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41 result(s) for "Hummers, Laura K"
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Separated or joint models of repeated multivariate data to estimate individuals’ disease trajectories with application to scleroderma
Estimating a patient’s disease trajectory as defined by clinical measures is an essential task in medicine. Given multiple biomarkers, there is a practical choice of whether to estimate the joint distribution of all biomarkers in a single model or to model the univariate marginal distribution of each marker separately ignoring the covariance structure among measures. To fully utilize all trajectory-relevant information in multiple longitudinal markers, a joint model is required, but its complexity and computational burden may only be warranted when joint estimates of trajectories are substantially more efficient than separate estimates. This paper derives general expressions for the inefficiency of univariate or “separated\" estimates of population-average trajectories and individual’s random effects as compared to the fully efficient multivariate or “combined\" estimates. Then, in two settings: (1) a general bivariate case; and (2) our motivating clinical case study with 5 measures, we find that separated estimates of fixed effects are nearly fully efficient. However, joint estimates of random effects can be meaningfully more efficient for measures with substantial missing data when other strongly correlated measures are observed more frequently. This increased efficiency of the joint model derives more from joint shrinkage of random effects in multivariate space than from improved estimates of the subject-specific trajectories obtained when accounting for correlations in measurements. These findings have application to a diverse array of chronic diseases where biomarkers’ trajectories guide clinical decisions.
Impact of lung function decline on time to hospitalisation events in systemic sclerosis-associated interstitial lung disease (SSc-ILD): a joint model analysis
Background Interstitial lung disease (ILD) is a common organ manifestation in systemic sclerosis (SSc) and is the leading cause of death in patients with SSc. A decline in forced vital capacity (FVC) is an indicator of ILD progression and is associated with mortality in patients with SSc-associated ILD (SSc-ILD). However, the relationship between FVC decline and hospitalisation events in patients with SSc-ILD is largely unknown. The objective of this post hoc analysis was to investigate the relationship between FVC decline and clinically important hospitalisation endpoints. Methods We used data from SENSCIS®, a phase III trial investigating the efficacy and safety of nintedanib in patients with SSc-ILD. Joint models for longitudinal and time-to-event data were used to assess the association between rate of decline in FVC% predicted and hospitalisation-related endpoints (including time to first all-cause hospitalisation or death; time to first SSc-related hospitalisation or death; and time to first admission to an emergency room [ER] or admission to hospital followed by admission to intensive care unit [ICU] or death) during the treatment period, over 52 weeks in patients with SSc-ILD. Results There was a statistically significant association between FVC decline and the risk of all-cause ( n = 78) and SSc-related ( n = 42) hospitalisations or death (both P < 0.0001). A decrease of 3% in FVC corresponded to a 1.43-fold increase in risk of all-cause hospitalisation or death (95% confidence interval [CI] 1.24, 1.65) and a 1.48-fold increase in risk of SSc-related hospitalisation or death (95% CI 1.23, 1.77). No statistically significant association was observed between FVC decline and admission to ER or to hospital followed by admission to ICU or death ( n = 75; P = 0.15). The estimated slope difference for nintedanib versus placebo in the longitudinal sub-model was consistent with the primary analysis in SENSCIS®. Conclusions The association of lung function decline with an increased risk of hospitalisation suggests that slowing FVC decline in patients with SSc-ILD may prevent hospitalisations. Our findings also provide evidence that FVC decline may serve as a surrogate endpoint for clinically relevant hospitalisation-associated endpoints. Trial registration ClinicalTrials.gov NCT02597933 . Registered on 8 October 2015.
Hemodynamic Predictors of Survival in Scleroderma-related Pulmonary Arterial Hypertension
Pulmonary arterial hypertension (PAH) related to systemic sclerosis (SSc) has a poorer prognosis compared with other forms of PAH for reasons that remain unexplained. To identify risk factors of mortality in a well-characterized cohort of patients with PAH related to systemic sclerosis (SSc-PAH). Seventy-six consecutive patients with SSc (64 women and 12 men; mean age 61 +/- 11 yr) were diagnosed with PAH by heart catheterization in a single center, starting in January 2000, and followed over time. Kaplan-Meier estimates were calculated and mortality risk factors were analyzed. Forty (53%) patients were in World Health Organization functional class III or IV. Mean pulmonary artery pressure was 41 +/- 11 mm Hg, pulmonary vascular resistance (PVR) was 8.6 +/- 5.6 Wood units, and cardiac index was 2.4 +/- 0.7 L/min/m(2). Median follow-up time was 36 months, with 42 deaths observed. Survival estimates were 85%, 72%, 67%, 50%, and 36% at 1, 2, 3, 4, and 5 years, respectively. Multivariate analysis identified PVR (hazard ratio [HR], 1.10; 95% confidence interval [CI], 1.03-1.18; P < 0.01), stroke volume index (HR, 0.94; 95% CI, 0.89-0.99; P = 0.02), and pulmonary arterial capacitance (HR, 0.43; 95% CI, 0.20-0.91; P = 0.03) as strong predictors of survival. An estimated glomerular filtration rate less than 60 ml/min/1.73 m(2) portended a threefold risk of mortality. Our results suggest that specific components of right ventricular dysfunction and renal impairment contribute to increased mortality in SSc-PAH. Understanding the mechanisms of right ventricular dysfunction in response to increased afterload should lead to improved targeted therapy in these patients.
Targeting of dermal myofibroblasts through death receptor 5 arrests fibrosis in mouse models of scleroderma
Scleroderma is an autoimmune rheumatic disorder accompanied by severe fibrosis in skin and other internal organs. During scleroderma progression, resident fibroblasts undergo activation and convert to α-smooth muscle actin (α-SMA) expressing myofibroblasts (MFBs) with increased capacity to synthesize collagens and fibrogenic components. Accordingly, MFBs are a major therapeutic target for fibrosis in scleroderma and treatment with blocking MFBs could produce anti-fibrotic effects. TLY012 is an engineered human TNF-related apoptosis-inducing ligand (TRAIL) which induces selective apoptosis in transformed cells expressing its cognate death receptors (DRs). Here we report that TLY012 selectively blocks activation of dermal fibroblasts and induces DR-mediated apoptosis in α-SMA +  MFBs through upregulated DR5 during its activation. In vivo, TLY012 reverses established skin fibrosis to near-normal skin architecture in mouse models of scleroderma. Thus, the TRAIL pathway plays a critical role in tissue remodeling and targeting upregulated DR5 in α-SMA + MFBs is a viable therapy for fibrosis in scleroderma. Dermal myofibroblasts are responsible for fibrosis development in scleroderma. Here the authors show that a bioengineered recombinant human TRAIL ligand reverses established fibrosis in mouse models of scleroderma by targeting the death receptor 5 and inducing apoptosis of myofibroblasts.
Predicting clinical events using Bayesian multivariate linear mixed models with application to scleroderma
Background Scleroderma is a serious chronic autoimmune disease in which a patient’s disease state manifests in several irregularly spaced longitudinal measures of lung, heart, skin, and other organ systems. Threshold crossings of pulmonary and cardiac measures indicate potentially life-threatening key clinical events including interstitial lung disease (ILD), cardiomyopathy, and pulmonary hypertension (PH). The statistical challenge is to accurately and precisely predict these events by using all of the clinical history for the patient at hand and for a reference population of patients. Methods We use a Bayesian mixed model approach to simultaneously characterize each individual’s future trajectories for several biomarkers. We estimate this model using a large population of patients from the Johns Hopkins Scleroderma Center Research Registry. The joint probabilities of critical lung and heart events are then calculated as a byproduct of the mixed model. Results The performance of this approach is substantially better than standard, more common alternatives. In order to predict an individual’s risks in a clinical setting, we also develop a cross-validated, sequential prediction (CVSP) algorithm. As additional data are observed during a patient’s visit, the algorithm sequentially produces updated predictions for the future longitudinal trajectories and for ILD, cardiomyopathy, and PH. The updated prediction distributions with little additional computing, for example within an electronic health record (EHR). Conclusions This method that generates real-time personalized risk estimates has been implemented within the electronic health record system for clinical testing. To our knowledge, this work represents the first approach to compute personalized risk estimates for multiple scleroderma complications.
Long-term experience of mycophenolate mofetil for treatment of diffuse cutaneous systemic sclerosis
Background Immunosuppressive therapy may potentially alter the natural disease course of scleroderma. There have been reports of using mycophenolate mofetil (MMF) for the treatment of scleroderma skin disease. Objective To analyse the experience of using MMF for the treatment of active diffuse cutaneous scleroderma. Methods The authors compared the change in mean modified Rodnan skin scores (mRSS) in an MMF cohort at baseline with scores at 3, 6, 9 and 12 months and with those of historical controls from a pooled analysis of three multicentre randomised clinical trials of recombinant human relaxin, d-penicillamine and oral bovine type I collagen. Results Improvement in mRSS after treatment with MMF compared with baseline was seen as early as 3 months and continued through the 12-month follow-up. The mRSS of the MMF cohort was not different from that of the historical controls at 6 months (MMF −3.05±7.4 vs relaxin −4.83±6.99, p=0.059), but was significantly lower at 12 months (MMF −7.59±10.1 vs d-penicillamine −2.47±8.6, p<0.001; collagen −3.4±7.12, p=0.002). General and muscle severity scores and quality of life measures also improved compared with baseline. Pulmonary function remained stable. Conclusions MMF may benefit skin disease in patients with diffuse scleroderma, but prospective studies are required to determine its role.
Abnormal Esophageal Scintigraphy Associates With a Distinct Clinical Phenotype in Patients With Systemic Sclerosis
Objective In systemic sclerosis (SSc), absent contractility (AC) rather than ineffective esophageal motility on manometry is associated with a severe esophageal and extraintestinal phenotype. We sought to determine whether slow esophageal transit on scintigraphy associates with a comparable clinical phenotype to that of AC on manometry, as scintigraphy may serve as a noninvasive approach to risk‐stratify patients with SSc. Methods Clinical, demographic, and serologic features were compared between patients with and without delayed esophageal transit on scintigraphy. University of California Los Angeles Scleroderma Clinical Trials Consortium Gastrointestinal Tract (GIT) 2.0 scores measured GI symptoms, Medsger scores measured physician‐assessed SSc disease severity, and the Composite Autonomic Symptom Score 31 survey evaluated dysautonomia symptoms. Results Of 131 patients, 79 (60%) had delayed esophageal transit by scintigraphy. Patients with delayed esophageal transit were more likely to have diffuse SSc (24 [32%] vs 11 [22%]; P = 0.024), severe lung involvement (22 [41%] vs 7 [19%]; P = 0.034), severe Raynaud (36 [47%] vs 15 [31%]; P = 0.063), and a higher median (interquartile range [IQR]) diarrhea GIT score (0.5 [IQR 0–1] vs 0 [IQR 0–1]; P = 0.050). Lower diffusing capacity of the lungs for carbon monoxide values correlated with a higher esophageal transit time (ρ = −0.32; P = 0.014). After adjusting for disease duration, delayed esophageal transit was significantly associated with severe Medsger lung scores, severe Raynaud phenomenon, and higher modified Rodnan skin scores. Conclusion Patients with delayed esophageal transit by scintigraphy have a more severe SSc phenotype, similar to patients with AC, on esophageal manometry. Further studies should validate esophageal scintigraphy as a tool to identify patients with SSc with AC who may develop specific GI and extraintestinal complications.
Autoantibodies and scleroderma phenotype define subgroups at high-risk and low-risk for cancer
ObjectivesRecent studies demonstrate autoantibodies are powerful tools to interrogate molecular events linking cancer and the development of autoimmunity in scleroderma. Investigating cancer risk in these biologically relevant subsets may provide an opportunity to develop personalised cancer screening guidelines. In this study, we examined cancer risk in distinct serologic and phenotypic scleroderma subsets and compared estimates with the general population.MethodsPatients in the Johns Hopkins Scleroderma Center observational cohort were studied. Overall and site-specific cancer incidence was calculated in distinct autoantibody and scleroderma phenotypic subsets, and compared with the Surveillance, Epidemiology and End Results registry, a representative sample of the US population.Results2383 patients with scleroderma contributing 37 686 person-years were studied. 205 patients (8.6%) had a diagnosis of cancer. Within 3 years of scleroderma onset, cancer risk was increased in patients with RNA polymerase III autoantibodies (antipol; standardised incidence ratio (SIR) 2.84, 95% CI 1.89 to 4.10) and those lacking centromere, topoisomerase-1 and pol antibodies (SIR 1.83, 95% CI 1.10 to 2.86). Among antipol-positive patients, cancer-specific risk may vary by scleroderma subtype; those with diffuse scleroderma had an increased breast cancer risk, whereas those with limited scleroderma had high lung cancer risk. In contrast, patients with anticentromere antibodies had a lower risk of cancer during follow-up (SIR 0.59, 95% CI 0.44 to 0.76).ConclusionsAutoantibody specificity and disease subtype are biologically meaningful filters that may inform cancer risk stratification in patients with scleroderma. Future research testing the value of targeted cancer screening strategies in patients with scleroderma is needed.
Computed Tomography of the Chest to Screen for Interstitial Lung Disease in Patients With Systemic Sclerosis at Expert Scleroderma Centers in the United States
Objective Although a high‐resolution computed tomography (HRCT) scan of the chest is the gold standard test for the detection of interstitial lung disease (ILD), there is no consensus among rheumatologists regarding the use of HRCT to screen for ILD in their patients with systemic sclerosis (SSc). The aims of this study were to describe the HRCT ordering practices at SSc centers in the United States and to determine which patient characteristics are associated with HRCT performance. Methods We performed a prospective cohort study of patients with SSc enrolled in the US‐based Collaborative National Quality and Efficacy Registry (CONQUER). We performed univariate logistic regression followed by multivariable logistic regression to determine which patient characteristics were associated with HRCT performance. Results Of the 356 patients with SSc enrolled in CONQUER, 286 (80.3%) underwent HRCT at some point during their disease course. On multivariable analyses, missing total lung capacity percent predicted (odds ratio [OR] 3.26, 95% confidence interval [CI]: 1.53‐7.41, P = 0.007) was positively associated with ever having undergone HRCT, whereas a positive anti‐centromere antibody (OR 0.27, 95% CI: 0.12‐0.61, P = 0.008) and missing forced vital capacity percent predicted (OR 0.29, 95% CI: 0.10‐0.80, P = 0.005) were negatively associated with ever having undergone HRCT. There was a trend toward a positive association between crackles on pulmonary exam and ever having undergone HRCT (OR 2.28, 95% CI: 0.97‐6.05, P = 0.058), although this relationship did not reach statistical significance. Conclusion The majority of patients with SSc enrolled in CONQUER underwent HRCT. A positive anti‐centromere antibody was the key clinical variable inversely associated with performance of HRCT.
Systemic sclerosis with associated interstitial lung disease: management considerations and future directions
Systemic sclerosis (SSc), also referred to as scleroderma, is a rare autoimmune disease associated with vasculopathy, inflammation, and fibrosis of the skin and/or internal organs. Interstitial lung disease (ILD) is a frequent complication and is the leading cause of death in patients with SSc. Although economic data are limited, available data suggest that SSc-ILD is associated with significant cost implications. Treatment of SSc-ILD has historically been with immunosuppressive agents. In 2019, however, the treatment landscape expanded with the FDA approval of the tyrosine kinase inhibitor nintedanib. A lack of codified treatment guidelines for patients with SSc-ILD creates significant challenges in improving outcomes at the patient level and, more generally, in reducing disease burden to the health care system. As the treatment landscape continues to evolve, it is likely that to reduce lung volume loss in patients, a combination of immunosuppressive and antifibrotic approaches will need to be used. Additionally, a greater emphasis on risk-stratification strategies may allow for more efficient follow-up, monitoring, and assessment of treatment response.