Robert Suruki

Cluster analysis and characterization of response to mepolizumab. A step closer to personalized medicine for patients with severe asthma.

RATIONALE Detailed characterization of asthma phenotypes is essential for identification of responder populations to allow directed personalized medical intervention. OBJECTIVES The aim of this study was to identify distinctive patient characteristics within subgroups of a well-characterized severe asthma population at risk for exacerbations and to determine the treatment response within each subgroup. METHODS A supervised cluster analysis with recursive partitioning approach was applied to data from the Dose Ranging Efficacy And safety with Mepolizumab (DREAM) study to identify characteristics that maximized the differences across subgroups. Exacerbation rate ratios were calculated for each cluster comparing mepolizumab versus placebo. MEASUREMENTS AND MAIN RESULTS Three predictors were identified in four primary clusters: blood eosinophils, airway reversibility, and body mass index. The reduction in exacerbations was significantly greater in patients who received mepolizumab (clusters 2, 3, and 4) with raised eosinophils (responder population). Cluster 2 with low airway reversibility (mean, 11%) had a 53% reduction in exacerbations. These patients more frequently reported sinusitis and nasal polyposis. Those with higher airway reversibility (mean, 28%) were further split by body mass index. The nonobese versus obese (clusters 3 and 4) had a 35 and 67% reduction in exacerbations, respectively. Cluster 4 also had patients with more comorbidities, including hypertension, weight gain, and anxiety. CONCLUSIONS Using supervised cluster analysis helped identify specific patient characteristics related to disease and therapeutic response. Patients with eosinophilic inflammation received significant therapeutic benefit with mepolizumab, and responses differed within clusters. Clinical trial registered with www.clinicaltrials.gov (NCT01000506).

A Cohort Study of the Impact of Tooth Loss and Periodontal Disease on Respiratory Events among COPD Subjects: Modulatory Role of Systemic Biomarkers of Inflammation

Background In COPD patients, fatal and non-fatal respiratory-related events are influenced by age, severity of respiratory disease, and comorbidities. Objectives Analyze the effects of edentulism, periodontal disease and systemic biomarkers of inflammation on the occurrence of serious fatal and non-fatal respiratory-related events among subjects with COPD. Methods Cases were identified from Dental Atherosclerosis Risk in Communities study. Edentulism was defined as study participants without any natural teeth or implants. Participants with one or more natural teeth (comprising 11,378 subjects) were studied as dentate subjects. Periodontal disease status among dentate individuals was determined using the consensus definitions published by the joint Center for Disease Control/American Association of Periodontology working group). Adjusted Hazard Models are developed to evaluate the relationship between edentulism/periodontal disease and COPD Related Events. Models were then stratified by GOLD Stage I, II and III/IV. Serum biomarkers were also evaluated to explore the effect of systemic inflammation. Results A statistically significant association was found between oral health status and COPD-related events, even adjusting for conditions such as hypertension, smoking and diabetes. Edentulous individuals who had been diagnosed with COPD had a higher incidence and were at greater risk of having a COPD related event (hospitalization and death) than individuals who had teeth and whose mouths had healthy periodontal status. However, being edentulous did not convey excess risk for COPD-related events for those study participants who were classified as GOLD III/IV at baseline. Finally, we showed that individuals who had levels of serum IL-6 in the highest two quartiles were at even higher risk for COPD-related events. Conclusions These findings suggest that the risk for COPD-related events after adjusting for potential confounders may be attributable to both edentulism and elevated serum IL-6 levels.

Association of CHI3L1 in African-Americans with Prior History of Asthma Exacerbations and Stress

Rationale. Asthma exacerbations are influenced by multiple factors including environmental exposures, psychosocial interactions, and genetic variations. Aim. To better understand the correlation between clinical, physiologic, genetic, and psychological dimensions in asthma phenotypes and exacerbations. Methods. Supervised cluster analysis of a previously conducted clinical trial of asthma was used to identify subpopulations with differing exacerbation rates in an African-American study population (n = 475). The clusters were characterized by their clinical characteristics and genetic variations. The genetic analysis (n = 322) compared subgroups across 40 different polymorphisms of 10 genes associated with asthma exacerbations. Results. Four clusters were identified with varying annualized rates of exacerbations. Cluster 1 (n = 272) was represented by subjects with a mean age of 25 years and 52% females. In contrast, cluster 4, most divergent from cluster 1, was represented by subjects with the highest rate of asthma exacerbations (1.18 events per year), was mostly female (>80%), with a mean body mass index of 34, and was distinguished by the report of stress and emotions as the cause for prior exacerbations. Lower lung function and increased rescue medication use was also reported in cluster 4. Additionally, genetic analysis revealed a significant difference in distribution of genotypes among the four clusters for rs4950928, a single nucleotide polymorphism (SNP) located in the promoter region of the CHI3L1, the chitinase 3-like 1 gene encoding YKL-40. Conclusions. African-Americans who reported stress and emotions as a primary historical cause of exacerbations had the highest annualized rate of exacerbation. Further, a significant correlation with the genotypes in CHI3L1/YKL-40 was observed in the context of stress and asthma severity.

Biologic treatment eligibility for real-world patients with severe asthma: The IDEAL study

ABSTRACT Objectives: Severe asthma comprises several distinct phenotypes. Consequently, patients with severe asthma can be eligible for more than one biologic treatment targeting Th2 inflammation, such as anti-interleukin (IL)-5 and anti-immunoglobulin (Ig) E. The objective of this study was to describe treatment eligibility and overlap in treatment eligibility for mepolizumab (anti-IL-5), omalizumab (anti-IgE) and reslizumab (anti-IL-5) in patients with severe asthma, who were recruited from clinical practice. Methods: This cross-sectional, single-visit, observational study in six countries enrolled patients with severe asthma (defined by American Thoracic Society/European Respiratory Society guidelines). Assessable patients were analysed as a total cohort and a sub-cohort, who were not currently receiving omalizumab. Treatment eligibility was defined according to the local prescribing information or protocol-defined inclusion/exclusion criteria. Patients currently receiving omalizumab were automatically categorised as omalizumab-eligible. Results: The total cohort comprised 670 patients who met the analysis criteria, of whom 20% were eligible for mepolizumab, 31–41% were eligible for omalizumab (depending on eligibility criteria used), and 5% were eligible for reslizumab. In patients not currently receiving omalizumab (n = 502), proportions eligible for each biologic were similar (mepolizumab: 20%, reslizumab 6%) or lower (omalizumab 7–21%) than those for the total cohort. Overlap in treatment eligibility varied; in mepolizumab-eligible patients not currently receiving omalizumab (n = 101), 27–37% were omalizumab-eligible and 18% were reslizumab-eligible. Conclusions: Treatment eligibility for mepolizumab and omalizumab was higher than that for reslizumab. Although there was some overlap in treatment eligibility, the patient groups eligible for treatment with anti-IL-5 or anti-IgE therapies were often distinct, emphasising the different phenotypes and endotypes in severe asthma.

Stability of Blood Eosinophil Count in Patients with COPD in the UK Clinical Practice Research Datalink

ABSTRACT Blood eosinophil counts may be predictive of corticosteroid response in chronic obstructive pulmonary disease (COPD) patients. However, little is known about measurement stability, which is important for understanding the utility of blood eosinophil counts as a potential biomarker. We evaluated the stability of blood eosinophil counts over 1 year in a population-based cohort of patients with COPD in primary care. Patients were aged ≥ 40 years with forced expiratory volume in 1 second/forced vital capacity < 0.7 and ≥ 1 blood eosinophil measurement taken during a period of stable disease within 6 months of a COPD diagnosis code recorded between January 1, 2010 and December 31, 2012. Generalized linear mixed models were fitted to log-transformed data to estimate the between-(s2between) and within-patient (s2within) variance in eosinophil count; an intra-class correlation coefficient Ri was calculated (s2between/[s2between + s2within]). A sensitivity analysis was performed from which patients who were prescribed systemic corticosteroids or antibiotics at any time during follow-up were excluded. All models were adjusted for age, gender, smoking status, and asthma history. Overall, 27,557 patients were included in the full cohort (51.5% male, mean age [standard deviation] 71.1 [10.6] years) and 54% of patients had ≥ 2 eosinophil measurements (median 2 [interquartile range 1]) during follow-up. For the full cohort, Ri = 0.64, and in the sensitivity analysis subgroup, Ri = 0.70, mainly due to a decrease in s2within. For patients with COPD in primary care, eosinophil measurements demonstrated reasonable repeatability over 1 year, which increased after exclusion of patients who were prescribed systemic corticosteroids or antibiotics.

Obstructive airway disease and edentulism in the atherosclerosis risk in communities (ARIC) study

Objectives We examined the potential association between prior chronic obstructive pulmonary disease (COPD) and edentulism, and whether the association varied by COPD severity using data from the Dental Atherosclerosis Risk in Communities Study. Design Cross-sectional. Setting Community dwelling subjects from four US communities. Participants and measurements Cases were identified as edentulous (without teeth) and subjects with one or more natural teeth were identified as dentate. COPD cases were defined by spirometry measurements that showed the ratio of forced expiratory volume (1 s) to vital capacity to be less than 0.7. The severity of COPD cases was also determined using a modified Global Initiative for Chronic Obstructive Lung Disease classification criteria (GOLD stage I–IV). Multiple logistic regression was used to examine the association between COPD and edentulism, while adjusting for age, gender, centre/race, ethnicity, education level, income, diabetes, hypertension, coronary heart disease and congestive heart failure, body mass index, smoking, smokeless tobacco use and alcohol consumption. Results 13 465 participants were included in this analysis (2087 edentulous; 11 378 dentate). Approximately 28.3% of edentulous participants had prior COPD compared with 19.6% among dentate participants (p<0.0001). After adjustment for potential confounders, we observed a 1.3 (1.08 to 1.62) and 2.5 (1.68 to 3.63) fold increased risk of edentulism among GOLD II and GOLD III/IV COPD, respectively, as compared with the non-COPD/dentate referent. Given the short period of time between the measurements of COPD (visit 2) and dentate status (visit 4) relative to the natural history of both diseases, neither temporality nor insight as to the directionality of the association can be ascertained. Conclusions We found a statistically significant association between prior COPD and edentulism, with evidence of a positive incremental effect seen with increasing GOLD classification.

The impact of long-term systemic glucocorticoid use in severe asthma: A UK retrospective cohort analysis

ABSTRACT Objective: Systemic glucocorticoids (SGCs) are a treatment option for severe asthma but are associated with the development of adverse events (AEs). Evidence on the extent of SGC use and the relationship between SGC dose and AE risk in severe asthma is limited. Methods: Patients with severe asthma (Global Initiative for Asthma step 4/5), with no SGC use during the <6–12 months before severe asthma determination (index date) were identified in the UK-based Clinical Practice Research Datalink database (2004–2012). Patients were assessed for SGC exposure and an incident diagnosis of an SGC-related AE (cataracts, diabetes, myocardial infarction [MI], osteoporosis, peptic ulcer or stroke) during the 8-year observation phase. The dose-related risk of an SGC-related AE was determined using AE-specific Cox proportional hazards models. Results: Overall, 75% of 60,418 patients identified with severe asthma received SGC during the 8-year follow-up, with the majority receiving an average of >0–≤2.5 mg/day. The risk of diabetes (hazard ratio [HR]:1.20 [95% confidence interval (CI): 1.11, 1.30]), MI (HR: 1.25 [95% CI: 1.09, 1.43]) and osteoporosis (HR: 1.64 [95% CI: 1.51, 1.78]) was increased at low SGC doses (0–2.5 mg/day), with further risk increases at doses >2.5 mg/day versus no SGC use. Compared with no SGC use, SGC increased the risk of peptic ulcer in a non-dose-dependent manner, but the risk of stroke was unchanged. Conclusions: Most patients with severe asthma are exposed to SGC, which increases SGC-related AE risk. This suggests that SGC exposure should be minimized as recommended by asthma treatment guidelines.

Demographic and Clinical Characteristics of COPD Patients at Different Blood Eosinophil Levels in the UK Clinical Practice Research Datalink

ABSTRACT Blood eosinophil count may be a useful biomarker for predicting response to inhaled corticosteroids and exacerbation risk in chronic obstructive pulmonary disease (COPD) patients. The optimal cut point for categorizing blood eosinophil counts in these contexts remains unclear. We aimed to determine the distribution of blood eosinophil count in COPD patients and matched non-COPD controls, and to describe demographic and clinical characteristics at different cut points. We identified COPD patients within the UK Clinical Practice Research Database aged ≥40 years with a FEV1/FVC <0.7, and ≥1 blood eosinophil count recorded during stable disease between January 1, 2010 and December 31, 2012. COPD patients were matched on age, sex, and smoking status to non-COPD controls. Using all blood eosinophil counts recorded during a 12-month period, COPD patients were categorized as “always above,” “fluctuating above and below,” and “never above” cut points of 100, 150, and 300 cells/μL. The geometric mean blood eosinophil count was statistically significantly higher in COPD patients versus matched controls (196.6 cells/µL vs. 182.1 cells/µL; mean difference 8%, 95% CI: 6.8, 9.2), and in COPD patients with versus without a history of asthma (205.0 cells/µL vs. 192.2 cells/µL; mean difference 6.7%, 95%, CI: 4.9, 8.5). About half of COPD patients had all blood eosinophil counts above 150 cells/μL; this persistent higher eosinophil phenotype was associated with being male, higher body mass index, and history of asthma. In conclusion, COPD patients demonstrated higher blood eosinophil count than non-COPD controls, although there was substantial overlap in the distributions. COPD patients with a history of asthma had significantly higher blood eosinophil count versus those without.