Integrated disease management interventions for patients with chronic obstructive pulmonary disease

Although we know that exacerbations are key events in chronic obstructive pulmonary disease (COPD), our understanding of their frequency, determinants, and effects is incomplete. In a large observational cohort, we tested the hypothesis that there is a frequent-exacerbation phenotype of COPD that is independent of disease severity. We analyzed the frequency and associations of exacerbation in 2138 patients enrolled in the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study. Exacerbations were defined as events that led a care provider to prescribe antibiotics or corticosteroids (or both) or that led to hospitalization (severe exacerbations). Exacerbation frequency was observed over a period of 3 years. Exacerbations became more frequent (and more severe) as the severity of COPD increased; exacerbation rates in the first year of follow-up were 0.85 per person for patients with stage 2 COPD (with stage defined in accordance with Global Initiative for Chronic Obstructive Lung Disease [GOLD] stages), 1.34 for patients with stage 3, and 2.00 for patients with stage 4. Overall, 22% of patients with stage 2 disease, 33% with stage 3, and 47% with stage 4 had frequent exacerbations (two or more in the first year of follow-up). The single best predictor of exacerbations, across all GOLD stages, was a history of exacerbations. The frequent-exacerbation phenotype appeared to be relatively stable over a period of 3 years and could be predicted on the basis of the patient's recall of previous treated events. In addition to its association with more severe disease and prior exacerbations, the phenotype was independently associated with a history of gastroesophageal reflux or heartburn, poorer quality of life, and elevated white-cell count. Although exacerbations become more frequent and more severe as COPD progresses, the rate at which they occur appears to reflect an independent susceptibility phenotype. This has implications for the targeting of exacerbation-prevention strategies across the spectrum of disease severity. (Funded by GlaxoSmithKline; ClinicalTrials.gov number, NCT00292552.)

There is a need for a brief, validated patient self-report instrument to assess the extent to which patients with chronic illness receive care that aligns with the Chronic Care Model-measuring care that is patient-centered, proactive, planned and includes collaborative goal setting; problem-solving and follow-up support. A total of 283 adults reporting one or more chronic illness from a large integrated health care delivery system were studied. Participants completed the 20-item Patient Assessment of Chronic Illness Care (PACIC) as well as measures of demographic factors, a patient activation scale, and subscales from a primary care assessment instrument so that we could evaluate measurement performance, construct, and concurrent validity of the PACIC. The PACIC consists of 5 scales and an overall summary score, each having good internal consistency for brief scales. As predicted, the PACIC was only slightly correlated with age and gender, and unrelated to education. Contrary to prediction, it was only slightly correlated (r = 0.13) with number of chronic conditions. The PACIC demonstrated moderate test-retest reliability (r = 0.58 during the course of 3 months) and was correlated moderately, as predicted (r = 0.32-0.60, median = 0.50, P < 0.001) to measures of primary care and patient activation. The PACIC appears to be a practical instrument that is reliable and has face, construct, and concurrent validity. The resulting questionnaire is in the public domain, and recommendations for its use in research and quality improvement are outlined.

Functional status measurements are often difficult to interpret because small differences may be statistically significant but not clinically significant. How much does the Six Minute Walk test (6MW) need to differ to signify a noticeable difference in walking ability for patients with chronic obstructive pulmonary disease (COPD)? We studied individuals with stable COPD (n = 112, mean age = 67 yr, mean FEV1 = 975 ml) and estimated the smallest difference in 6MW distances that was associated with a noticeable difference in patients' subjective comparison ratings of their walking ability. We found that the 6MW was significantly correlated with patients' ratings of their walking ability relative to other patients (r = 0.59, 95% confidence interval [CI]: 0.54 to 0.63). Distances needed to differ by 54 m for the average patient to stop rating themselves as "about the same" and start rating themselves as either "a little bit better" or "a little bit worse" (95% CI: 37 to 71 m). We suggest that differences in functional status can be statistically significant but below the threshold at which patients notice a difference in themselves relative to others; an awareness of the smallest difference in walking distance that is noticeable to patients may help clinicians interpret the effectiveness of symptomatic treatments for COPD.