 269 patients newly diagnosed with non-small cell lung cancer (NSCLC). RESULTS: In the Cox's PH model, high CRP increased the risk of death (HR=1.11 per each doubling of CRP value, 95% CI: 1.03-1.20, P=0.008). However, both the PH assumption (P=0.033) and the linearity assumption (P=0.015) were rejected for CRP, measured at the initiation of chemotherapy, which kept its prognostic value for approximately 18 months. CONCLUSION: Our analysis shows that flexible modeling provides new insights regarding the value of CRP as a prognostic factor in NSCLC and that Cox's PH model underestimates early risks associated with high CRP.

Empirical study of the dependence of the results of multivariable flexible survival analyses on model selection strategy.

Flexible survival models, which avoid assumptions about hazards proportionality (PH) or linearity of continuous covariates effects, bring the issues of model selection to a new level of complexity. Each 'candidate covariate' requires inter-dependent decisions regarding (i) its inclusion in the model, and representation of its effects on the log hazard as (ii) either constant over time or time-dependent (TD) and, for continuous covariates, (iii) either loglinear or non-loglinear (NL). Moreover, 'optimal' decisions for one covariate depend on the decisions regarding others. Thus, some efficient model-building strategy is necessary.We carried out an empirical study of the impact of the model selection strategy on the estimates obtained in flexible multivariable survival analyses of prognostic factors for mortality in 273 gastric cancer patients. We used 10 different strategies to select alternative multivariable parametric as well as spline-based models, allowing flexible modeling of non-parametric (TD and/or NL) effects. We employed 5-fold cross-validation to compare the predictive ability of alternative models.All flexible models indicated significant non-linearity and changes over time in the effect of age at diagnosis. Conventional 'parametric' models suggested the lack of period effect, whereas more flexible strategies indicated a significant NL effect. Cross-validation confirmed that flexible models predicted better mortality. The resulting differences in the 'final model' selected by various strategies had also impact on the risk prediction for individual subjects.Overall, our analyses underline (a) the importance of accounting for significant non-parametric effects of covariates and (b) the need for developing accurate model selection strategies for flexible survival analyses.

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.

A comparison of damage accrual across different calendar periods in systemic lupus erythematosus patients.

Therapeutic approaches in systemic lupus erythematosus (SLE) have evolved over the last few decades, but their impact on prevention of organ damage is unknown. The objective of this study was to compare new cumulative damage in SLE patients across different calendar periods. Patients from a large SLE cohort were divided into two subcohorts; the first diagnosed and followed between 1978 and 1988 (cohort #1, n=100) and the second between 1989 and 1999 (cohort #2, n=51). Initial Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SLICC/ACR DI) scores, and changes in scores over the observation intervals, were compared for the two groups. Logistic regression estimated adjusted odds ratios (OR) comparing damage accrual between the two cohorts. Medication exposures were noted. Baseline characteristics were similar between the two groups. At first assessment, the adjusted OR for a SLICC/ACR DI score > or =1 was 1.79 (95% CI 0.82, 3.88) for cohort #1 versus cohort #2. At the end of the observation interval, the adjusted OR for a SLICC/ACR DI score > or =1 was 1.22 (0.58, 2.55) for cohort #1 versus cohort #2. The adjusted OR for accruing damage over the observation interval in cohort #1 versus cohort #2 was 0.94 (0.39, 2.44). Increased medication exposure was evident for cohort #2 compared to cohort #1. Despite increased therapeutic measures used for patients in more recent periods, our data do not establish a clear difference in damage accrual. This emphasizes the need for strategies to effectively treat lupus-specific manifestations, while minimizing side effects and comorbidities.