African-American race and mortality in interstitial lung disease: a multicentre propensity-matched analysis.

We studied whether African-American race is associated with younger age and decreased survival time at diagnosis of interstitial lung disease (ILD).We performed a multicentre, propensity score-matched analysis of patients with an ILD diagnosis followed at five US hospitals between 2006 and 2016. African-Americans were matched with patients of other races based on a time-dependent propensity score calculated from multiple patient, physiological, diagnostic and hospital characteristics. Multivariable logistic regression models were used. All-cause mortality and hospitalisations were compared between race-stratified patient cohorts with ILD, and sensitivity analyses were performed.The study included 1640 patients with ILD, 13% of whom were African-American, followed over 5041 person-years. When compared with patients of other races, African-Americans with ILD were younger at diagnosis (56 years versus 67 years), but in the propensity-matched analyses had greater survival (hazard ratio 0.46, 95% CI 0.28-0.77; p=0.003) despite similar risk of respiratory hospitalisations (relative risk 1.04, 95% CI 0.83-1.31; p=0.709), and similar GAP-ILD (gender-age-physiology-ILD) scores at study entry. Sensitivity analyses in a separate cohort of 9503 patients with code-based ILD diagnosis demonstrated a similar association of baseline demographic characteristics with all-cause mortality.We conclude that African-Americans demonstrate a unique phenotype associated with younger age at ILD diagnosis and perhaps longer survival time.

N-acetylcysteine exposure is associated with improved survival in anti-nuclear antibody seropositive patients with usual interstitial pneumonia.

BACKGROUND: Mortality is similarly high among individuals with usual interstitial pneumonia (UIP) due to idiopathic pulmonary fibrosis (IPF) and interstitial pneumonia with autoimmune features (IPAF). Circulating anti-nuclear antibodies (ANA) are commonly found in this patient population, suggesting possible aberrant immune activation. Because an environment of oxidative stress can result from immunologic activation, we hypothesized that ANA positive patients with UIP would have improved outcome when exposed to the antioxidant N-acetylcysteine (NAC) compared to ANA negative patients. METHODS: A single center, retrospective cohort analysis was performed. Patients with UIP due to IPF and IPAF were stratified according to ANA status to and NAC exposure. Transplant-free survival (TFS) was assessed using the Kaplan-Meier estimator and multivariable Cox regression adjusted for diagnosis, gender/age/physiology score, immunosuppressant exposure and anti-fibrotic exposure. RESULTS: Of 293 individuals with UIP due to IPF (74%) or IPAF (26%), NAC exposure was documented in 58 (19.8%). Among NAC exposed individuals, 33 (56.9%) were ANA seropositive and 25 (43.1%) were seronegative. NAC exposure was associated with improved TFS survival among ANA seropositive individuals in unadjusted analysis (plogrank = 0.02) and after multi-variable adjustment (HR 0.51, 95% CI 0.30-0.87; p = 0.01). There was no association between NAC exposure and TFS in ANA seronegative individuals (HR 1.26, 95% CI 0.69-2.32; p = 0.45). Formal interaction testing confirmed NAC*ANA interaction (p = 0.04) and sensitivity analysis demonstrated an increasing effect size associated with NAC therapy as ANA titer increased. Among patients with available genetic data, a marginally higher proportion of ANA positive patients (p = 0.08) carried the rs3750920 (TOLLIP) genotype previously shown to predict favorable outcome in NAC exposed patients. CONCLUSION: NAC exposure is associated with improved transplant-free survival ANA positive patients with UIP. These findings support the prospective collection of ANA data in in future NAC clinical trials performed in patients with UIP.

Phenotypic Clusters Predict Outcomes in a Longitudinal Interstitial Lung Disease Cohort.

BACKGROUND: The current interstitial lung disease (ILD) classification has overlapping clinical presentations and outcomes. Cluster analysis modeling is a valuable tool in identifying distinct clinical phenotypes in heterogeneous diseases. However, this approach has yet to be implemented in ILD. METHODS: Using cluster analysis, novel ILD phenotypes were identified among subjects from a longitudinal ILD cohort, and outcomes were stratified according to phenotypic clusters compared with subgroups according to current American Thoracic Society/European Respiratory Society ILD classification criteria. RESULTS: Among subjects with complete data for baseline variables (N = 770), four clusters were identified. Cluster 1 (ie, younger white obese female subjects) had the highest baseline FVC and diffusion capacity of the lung for carbon monoxide (Dlco). Cluster 2 (ie, younger African-American female subjects with elevated antinuclear antibody titers) had the lowest baseline FVC. Cluster 3 (ie, elderly white male smokers with coexistent emphysema) had intermediate FVC and Dlco. Cluster 4 (ie, elderly white male smokers with severe honeycombing) had the lowest baseline Dlco. Compared with classification according to ILD subgroup, stratification according to phenotypic clusters was associated with significant differences in monthly FVC decline (Cluster 4, -0.30% vs Cluster 2, 0.01%; P < .0001). Stratification by using clusters also independently predicted progression-free survival (P < .001) and transplant-free survival (P < .001). CONCLUSIONS: Among adults with diverse chronic ILDs, cluster analysis using baseline characteristics identified four distinct clinical phenotypes that might better predict meaningful clinical outcomes than current ILD diagnostic criteria.

Autoimmune Hypothyroidism As a Predictor of Mortality in Chronic Hypersensitivity Pneumonitis.

BACKGROUND: Chronic hypersensitivity pneumonitis (CHP) is a fibrotic parenchymal lung disease that occurs when inhalation of environmental antigens leads to immune dysregulation. Autoimmune features have recently been identified as potentially important among patients with CHP. However, the relationship between hypothyroidism (HT) and CHP is unknown. In this study, we investigate the prevalence and impact of HT among patients with CHP. METHODS: We conducted a retrospective, case-control analysis. We identified 121 patients at the University of Chicago Interstitial Lung Disease Center with a multidisciplinary diagnosis of CHP. These patients were matched 3:1 according to age, sex, and race to 363 control subjects with asthma from 2006 to 2015. We analyzed demographics, clinical characteristics, and survival between both groups and assessed the relationship of HT with CHP. Survival analysis was performed using Cox proportional hazards modeling. RESULTS: Patients with CHP had higher prevalence of HT (25.6%, n = 31) compared to controls (10.7%, n = 39; OR, 2.86; 95% CI, 1.62-4.99; P < 0.0001). Compared to CHP alone, patients with CHP/HT were more likely to be female (80.6 vs 51.1%, P = 0.004), have increased incidence of autoimmune disease (19.4 vs 3.3%, P = 0.009), antinuclear antibody seropositivity (80.6 vs 57.0%, P = 0.019), and higher TSH levels (4.0 vs 1.9 mIU/L, P < 0.0001). HT was a significant independent predictor of mortality among CHP patients with seropositive ANA (HR, 3.39; 95% CI, 1.31-8.80; P = 0.012). CONCLUSION: HT is common in patients with CHP and may carry prognostic significance in patients with features of autoimmunity. Further research exploring common pathogenic pathways between autoimmune HT and CHP may illuminate the association of HT with survival.

Outcomes of immunosuppressive therapy in chronic hypersensitivity pneumonitis.

In chronic hypersensitivity pneumonitis (CHP), lack of improvement or declining lung function may prompt use of immunosuppressive therapy. We hypothesised that use of azathioprine or mycophenolate mofetil with prednisone reduces adverse events and lung function decline, and improves transplant-free survival. Patients with CHP were identified. Demographic features, pulmonary function tests, incidence of treatment-emergent adverse events (TEAEs) and transplant-free survival were characterised, compared and analysed between patients stratified by immunosuppressive therapy. A multicentre comparison was performed across four independent tertiary medical centres. Among 131 CHP patients at the University of Chicago medical centre (Chicago, IL, USA), 93 (71%) received immunosuppressive therapy, and had worse baseline forced vital capacity (FVC) and diffusing capacity, and increased mortality compared with those who did not. Compared to patients treated with prednisone alone, TEAEs were 54% less frequent with azathioprine therapy (p=0.04) and 66% less frequent with mycophenolate mofetil (p=0.002). FVC decline and survival were similar between treatment groups. Analyses of datasets from four external tertiary medical centres confirmed these findings. CHP patients who did not receive immunosuppressive therapy had better survival than those who did. Use of mycophenolate mofetil or azathioprine was associated with a decreased incidence of TEAEs, and no difference in lung function decline or survival when compared with prednisone alone. Early transition to mycophenolate mofetil or azathioprine may be an appropriate therapeutic approach in CHP, but more studies are needed.

Azathioprine response in patients with fibrotic connective tissue disease-associated interstitial lung disease.

BACKGROUND: Azathioprine is a commonly prescribed therapy for connective tissue disease-associated interstitial lung disease (CTD-ILD). Combination therapy that included azathioprine was recently shown to increase the risk of death and hospitalization in patients with idiopathic pulmonary fibrosis. Whether azathioprine increases the risk of adverse outcomes in patients with fibrotic CTD-ILD, including those with CTD-associated usual interstitial pneumonia (UIP), remains unknown. METHODS: A retrospective cohort analysis was performed to determine the combined incidence rate of death, transplant and respiratory hospitalization associated with azathioprine exposure. A fibrotic CTD-ILD cohort treated with mycophenolate mofetil served as a comparator group. Incidence rates were compared with an incidence rate ratio (IRR) generated by negative binomial regression. Longitudinal pulmonary function response was then assessed using mixed effects linear regression models. RESULTS: Fifty-four patients were treated with azathioprine and forty-three with mycophenolate. Medication discontinuation due to non-respiratory side effects occurred in 27% and 5% of the azathioprine and mycophenolate cohorts, respectively. The combined incidence rate of adverse outcomes was 0.015 and 0.013 for azathioprine and mycophenolate, respectively (IRR 1.23; 95% CI 0.49-3.12; p = 0.66). Similar incidence rates were observed among those with CTD-UIP (IRR 0.83; 95% CI 0.21-3.31; p = 0.79). Both groups demonstrated pulmonary function stability over time, with the azathioprine group demonstrating a marginal improvement. CONCLUSIONS: A significant minority of patients could not tolerate azathioprine due to non-respiratory side effects. Of those who did tolerate azathioprine, a similar incidence of adverse outcomes was observed as those treated with mycophenolate. Both therapies were associated with stability in pulmonary function.