Early Diagnosis and Treatment of COPD and Asthma - A Randomized, Controlled Trial.

BACKGROUND: Many persons with chronic obstructive pulmonary disease (COPD) or asthma have not received a diagnosis, so their respiratory symptoms remain largely untreated. METHODS: We used a case-finding method to identify adults in the community with respiratory symptoms without diagnosed lung disease. Participants who were found to have undiagnosed COPD or asthma on spirometry were enrolled in a multicenter, randomized, controlled trial to determine whether early diagnosis and treatment reduces health care utilization for respiratory illness and improves health outcomes. Participants were assigned to receive the intervention (evaluation by a pulmonologist and an asthma-COPD educator who were instructed to initiate guideline-based care) or usual care by their primary care practitioner. The primary outcome was the annualized rate of participant-initiated health care utilization for respiratory illness. Secondary outcomes included changes from baseline to 1 year in disease-specific quality of life, as assessed with the St. George Respiratory Questionnaire (SGRQ; scores range from 0 to 100, with lower scores indicating better health status); symptom burden, as assessed with the COPD Assessment Test (CAT; scores range from 0 to 40, with lower scores indicating better health status); and forced expiratory volume in 1 second (FEV1). RESULTS: Of 38,353 persons interviewed, 595 were found to have undiagnosed COPD or asthma and 508 underwent randomization: 253 were assigned to the intervention group and 255 to the usual-care group. The annualized rate of a primary-outcome event was lower in the intervention group than in the usual-care group (0.53 vs. 1.12 events per person-year; incidence rate ratio, 0.48; 95% confidence interval [CI], 0.36 to 0.63; P<0.001). At 12 months, the SGRQ score was lower than the baseline score by 10.2 points in the intervention group and by 6.8 points in the usual-care group (difference, -3.5 points; 95% CI, -6.0 to -0.9), and the CAT score was lower than the baseline score by 3.8 points and 2.6 points, respectively (difference, -1.3 points; 95% CI, -2.4 to -0.1). The FEV1 increased by 119 ml in the intervention group and by 22 ml in the usual-care group (difference, 94 ml; 95% CI, 50 to 138). The incidence of adverse events was similar in the trial groups. CONCLUSIONS: In this trial in which a strategy was used to identify adults in the community with undiagnosed asthma or COPD, those who received pulmonologist-directed treatment had less subsequent health care utilization for respiratory illness than those who received usual care. (Funded by Canadian Institutes of Health Research; UCAP ClinicalTrials.gov number, NCT03148210.).

Impact of Undiagnosed Chronic Obstructive Pulmonary Disease and Asthma on Symptoms, Quality of Life, Healthcare Use, and Work Productivity.

Rationale: A significant proportion of individuals with chronic obstructive pulmonary disease (COPD) and asthma remain undiagnosed. Objectives: The objective of this study was to evaluate symptoms, quality of life, healthcare use, and work productivity in subjects with undiagnosed COPD or asthma compared with those previously diagnosed, as well as healthy control subjects. Methods: This multicenter population-based case-finding study randomly recruited adults with respiratory symptoms who had no previous history of diagnosed lung disease from 17 Canadian centers using random digit dialing. Participants who exceeded symptom thresholds on the Asthma Screening Questionnaire or the COPD Diagnostic Questionnaire underwent pre- and post-bronchodilator spirometry to determine if they met diagnostic criteria for COPD or asthma. Two control groups, a healthy group without respiratory symptoms and a symptomatic group with previously diagnosed COPD or asthma, were similarly recruited. Measurements and Main Results: A total of 26,905 symptomatic individuals were interviewed, and 4,272 subjects were eligible. Of these, 2,857 completed pre- and post-bronchodilator spirometry, and 595 (21%) met diagnostic criteria for COPD or asthma. Individuals with undiagnosed COPD or asthma reported greater impact of symptoms on health status and daily activities, worse disease-specific and general quality of life, greater healthcare use, and poorer work productivity than healthy control subjects. Individuals with undiagnosed asthma had symptoms, quality of life, and healthcare use burden similar to those of individuals with previously diagnosed asthma, whereas subjects with undiagnosed COPD were less disabled than those with previously diagnosed COPD. Conclusions: Undiagnosed COPD or asthma imposes important, unmeasured burdens on the healthcare system and is associated with poor health status and negative effects on work productivity.

Airway inflammation and hyperresponsiveness in subjects with respiratory symptoms and normal spirometry.

BACKGROUND: Subjects without a previous history of asthma, presenting with unexplained respiratory symptoms and normal spirometry, may exhibit airway hyperresponsiveness (AHR) in association with underlying eosinophilic (type 2 (T2)) inflammation, consistent with undiagnosed asthma. However, the prevalence of undiagnosed asthma in these subjects is unknown. METHODS: In this observational study, inhaled corticosteroid-naïve adults without previously diagnosed lung disease reporting current respiratory symptoms and showing normal pre- and post-bronchodilator spirometry underwent fractional exhaled nitric oxide (F ENO) measurement, methacholine challenge testing and induced sputum analysis. AHR was defined as a provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 s (PC20) <16 mg·mL-1 and T2 inflammation was defined as sputum eosinophils >2% and/or F ENO >25 ppb. RESULTS: Out of 132 subjects (mean±sd age 57.6±14.2 years, 52% female), 47 (36% (95% CI 28-44%)) showed AHR: 20/132 (15% (95% CI 9-21%)) with PC20 <4 mg·mL-1 and 27/132 (21% (95% CI 14-28%)) with PC20 4-15.9 mg·mL-1. Of 130 participants for whom sputum eosinophils, F ENO or both results were obtained, 45 (35% (95% CI 27-43%)) had T2 inflammation. 14 participants (11% (95% CI 6-16%)) had sputum eosinophils >2% and PC20 ≥16 mg·mL-1, suggesting eosinophilic bronchitis. The prevalence of T2 inflammation was significantly higher in subjects with PC20 <4 mg·mL-1 (12/20 (60%)) than in those with PC20 4-15.9 mg·mL-1 (8/27 (30%)) or ≥16 mg·mL-1 (25/85 (29%)) (p=0.01). CONCLUSIONS: Asthma, underlying T2 airway inflammation and eosinophilic bronchitis may remain undiagnosed in a high proportion of symptomatic subjects in the community who have normal pre- and post-bronchodilator spirometry.

Patient and physician factors associated with symptomatic undiagnosed asthma or COPD.

BACKGROUND: It remains unclear why some symptomatic individuals with asthma or COPD remain undiagnosed. Here, we compare patient and physician characteristics between symptomatic individuals with obstructive lung disease (OLD) who are undiagnosed and individuals with physician-diagnosed OLD. METHODS: Using random-digit dialling and population-based case finding, we recruited 451 participants with symptomatic undiagnosed OLD and 205 symptomatic control participants with physician-diagnosed OLD. Data on symptoms, quality of life and healthcare utilisation were analysed. We surveyed family physicians of participants in both groups to elucidate differences in physician practices that could contribute to undiagnosed OLD. RESULTS: Participants with undiagnosed OLD had lower mean pre-bronchodilator forced expiratory volume in 1 s percentage predicted compared with those who were diagnosed (75.2% versus 80.8%; OR 0.975, 95% CI 0.963-0.987). They reported greater psychosocial impacts due to symptoms and worse energy and fatigue than those with diagnosed OLD. Undiagnosed OLD was more common in participants whose family physicians were practising for >15 years and in those whose physicians reported that they were likely to prescribe respiratory medications without doing spirometry. Undiagnosed OLD was more common among participants who had never undergone spirometry (OR 10.83, 95% CI 6.18-18.98) or who were never referred to a specialist (OR 5.92, 95% CI 3.58-9.77). Undiagnosed OLD was less common among participants who had required emergency department care (OR 0.44, 95% CI 0.20-0.97). CONCLUSIONS: Individuals with symptomatic undiagnosed OLD have worse pre-bronchodilator lung function and present with greater psychosocial impacts on quality of life compared with their diagnosed counterparts. They were less likely to have received appropriate investigations and specialist referral for their respiratory symptoms.

Anticipating undiagnosed asthma in symptomatic adults with normal pre- and post-bronchodilator spirometry: a decision tool for bronchial challenge testing.

BACKGROUND: Some patients with asthma demonstrate normal spirometry and remain undiagnosed without further testing. OBJECTIVE: To determine clinical predictors of asthma in symptomatic adults with normal spirometry, and to generate a tool to help clinicians decide who should undergo bronchial challenge testing (BCT). METHODS: Using random-digit dialling and population-based case-finding, we recruited adults from the community with respiratory symptoms and no previous history of diagnosed lung disease. Participants with normal pre- and post-bronchodilator spirometry subsequently underwent BCT. Asthma was diagnosed in those with symptoms and a methacholine provocative concentration (PC20) of < 8 mg/ml. Sputum and blood eosinophils, and exhaled nitric oxide were measured. Univariate analyses identified potentially predictive variables, which were then used to construct a multivariable logistic regression model to predict asthma. Model sensitivity, specificity, and area under the receiver operating curve (AUC) were calculated. RESULTS: Of 132 symptomatic individuals with normal spirometry, 34 (26%) had asthma. Of those ultimately diagnosed with asthma, 33 (97%) answered 'yes' to a question asking whether they experienced cough, chest tightness or wheezing provoked by exercise or cold air. Other univariate predictors of asthma included female sex, pre-bronchodilator FEV1 percentage predicted, and percent positive change in FEV1 post bronchodilator. A multivariable model containing these predictive variables yielded an AUC of 0.82 (95% CI: 0.72-0.91), a sensitivity of 82%, and a specificity of 66%. The model was used to construct a nomogram to advise clinicians which patients should be prioritized for BCT. CONCLUSIONS: Four readily available patient characteristics demonstrated a high sensitivity and AUC for predicting undiagnosed asthma in symptomatic adults with normal pre- and post-bronchodilator spirometry. These characteristics can potentially help clinicians to decide which individuals with normal spirometry should be investigated with bronchial challenge testing. However, further prospective validation of our decision tool is required.

Derivation and validation of the UCAP-Q case-finding questionnaire to detect undiagnosed asthma and COPD.

BACKGROUND: Many people with asthma and COPD remain undiagnosed. We developed and validated a new case-finding questionnaire to identify symptomatic adults with undiagnosed obstructive lung disease. METHODS: Adults in the community with no prior history of physician-diagnosed lung disease who self-reported respiratory symptoms were contacted via random-digit dialling. Pre- and post-bronchodilator spirometry was used to confirm asthma or COPD. Predictive questions were selected using multinomial logistic regression with backward elimination. Questionnaire performance was assessed using sensitivity, predictive values and area under the receiver operating characteristic curve (AUC). The questionnaire was assessed for test-retest reliability, acceptability and readability. External validation was prospectively conducted in an independent sample and predictive performance re-evaluated. RESULTS: A 13-item Undiagnosed COPD and Asthma Population Questionnaire (UCAP-Q) case-finding questionnaire to predict undiagnosed asthma or COPD was developed. The most appropriate risk cut-off was determined to be 6% for either disease. Applied to the derivation sample (n=1615), the questionnaire yielded a sensitivity of 92% for asthma and 97% for COPD; specificity of 17%; and an AUC of 0.69 (95% CI 0.64-0.74) for asthma and 0.82 (95% CI 0.78-0.86) for COPD. Prospective validation using an independent sample (n=471) showed sensitivities of 93% and 92% for asthma and COPD, respectively; specificity of 19%; with AUCs of 0.70 (95% CI 0.62-0.79) for asthma and 0.81 (95% CI 0.74-0.87) for COPD. AUCs for UCAP-Q were higher compared to AUCs for currently recommended case-finding questionnaires for asthma or COPD. CONCLUSIONS: The UCAP-Q demonstrated high sensitivities and AUCs for identifying undiagnosed asthma or COPD. A web-based calculator allows for easy calculation of risk probabilities for each disease.

Population-based case-finding to identify subjects with undiagnosed asthma or COPD.

BACKGROUND: ∼5-10% of adults may have undiagnosed airflow obstruction. The objective of this study was to develop a population-based case-finding strategy to assess the prevalence of undiagnosed airflow obstruction (asthma or COPD) amongst adults with respiratory symptoms in Canada. METHODS: Adults without a previous history of asthma, COPD or lung disease were recruited using random digit-dialling and asked if they had symptoms of dyspnoea, cough, sputum or wheeze within the past 6 months. Those who answered affirmatively completed the Asthma Screening Questionnaire (ASQ), COPD-Diagnostic Questionnaire (COPD-DQ) and COPD Assessment Test (CAT). Those with an ASQ score of ≥6 or a COPD-DQ score of ≥20 underwent pre- and post-bronchodilator spirometry to diagnose asthma or COPD. RESULTS: 12 117 individuals were contacted at home and assessed for study eligibility. Of the 1260 eligible individuals, 910 (72%) enrolled and underwent spirometry. Ultimately, 184 subjects (20% of those enrolled) had obstructive lung disease (73 asthma and 111 COPD). Individuals found to have undiagnosed asthma or COPD had more severe respiratory symptoms and impaired quality of life compared with those without airflow obstruction. The ASQ, COPD-DQ, and CAT had ROC areas for predicting undiagnosed asthma or COPD of 0.49, 0.64 and 0.56, respectively. Four descriptive variables (age, BMI, sex and pack-years smoked) produced better receiver operating characteristic (ROC) values than the questionnaires (ROC area=0.68). CONCLUSION: 20% of randomly selected individuals who report respiratory symptoms in Canada have undiagnosed airflow obstruction due to asthma or COPD. Questionnaires could exclude subjects at low risk but lack the ability to accurately find subjects with undiagnosed disease.

Reevaluation of Diagnosis in Adults With Physician-Diagnosed Asthma.

Importance: Although asthma is a chronic disease, the expected rate of spontaneous remissions of adult asthma and the stability of diagnosis are unknown. Objective: To determine whether a diagnosis of current asthma could be ruled out and asthma medications safely stopped in randomly selected adults with physician-diagnosed asthma. Design, Setting, and Participants: A prospective, multicenter cohort study was conducted in 10 Canadian cities from January 2012 to February 2016. Random digit dialing was used to recruit adult participants who reported a history of physician-diagnosed asthma established within the past 5 years. Participants using long-term oral steroids and participants unable to be tested using spirometry were excluded. Information from the diagnosing physician was obtained to determine how the diagnosis of asthma was originally made in the community. Of 1026 potential participants who fulfilled eligibility criteria during telephone screening, 701 (68.3%) agreed to enter into the study. All participants were assessed with home peak flow and symptom monitoring, spirometry, and serial bronchial challenge tests, and those participants using daily asthma medications had their medications gradually tapered off over 4 study visits. Participants in whom a diagnosis of current asthma was ultimately ruled out were followed up clinically with repeated bronchial challenge tests over 1 year. Exposure: Physician-diagnosed asthma established within the past 5 years. Main Outcomes and Measures: The primary outcome was the proportion of participants in whom a diagnosis of current asthma was ruled out, defined as participants who exhibited no evidence of acute worsening of asthma symptoms, reversible airflow obstruction, or bronchial hyperresponsiveness after having all asthma medications tapered off and after a study pulmonologist established an alternative diagnosis. Secondary outcomes included the proportion with asthma ruled out after 12 months and the proportion who underwent an appropriate initial diagnostic workup for asthma in the community. Results: Of 701 participants (mean [SD] age, 51 [16] years; 467 women [67%]), 613 completed the study and could be conclusively evaluated for a diagnosis of current asthma. Current asthma was ruled out in 203 of 613 study participants (33.1%; 95% CI, 29.4%-36.8%). Twelve participants (2.0%) were found to have serious cardiorespiratory conditions that had been previously misdiagnosed as asthma in the community. After an additional 12 months of follow-up, 181 participants (29.5%; 95% CI, 25.9%-33.1%) continued to exhibit no clinical or laboratory evidence of asthma. Participants in whom current asthma was ruled out, compared with those in whom it was confirmed, were less likely to have undergone testing for airflow limitation in the community at the time of initial diagnosis (43.8% vs 55.6%, respectively; absolute difference, 11.8%; 95% CI, 2.1%-21.5%). Conclusions and Relevance: Among adults with physician-diagnosed asthma, a current diagnosis of asthma could not be established in 33.1% who were not using daily asthma medications or had medications weaned. In patients such as these, reassessing the asthma diagnosis may be warranted.

TNFα antagonists for acute exacerbations of COPD: a randomised double-blind controlled trial.

BACKGROUND: The purpose of this randomised double-blind double-dummy placebo-controlled trial was to investigate whether etanercept, a tumour necrosis factor α (TNFα) antagonist, would provide more effective anti-inflammatory treatment for acute exacerbations of chronic obstructive pulmonary disease (COPD) than prednisone. METHODS: We enrolled 81 patients with acute exacerbations of COPD and randomly assigned them to treatment with either 40 mg oral prednisone given daily for 10 days or to 50 mg etanercept given subcutaneously at randomisation and 1 week later. Both groups received levofloxacin for 10 days plus inhaled bronchodilators. The primary endpoint was the change in the patient's forced expiratory volume in 1 s (FEV(1)) 14 days after randomisation. Secondary endpoints included 90-day treatment failure rates and dyspnoea and quality of life. RESULTS: At 14 days the mean±SE change in FEV(1) from baseline was 20.1±5.0% and 15.2±5.7% for the prednisone and etanercept groups, respectively. The mean between-treatment difference was 4.9% (95% CI -10.3% to 20.2%), p=0.52. Rates of treatment failure at 90 days were similar in the prednisone and etanercept groups (32% vs 40%, p=0.44), as were measures of dyspnoea and quality of life. Subgroup analysis revealed that patients with serum eosinophils >2% at exacerbation tended to experience fewer treatment failures if treated with prednisone compared with etanercept (22% vs 50%, p=0.08). CONCLUSIONS: Etanercept was not more effective than prednisone for treatment of acute exacerbations of COPD. Efficacy of prednisone was most apparent in patients who presented with serum eosinophils >2%. CLINICAL TRIALS: gov number NCT 00789997.

Disease burden in individuals with symptomatic undiagnosed asthma or COPD.

BACKGROUND: The actual burden of COPD and asthma may be much higher than appreciated, since a large proportion of individuals are not diagnosed. Our study objective was to compare health care utilization, burden of symptoms and quality of life in subjects with self-reported respiratory symptoms who were subsequently found to have undiagnosed airflow obstruction compared to those having no airflow obstruction. METHODS: This cross-sectional case-finding study used data from the Undiagnosed COPD and Asthma Population (UCAP) study. Adult subjects with respiratory symptoms who had no history of diagnosed lung disease were recruited in a two-step case-finding process using random digit-dialling of land lines and cell phones located within a 90-min radius of 16 Canadian study sites. Participants were assessed for COPD, asthma or no airflow obstruction using pre- and post-bronchodilator spirometry based on American Thoracic Society diagnostic criteria. RESULTS: 1660 participants were recruited, of these 1615 had adequate spirometry and 331 (20.5%) subjects met spirometry criteria for undiagnosed asthma or COPD. Subjects with undiagnosed asthma or COPD had increased respiratory symptoms as assessed by the COPD Assessment Test (CAT), and higher St. George's Respiratory Questionnaire (SGRQ) scores indicating worse health-related quality of life, compared to subjects with no airflow obstruction. No between-group differences were found in health care utilization or work or school absenteeism. CONCLUSION: Undiagnosed asthma and COPD are common in Canadian adults experiencing breathing problems and are associated with a greater burden of symptoms and poorer health-related quality of life. These results suggest that patients may benefit from early identification and treatment of undiagnosed asthma and COPD.

Exacerbation frequency and clinical outcomes in adult patients with cystic fibrosis.

BACKGROUND: Despite advances in treatment of cystic fibrosis (CF), pulmonary exacerbations remain common. The aim of this study was to determine if frequent pulmonary exacerbations are associated with greater declines in lung function, or an accelerated time to death or lung transplantation in adults with CF. METHODS: A 3-year prospective cohort study was conducted on 446 adult patients with CF from Ontario, Canada who could spontaneously produce sputum. Patients enrolled from 2005 to 2008 and were stratified into groups based upon their exacerbation rates over the 3 year study: <1 exacerbation/year (n=140), 1-2 exacerbations/year (n=160) and >2 exacerbations/year (n=146). Exacerbations were defined as acute/subacute worsening of respiratory symptoms severe enough to warrant oral or intravenous antibiotics. Patient-related factors associated with frequent exacerbations were determined, and clinical outcomes were compared among the three exacerbation groups. RESULTS: Patients with frequent exacerbations were more likely to be female, diabetic and have poorer baseline lung function. Patients with >2 exacerbations/year had an increased risk of experiencing a 5% decline from baseline forced expiratory volume in 1 s (FEV(1)); unadjusted HR 1.47 (95% CI 1.07 to 2.01, p=0.02), adjusted HR 1.55 (95% CI 1.10 to 2.18, p=0.01) compared with patients with <1 exacerbation/year. Patients with >2 exacerbations/year also had an increased risk of lung transplant or death over the 3 year study; unadjusted HR 12.74 (95% CI 3.92 to 41.36, p<0.0001), adjusted HR 4.05 (95% CI 1.15 to 14.28, p=0.03). CONCLUSIONS: Patients with CF with frequent exacerbations appear to experience an accelerated decline in lung function, and they have an increased 3 year risk of death or lung transplant.

Multi analyte profiling and variability of inflammatory markers in blood and induced sputum in patients with stable COPD.

BACKGROUND: We analyzed serial concentrations of multiple inflammatory mediators from serum and induced sputum obtained from patients with stable COPD and controls. The objective was to determine which proteins could be used as reliable biomarkers to assess COPD disease state and severity. METHODS: Forty-two subjects; 21 with stable COPD and 21 controls, were studied every 2 weeks over a 6-week period. Serum and induced sputum were obtained at each of 3 visits and concentrations of 19 serum and 22 sputum proteins were serially assessed using multiplex immunoassays. We used linear mixed effects models to test the distribution of proteins for an association with COPD and disease severity. Measures of within- and between-subject coefficients of variation were calculated for each of the proteins to assess reliability of measurement. RESULTS: There was significant variability in concentrations of all inflammatory proteins over time, and variability was greater for sputum proteins (median intra-subject coefficient of variation 0.58) compared to proteins measured in serum (median intra-subject coefficient of variation 0.32, P = 0.03). Of 19 serum proteins and 22 sputum proteins tested, only serum CRP, myeloperoxidase and VEGF and sputum IL-6, IL-8, TIMP-1, and VEGF showed acceptable intra and inter-patient reliability and were significantly associated with COPD, the severity of lung function impairment, and dyspnea. CONCLUSIONS: Levels of many serum and sputum biomarkers cannot be reliably ascertained based on single measurements. Multiple measurements over time can give a more reliable and precise estimate of the inflammatory burden in clinically stable COPD patients.

Randomized trial of a decision aid for patients with cystic fibrosis considering lung transplantation.

RATIONALE: We developed an evidence-based decision aid for patients with advanced cystic fibrosis considering referral for lung transplantation. OBJECTIVES: To prospectively evaluate whether use of the decision aid increased knowledge about the options, improved realistic expectations, and decreased decisional conflict in adult patients. METHODS: We performed a single-blind randomized controlled trial involving 149 adult patients with cystic fibrosis with an FEV(1)

Development of a decision aid for adult cystic fibrosis patients considering referral for lung transplantation.

CONTEXT: Most adults with cystic fibrosis are eventually required to make a decision about referral for lung transplantation. OBJECTIVE: To identify the decisional needs of these patients and to develop a decision aid to address these needs. METHODS: A comprehensive review of the literature, a review of Canadian transplant statistics from 2002 to 2006, and a self-assessment survey of patients who had already made a decision about referral were performed to identify the decisional needs of patients. A decision aid was then developed and evaluated by an expert panel of health care professionals and patients. RESULTS: Transplant referral patterns vary widely among Canadian cystic fibrosis clinics. Canadian patients with cystic fibrosis who were not residing in transplant centers between 2002 and 2006 were significantly less likely to undergo lung transplants (P < .001). Decisional needs identified by patients included wanting more information on (1) relocation to the transplant center, (2) the benefits and risks of surgery, and (3) how to cope with anxiety and depression when making the decision. In response to these identified needs, a decision aid for lung transplantation was developed. A panel of health care professionals and patients reviewed the decision aid and agreed that the content was appropriate, easy to understand, and unbiased. CONCLUSION: The decisional needs of patients with cystic fibrosis who are considering lung transplantation are not being addressed in Canadian cystic fibrosis clinics, especially in clinics outside of transplant centers. An evidence-based decision aid could serve as a useful tool to help address these needs.

Infection with transmissible strains of Pseudomonas aeruginosa and clinical outcomes in adults with cystic fibrosis.

CONTEXT: Studies from Australia and the United Kingdom have shown that some patients with cystic fibrosis are infected with common transmissible strains of Pseudomonas aeruginosa. OBJECTIVES: To determine the prevalence and incidence of infection with transmissible strains of P. aeruginosa and whether presence of the organism was associated with adverse clinical outcomes in Canada. DESIGN, SETTING, AND PARTICIPANTS: Prospective observational cohort study of adult patients cared for at cystic fibrosis clinics in Ontario, Canada, with enrollment from September 2005 to September 2008. Sputum was collected at baseline, 3 months, and yearly thereafter for 3 years; and retrieved P. aeruginosa isolates were genotyped. Vital status (death or lung transplant) was assessed for all enrolled patients until December 31, 2009. MAIN OUTCOME MEASURES: Incidence and prevalence of P. aeruginosa isolation, rates of decline in lung function, and time to death or lung transplantation. RESULTS: Of the 446 patients with cystic fibrosis studied, 102 were discovered to be infected with 1 of 2 common transmissible strains of P. aeruginosa at study entry. Sixty-seven patients were infected with strain A (15%), 32 were infected with strain B (7%), and 3 were simultaneously infected with both strains (0.6%). Strain A was found to be genetically identical to the Liverpool epidemic strain but strain B has not been previously described as an epidemic strain. The incidence rate of new infections with these 2 transmissible strains was relatively low (7.0 per 1000 person-years; 95% confidence interval [CI], 1.8-12.2 per 1000 person-years). Compared with patients infected with unique strains of P. aeruginosa, patients infected with the Liverpool epidemic strain (strain A) and strain B had similar declines in lung function (difference in decline in percent predicted forced expiratory volume in the first second of expiration of 0.64% per year [95% CI, -1.52% to 2.80% per year] and 1.66% per year [95% CI, -1.00% to 4.30%], respectively). However, the 3-year rate of death or lung transplantation was greater in those infected with the Liverpool epidemic strain (18.6%) compared with those infected with unique strains (8.7%) (adjusted hazard ratio, 3.26 [95% CI, 1.41 to 7.54]; P = .01). CONCLUSIONS: A common strain of P. aeruginosa (Liverpool epidemic strain/strain A) infects patients with cystic fibrosis in Canada and the United Kingdom. Infection with this strain in adult Canadian patients with cystic fibrosis was associated with a greater risk of death or lung transplantation.

Performance Characteristics of Spirometry With Negative Bronchodilator Response and Methacholine Challenge Testing and Implications for Asthma Diagnosis.

BACKGROUND: In patients with a history suggestive of asthma, diagnosis is usually confirmed by spirometry with bronchodilator response (BDR) or confirmatory methacholine challenge testing (MCT). RESEARCH QUESTION: We examined the proportion of participants with negative BDR testing who had a positive MCT (and its predictors) result and characteristics of MCT, including effects of controller medication tapering and temporal variability (and predictors of MCT result change), and concordance between MCT and pulmonologist asthma diagnosis. STUDY DESIGN AND METHODS: Adults with self-reported physician-diagnosed asthma were recruited by random-digit dialing across Canada. Subjects performed spirometry with BDR testing and returned for MCT if testing was nondiagnostic for asthma. Subjects on controllers underwent medication tapering with serial MCTs over 3 to 6 weeks. Subjects with a negative MCT (the provocative concentration of methacholine that results in a 20% drop in FEV1 [PC20] > 8 mg/mL) off medications were examined by a pulmonologist and had serial MCTs after 6 and 12 months. RESULTS: Of 500 subjects (50.5 ± 16.6 years old, 68.0% female) with a negative BDR test for asthma, 215 (43.0%) had a positive MCT. Subjects with prebronchodilator airflow limitation were more likely to have a positive MCT (OR, 1.90; 95% CI, 1.17-3.04). MCT converted from negative to positive, with medication tapering in 18 of 94 (19.1%) participants, and spontaneously over time in 25 of 165 (15.2%) participants. Of 231 subjects with negative MCT, 28 (12.1%) subsequently received an asthma diagnosis from a pulmonologist. INTERPRETATION: In subjects with a self-reported physician diagnosis of asthma, absence of bronchodilator reversibility had a negative predictive value of only 57% to exclude asthma. A finding of spirometric airflow limitation significantly increased chances of asthma. MCT results varied with medication taper and over time, and pulmonologists were sometimes prepared to give a clinical diagnosis of asthma despite negative MCT. Correspondingly, in patients for whom a high clinical suspicion of asthma exists, repeat testing appears to be warranted.

Epidemiological investigation and glycotyping of clinical Pseudomonas aeruginosa isolates from patients with cystic fibrosis by mass spectrometry: association with multiple drug resistance.

The aim of the present investigation was to develop a novel approach for rapid identification and differentiation of Pseudomonas aeruginosa clones from Canadian cystic fibrosis patients by capillary electrophoresis-mass spectrometry. We screened P. aeruginosa isolates for lipopolysaccharide structure and presence/absence of alginate and correlated these findings with antibiotic resistance patterns.

Placebo Effects in Clinical Trials Evaluating Patients with Uncontrolled Persistent Asthma.

Rationale: Patients with uncontrolled, persistent asthma can show substantial health improvements when administered placebo.Objectives: We analyzed five randomized, placebo-controlled clinical trials that assessed subjects with uncontrolled, persistent asthma to determine the magnitudes of placebo effects across different clinical outcomes.Methods: Placebo effects for objective asthma-related outcomes, healthcare utilization outcomes, and patient-reported outcomes were estimated, with adjustments for regression to the mean.Results: Statistically significant improvements in all clinical outcomes were seen in patients randomized to placebo across all trials. Placebo effects were largest for healthcare utilization outcomes, including exacerbations (median reduction, 0.44 events/yr; 31% risk reduction; range, 19-56%), emergency department visits (median reduction, 0.19 events/yr; 50% risk reduction; range, 36-82%), and hospitalizations for asthma (median reduction, 0.26 events/yr; 66% risk reduction; range, 61-74%). Patient-reported outcomes exhibited intermediate placebo effects. Median improvements in the Asthma Control Questionnaire and St. George's Respiratory Questionnaire scores in placebo-treated patients were 0.53 units (25% improvement; range, 18-30%) and 8.3 units (19.5% improvement; range 19-20%), respectively. Forced expiratory volume in 1 second exhibited the smallest relative placebo effects (median increase, 77 ml; 4.2% improvement; range, 3.4-4.9%). Subgroup analyses did not reveal patient subgroups that were more susceptible to placebo effects. Pre- and postrandomization counts for asthma exacerbations showed patterns consistent with the expected negative binomial distribution except for significant departures in prerandomization exacerbations for two trials.Conclusions: Patients with uncontrolled asthma derived consistent benefit from randomization to placebo. Observed placebo effects may represent beneficial effects of both sham therapy and a structured asthma regimen dictated by the study protocol. In the case of healthcare utilization outcomes, recall errors in self-reported healthcare events may have introduced biases that inflated placebo effect estimates.

Overdiagnosis of asthma in obese and nonobese adults.

BACKGROUND: It is unclear whether asthma is overdiagnosed in developed countries, particularly among obese individuals, who may be more likely than nonobese people to experience dyspnea. METHODS: We conducted a longitudinal study involving nonobese (body mass index 20-25) and obese (body mass index >/= 30) individuals with asthma that had been diagnosed by a physician. Participants were recruited from 8 Canadian cities by means of random-digit dialing. A diagnosis of current asthma was excluded in those who did not have evidence of acute worsening of asthma symptoms, reversible airflow obstruction or bronchial hyperresponsiveness, despite being weaned off asthma medications. We stopped asthma medications in those in whom a diagnosis of asthma was excluded and assessed their clinical outcomes over 6 months. RESULTS: Of 540 individuals with physician-diagnosed asthma who participated in the study, 496 (242 obese and 254 nonobese) could be conclusively assessed for a diagnosis of asthma. Asthma was ultimately excluded in 31.8% (95% confidence interval [CI] 26.3%-37.9%) in the obese group and in 28.7% (95% CI 23.5%-34.6%) in the nonobese group. Overdiagnosis of asthma was no more likely to occur among obese individuals than among nonobese individuals (p = 0.46). Of those in whom asthma was excluded, 65.5% did not need to take asthma medication or seek health care services because of asthma symptoms during a 6-month follow-up period. INTERPRETATION: About one-third of obese and nonobese individuals with physician-diagnosed asthma did not have asthma when objectively assessed. This finding suggests that, in developed countries such as Canada, asthma is overdiagnosed.