A Bayesian semiparametric Markov regression model for juvenile dermatomyositis.

Juvenile dermatomyositis (JDM) is a rare autoimmune disease that may lead to serious complications, even to death. We develop a 2-state Markov regression model in a Bayesian framework to characterise disease progression in JDM over time and gain a better understanding of the factors influencing disease risk. The transition probabilities between disease and remission state (and vice versa) are a function of time-homogeneous and time-varying covariates. These latter types of covariates are introduced in the model through a latent health state function, which describes patient-specific health over time and accounts for variability among patients. We assume a nonparametric prior based on the Dirichlet process to model the health state function and the baseline transition intensities between disease and remission state and vice versa. The Dirichlet process induces a clustering of the patients in homogeneous risk groups. To highlight clinical variables that most affect the transition probabilities, we perform variable selection using spike and slab prior distributions. Posterior inference is performed through Markov chain Monte Carlo methods. Data were made available from the UK JDM Cohort and Biomarker Study and Repository, hosted at the UCL Institute of Child Health.

ß-Blocker Therapy and Clinical Outcomes in Patients with Moderate Chronic Obstructive Pulmonary Disease and Heightened Cardiovascular Risk. An Observational Substudy of SUMMIT.

RATIONALE: Cardiovascular disease is a common comorbidity in patients with chronic obstructive pulmonary disease. Although ß-blockers can be used safely in patients with chronic obstructive pulmonary disease, concerns remain regarding safety and efficacy interactions in patients using concomitant inhaled long-acting ß-agonists. OBJECTIVES: To compare the differential effects of long-acting ß-agonist or inhaled corticosteroid use on clinical outcomes in patients with heightened cardiovascular risk treated and not treated with ß-blockers. METHODS: We examined data from 16,485 participants in the SUMMIT study (Study to Understand Mortality and Morbidity in COPD) who were randomized to once-daily inhaled fluticasone furoate, vilanterol, fluticasone furoate/vilanterol combination, or placebo and examined the associations between treatment allocation and lung function, chronic obstructive pulmonary disease exacerbations, cardiovascular events, and all-cause mortality, stratified by baseline ß-blocker therapy. RESULTS: Baseline ß-blocker therapy was used by 31% (n = 5,159) of SUMMIT participants. There was no evidence of an interaction between baseline ß-blocker therapy and the association between inhaled treatments and forced expiratory volume in 1 second at 3 months (P = 0.27), 6 months (P = 0.14), or 12 months (P = 0.33). The placebo-adjusted mean differences in post-bronchodilator forced expiratory volume in 1 second at 3 months in the vilanterol-alone group were 58 ml (95% confidence interval, 38-78) in those receiving baseline ß-blocker therapy and 51 ml (95% confidence interval, 38-65) in those not receiving baseline ß-blocker therapy. The placebo-adjusted mean differences in post-bronchodilator forced expiratory volume in 1 second at 3 months in the combination fluticasone furoate/vilanterol group were 85 ml (95% confidence interval, 65-105) in those receiving baseline ß-blocker therapy and 68 ml (95% confidence interval, 54-82) in those not receiving baseline ß-blocker therapy. Overall, there was no evidence of interaction by randomized treatment, including vilanterol alone or in combination with fluticasone furoate, for chronic obstructive pulmonary disease exacerbations (P = 0.18), cardiovascular composite events (P = 0.33), and all-cause mortality (P = 0.41). CONCLUSIONS: There is no evidence to suggest that baseline ß-blocker therapy reduces the respiratory benefits or increases the cardiovascular risk of inhaled long-acting ß-agonists in patients with chronic obstructive pulmonary disease and heightened cardiovascular risk. Clinical trial registered with www.clinicaltrials.gov (NCT01313676).

Fluticasone Furoate, Vilanterol, and Lung Function Decline in Patients with Moderate Chronic Obstructive Pulmonary Disease and Heightened Cardiovascular Risk.

RATIONALE: Many patients with chronic obstructive pulmonary disease (COPD) have an accelerated loss of lung function. It is unclear whether drug treatment can modify this in patients with moderately severe disease. OBJECTIVES: In a prespecified analysis of the key secondary outcome in SUMMIT (Study to Understand Mortality and Morbidity), we investigated whether the inhaled corticosteroid fluticasone furoate (FF; 100 µg), the long-acting ß-agonist vilanterol (VI; 25 µg), or their combination (FF/VI) modified the rate of decline in FEV1 compared with placebo. We also investigated how baseline covariates affected this decline. METHODS: Spirometry was measured every 12 weeks in this event-driven, randomized, placebo-controlled trial of 16,485 patients with moderate COPD and heightened cardiovascular risk. An average of seven spirometric assessments per subject among the 15,457 patients with at least one on-treatment measurement were used in the analysis of rate of FEV1 decline. All statistical comparisons are considered nominal. MEASUREMENTS AND MAIN RESULTS: The adjusted rates of FEV1 decline were -46 ml/yr (-3.0% of baseline) with placebo, -47 ml/yr (-3.1%) with VI, -38 ml/yr (-2.5%) with FF, and -38 ml/yr (-2.3%) with FF/VI. FF-containing regimens had lower rates of decline than placebo (P < 0.03), and FF/VI had a lower rate of decline than VI alone (P < 0.005). The FEV1 decline was faster in current smokers, those with a lower body mass index, males, and patients with established cardiovascular disease. CONCLUSIONS: In patients with moderate COPD and heightened cardiovascular risk, FF alone or in combination with VI appears to reduce the rate of FEV1 decline. Clinical trial registered with www.clinicaltrials.gov (NCT01313676).

Comparison of the Utility and Validity of Three Scoring Tools to Measure Skin Involvement in Patients With Juvenile Dermatomyositis.

OBJECTIVE: To compare the abbreviated Cutaneous Assessment Tool (CAT), Disease Activity Score (DAS), and Myositis Intention to Treat Activity Index (MITAX) and correlate them with the physician's 10-cm skin visual analog scale (VAS) in order to define which tool best assesses skin disease in patients with juvenile dermatomyositis. METHODS: A total of 71 patients recruited to the UK Juvenile Dermatomyositis Cohort and Biomarker Study were included and assessed for skin disease using the CAT, DAS, MITAX, and skin VAS. The Childhood Myositis Assessment Scale (CMAS), manual muscle testing of 8 groups (MMT8), muscle enzymes, inflammatory markers, and physician's global VAS were recorded. Relationships were evaluated using Spearman's correlations and predictors with linear regression. Interrater reliability was assessed using intraclass correlation coefficients. RESULTS: All 3 tools showed correlation with the physician's global VAS and skin VAS, with DAS skin showing the strongest correlation with skin VAS. DAS skin and CAT activity were inversely correlated with CMAS and MMT8, but these correlations were moderate. No correlations were found between the skin tools and inflammatory markers or muscle enzymes. DAS skin and CAT were the quickest to complete (mean ± SD 0.68 ± 0.1 minutes and 0.63 ± 0.1 minutes, respectively). CONCLUSION: The 3 skin tools were quick and easy to use. The DAS skin correlated best with the skin VAS. The addition of CAT in a bivariate model containing the physician's global VAS was a statistically significant estimator of skin VAS score. We propose that there is scope for a new skin tool to be devised and tested, which takes into account the strengths of the 3 existing tools.