David P. Miller

CREAL Center for Research in Environmental Epidemiology, Barcino, Catalonia, Spain

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Publications (12)11.88 Total impact

  • Hector Ortega, David P Miller, Hao Li
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    ABSTRACT: Patients with a history of asthma exacerbations are at a higher risk for future episodes of severe asthma exacerbations. Characterization of asthma phenotypes could help improve asthma management, including reducing exacerbations. The aim of this study is to identify distinctive patient characteristics associated with a history of asthma exacerbations using cluster analysis. We used data assessing asthma control from two cross-sectional surveys of adult and pediatric patients in the primary care setting. A supervised cluster analysis with recursive partitioning approach was applied to identify characteristics that maximized the differences across subgroups. The sample comprised 2205 adults and 2435 children and adolescents with asthma. Key predictors were identified in seven adult clusters including visiting an asthma specialist, number of hours worked, and excessive use of rescue medication. The rate ratio (RR) for having an exacerbation was significantly higher (2.88; 95% confidence interval (CI), 2.46-3.36) in Cluster 7, with more female patients reporting severe disease, high body mass index, sinus infections, gastroesophageal reflux disease, skin allergies, and lower asthma control score. Features identified in the six pediatric clusters included visiting an asthma specialist, missed school days, race/ethnicity, and age. The RR for having an exacerbation was higher in Cluster 6 (2.36; 95% CI, 2.11-2.64), with patients reporting more severe disease, sinus and skin allergies, and lower asthma control score. Identification of specific risk factors can be enhanced by using supervised cluster analysis. This approach allows grouping of patients with unique characteristics to help identify patients at higher risk of exacerbations.
    Journal of Asthma 03/2012; 49(2):158-69. · 1.83 Impact Factor
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    ABSTRACT: Hospitalisations and their sequelae comprise key morbidities in the natural history of chronic obstructive pulmonary disease (COPD). A study was undertaken to examine the associations between lung function impairment and COPD hospitalisation, and COPD hospitalisation and mortality. The analysis included a population-based sample of 20,571 participants with complete demographic, lung function, smoking, hospitalisation and mortality data, with 10-year median follow-up. Participants were classified by prebronchodilator lung function according to the modified Global Initiative on Obstructive Lung Disease (GOLD) criteria. Hospitalisations were defined by the presence of a COPD discharge diagnosis (ICD-9 codes 490-496). Incidence rate ratios (IRR) of COPD admissions and hazard ratios (HR) of mortality with respective 95% CI were calculated, adjusted for potential confounders. The prevalence of modified GOLD categories was normal (36%), restricted (15%), GOLD stage 0 (22%), GOLD stage 1 (13%), GOLD stage 2 (11%) and GOLD stages 3 or 4 (3%). Adjusted IRRs (and 95% CI) indicated an increased risk of COPD hospitalisation associated with each COPD stage relative to normal lung function: 4.7 (3.7 to 6.1), 2.1 (1.6 to 2.6), 3.2 (2.6 to 4.0), 8.0 (6.4 to 10.0) and 25.5 (19.5 to 33.4) for the restricted, GOLD stage 0, GOLD stage 1, GOLD stage 2 and GOLD stages 3 or 4, respectively. Hospitalisation for COPD increased the risk of subsequent mortality (HR 2.7, 95% CI 2.5 to 3.0), controlling for severity, number of prior hospitalisations and other potential confounders. The increase in mortality associated with admission was very similar across the modified GOLD stages. COPD severity was associated with a higher rate of severe exacerbations requiring hospitalisation, although severe exacerbations at any stage were associated with a higher risk of short-term and long-term all-cause mortality.
    Thorax 07/2011; 66(7):585-90. · 8.56 Impact Factor
  • Kourtney J. Davis, Chao Lu, David P. Miller
    American Thoracic Society 2011 International Conference, May 13-18, 2011 • Denver Colorado; 05/2011
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    ABSTRACT: Some large population-based studies have reported a dose-related increased risk of cataracts and glaucoma associated with use of inhaled corticosteroids (ICS) in patients with asthma or chronic obstructive pulmonary disease (COPD). We evaluated the association between use of ICS-containing products, specifically fluticasone propionate/salmeterol fixed-dose combination (FSC), and incidence of cataracts and glaucoma among patients with COPD in a large electronic medical record database in the United Kingdom. We identified a cohort of patients aged 45 years and over with COPD in the General Practice Research Database (GPRD) between 2003 and 2006. Cases of incident cataracts or glaucoma were defined based on diagnosis and procedure codes and matched to controls from the risk set to estimate odds ratios (OR) and 95% confidence intervals (CI). The association with FSC or ICS exposure was modeled using conditional logistic regression. Medication exposure was assessed with respect to recency, duration, and number of prescriptions prior to the index date. Average daily dose was defined as none, low (1-250 mcg), medium (251-500 mcg), high (501-1000 mcg), or very high (1001+ mcg) using fluticasone propionate (FP) equivalents. We identified 2941 incident cataract cases and 327 incident glaucoma cases in the COPD cohort (n = 53,191). FSC or ICS prescriptions were not associated with risk of incident cataracts or glaucoma for any exposure category, after adjusting for confounders. We observed a lack of a dose response in all analyses, where low dose was the reference group. The odds of cataracts associated with FSC dose were medium OR: 1.1 (95% CI: 0.9-1.4); high OR: 1.2 (95% CI: 0.9-1.5); and very high OR: 1.2 (95% CI: 0.9-1.7). The odds of glaucoma associated with FSC dose: medium OR: 1.0 (95% CI: 0.5-2.1); high OR: 1.0 (95% CI: 0.5-2.0); and very high OR: 1.0 (95% CI: 0.4-2.8). FSC or other ICS exposure was not associated with an increased odds of cataracts or glaucoma, nor was a dose-response relationship observed in this population-based nested case-control study of COPD patients in the United Kingdom.
    International Journal of COPD 01/2011; 6:467-76.
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    ABSTRACT: There has been inconsistent evidence on the association between use of inhaled corticosteroids (ICS) and increased risk of nonvertebral fractures in patients with asthma or chronic obstructive pulmonary disease (COPD). In a large population-based study in the United Kingdom, we estimated the association between fluticasone propionate/salmeterol fixed-dose combination (FSC) and other ICS use and nonvertebral fracture incidence among patients with COPD. We identified a cohort of patients aged ≥ 45 years with COPD in the General Practice Research Database (GPRD) between 2003 and 2006. We used a nested case-control design to estimate the odds of incident nonvertebral fractures associated with prior prescriptions of FSC and other ICS, applying conditional logistic regression and controlling for potential confounders. Exposure to FSC and other ICS was assessed by recency, duration, and number of prescriptions. Average daily dose was defined as low, medium, high, or very high using fluticasone propionate equivalents. We identified 1523 nonvertebral fracture cases among 53 191 patients with COPD at risk in the cohort. Use of FSC in the year prior to the index date was associated with a statistically significant increase in the odds of nonvertebral fractures (odds ratio [OR], 1.25; 95% confidence interval [CI], 1.07-1.47); however, there was no increase in the odds of nonvertebral fractures for other ICS use (OR, 1.12; 95% CI, 0.97-1.30). When examining results by the recent use of prescriptions, an exposure that occurred farther from the index date was associated with a significant increase in nonvertebral fracture (26-52 days prior OR, 1.36; 95% CI, 1.04-1.77; 53-365 days prior OR, 1.39; 95% CI, 1.07-1.78), whereas categories of more recent use (0-12 days prior or 13-25 days prior) were not associated with nonvertebral fractures relative to no FSC use. No pattern of association between increasing levels of FSC or other ICS average daily dose and increased odds of nonvertebral fracture was observed. We did not observe a consistent association between prescriptions of FSC or other ICS in terms of recent use or average daily dose in the prior year and increases in the odds of nonvertebral fractures in patients with COPD, although ever use of FSC was associated with a slight elevation in the odds.
    The Physician and sportsmedicine 12/2010; 38(4):19-27. · 1.49 Impact Factor
  • American Thoracic Society 2010 International Conference, May 14-19, 2010 • New Orleans; 05/2010
  • David P. Miller, David M. Mannino, Bruce Althoff
    American Thoracic Society 2010 International Conference, May 14-19, 2010 • New Orleans; 05/2010
  • David P. Miller, David M. Mannino, Bruce Althoff
    American Thoracic Society 2010 International Conference, May 14-19, 2010 • New Orleans; 05/2010
  • David P. Miller, Sanjay Sharma, Amanda Emmett, Hao Li
    American Thoracic Society 2010 International Conference, May 14-19, 2010 • New Orleans; 05/2010
  • David P. Miller, David M. Mannino, Bruce Althoff
    American Thoracic Society 2010 International Conference, May 14-19, 2010 • New Orleans; 05/2010
  • American Thoracic Society 2010 International Conference, May 14-19, 2010 • New Orleans; 05/2010
  • Sanjay Sharma, David P. Miller, Amanda Emmett, Hao Li
    American Thoracic Society 2010 International Conference, May 14-19, 2010 • New Orleans; 05/2010