Clinical predictors of frequent exacerbations in subjects with severe chronic obstructive pulmonary disease (COPD).

BACKGROUND: Acute exacerbations are a significant source of morbidity and mortality associated with chronic obstructive pulmonary disease. Among individuals with COPD, some patients suffer an inordinate number of exacerbations while others remain relatively protected. We undertook a study to determine the clinical factors associated with "frequent exacerbator" status within a population of subjects with severe COPD. METHODS: Case-control cohort recruited from two Boston-area practices. All subjects had GOLD stage 3 or 4 (FEV(1) ≤ 50% predicted) COPD. "Frequent exacerbators" (n = 192) had an average of ≥2 moderate-to-severe exacerbations per year while "non-exacerbators" (n = 153) had no exacerbations in the preceding 12 months. Multivariate logistic regression was performed to determine the significant clinical predictors of "frequent exacerbator" status. RESULTS: Physician-diagnosed asthma was a significant predictor of frequent exacerbations. Within a subset of our cohort, the modified Medical Research Council dyspnea score and FEF (25-75%) predicted were also significant clinical predictors of frequent exacerbator status (p < 0.05). Differences in exacerbation frequency were not found to be due to increased current tobacco use or decreased rates of maintenance medication use. CONCLUSIONS: Within our severe COPD cohort, a history of physician-diagnosed asthma was found to be a significant clinical predictor of frequent exacerbations. Although traditional risk factors such as decreased FEV(1)% predicted were not significantly associated with frequent exacerbator status, lower mid-expiratory flow rates, as assessed by FEF (25-75%) predicted, were significantly associated with frequent exacerbations in a subset of our cohort.

Adherence to inhaled corticosteroid use and local adverse events in persistent asthma.

OBJECTIVES: To measure adherence to inhaled corticosteroid (ICS) therapy using prescription claims and a patient survey, to identify local adverse events (LAEs) from the patient perspective and from medical records, and to evaluate the association between LAEs and adherence to ICS therapy. STUDY DESIGN: Survey administration and claims-based and medical record-abstracted data. METHODS: Patients aged 6 to 64 years with persistent asthma (defined using an established algorithm) and at least 2 ICS prescriptions were selected from a claims database (1999-2006) of a central Massachusetts medical group practice. Prescription claims were used to calculate the ICS medication possession ratio (MPR). A survey obtained information about patient-reported adherence to ICSs using the Morisky scale and a visual analog scale (VAS) and about LAEs using the validated Inhaled Corticosteroid Questionnaire. Medical records of survey respondents were abstracted for LAEs. RESULTS: Among 372 survey respondents, 2.7% met the claims-based measure of good adherence (MPR, > or =80%). Patient-reported adherence was much higher; 20.7% of patients were highly adherent based on the Morisky scale (score, 0) and 55.4% based on the VAS (score, > or =80%). Medical record review identified 27.2% of patients having at least 1 LAE within 1 year after the ICS index date, but 47.3% of patients reported being bothered at least "quite a lot" by LAEs. Multivariate analysis indicated that unpleasant taste was significantly related to lower adherence based on the Morisky scale (P = .02). CONCLUSIONS: Patient-reported adherence and LAEs were higher than those measured from claims or medical records. Unpleasant taste seems to be associated with lower adherence based on the Morisky scale.

The validation of work-related self-reported asthma exacerbation.

OBJECTIVE: To determine the validity of work-related self-reported exacerbation of asthma using the findings from serial peak expiratory flow (PEF) measurements as the standard. METHODS: Adults with asthma treated in a health maintenance organisation were asked to conduct serial spirometry testing at home and at work for 3 weeks. Self-reported respiratory symptoms and medication use were recorded in two ways: a daily log completed concurrently with the serial PEF testing and a telephone questionnaire administered after the PEF testing. Three researchers evaluated the serial PEF records and judged whether a work relationship was evident. RESULTS: 95 of 382 (25%) working adults with asthma provided adequate serial PEF data, and 13 of 95 (14%) were judged to have workplace exacerbation of asthma (WEA) based on these data. Self-reported concurrent medication use was the most valid single operational definition, with a sensitivity of 62% and a specificity of 65%. CONCLUSIONS: A work-related pattern of self-reported asthma symptoms or medication use was usually not corroborated by serial PEF testing and failed to identify many people who had evidence of WEA based on the serial PEF measurements.

Case-by-case assessment of adult-onset asthma attributable to occupational exposures among members of a health maintenance organization.

OBJECTIVE: In a general population of employed persons with health insurance, what proportion of adult-onset asthma is caused by occupational exposures? METHOD: We conducted a 2-year prospective study to identify adult-onset asthma among health maintenance organization (HMO) members. Telephone interviews regarding occupational exposures, symptoms, medication use, and triggers were used to assess likelihood of work-related asthma for each case. Weighted estimating equations were used to adjust the proportion of asthma attributable to workplace exposures for factors associated with interview participation. RESULTS: Overall, 29% (95% confidence interval, 25-34%) of adult-onset asthma was attributable to workplace exposures; 26% (21-30%) and 22% (18-27%) of cases had asthma attributable to occupational irritant and sensitizer exposures, respectively. CONCLUSIONS: Occupational exposures, including irritants, are important causes of adult-onset asthma.

A longitudinal study of adult-onset asthma incidence among HMO members.

BACKGROUND: HMO databases offer an opportunity for community based epidemiologic studies of asthma incidence, etiology and treatment. The incidence of asthma in HMO populations and the utility of HMO data, including use of computerized algorithms and manual review of medical charts for determining etiologic factors has not been fully explored. METHODS: We identified adult-onset asthma, using computerized record searches in a New England HMO. Monthly, our software applied exclusion and inclusion criteria to identify an "at-risk" population and "potential cases". Electronic and paper medical records from the past year were then reviewed for each potential case. Persons with other respiratory diseases or insignificant treatment for asthma were excluded. Confirmed adult-onset asthma (AOA) cases were defined as those potential cases with either new-onset asthma or reactivated mild intermittent asthma that had been quiescent for at least one year. We validated the methods by reviewing charts of selected subjects rejected by the algorithm. RESULTS: The algorithm was 93 to 99.3% sensitive and 99.6% specific. Sixty-three percent (n = 469) of potential cases were confirmed as AOA. Two thirds of confirmed cases were women with an average age of 34.8 (SD 11.8), and 45% had no evidence of previous asthma diagnosis. The annualized monthly rate of AOA ranged from 4.1 to 11.4 per 1000 at-risk members. Physicians most commonly attribute asthma to infection (59%) and allergy (14%). New-onset cases were more likely attributed to infection, while reactivated cases were more associated with allergies. Medical charts included a discussion of work exposures in relation to asthma in only 32 (7%) cases. Twenty-three of these (72%) indicated there was an association between asthma and workplace exposures for an overall rate of work-related asthma of 4.9%. CONCLUSION: Computerized HMO records can be successfully used to identify AOA. Manual review of these records is important to confirm case status and is useful in evaluation of provider consideration of etiologies. We demonstrated that clinicians attribute most AOA to infection and tend to ignore the contribution of environmental and occupational exposures.