Assessment of patients with chronic obstructive pulmonary disease

Abstract

Assessment of patients with chronic obstructive pulmonary disease (COPD) is important to establish an accurate diagnosis, assist in making therapeutic decisions, measuring outcomes for clinical and research purposes, and determining prognosis. Chest computed tomography (CT) scans are useful in patients who present with airflow limitation and clinical features suggestive of COPD but in whom other diagnoses are being considered. In such cases, a chest CT may indicate another diagnosis. The amount and distribution of emphysema can identify outcomes from lung volume reduction surgery, and chest CT scans are mandatory in assessment of patients for this surgery. Quantitative parameters from chest CT scans have been used to define longitudinal progression of disease. Assessment of patients with COPD for both clinical and research purposes should incorporate a variety of different outcomes. There are outcome measures that have been successfully incorporated in large clinical trials, and the design and outcomes of these trials can be used to plan future clinical investigations in COPD.

Figure 1.

National Emphysema Treatment Trial (NETT) subgroup treatment effects. Effect of lung volume reduction surgery (LVRS) versus medical treatment on mortality, maximal workload achieved on cardiopulmonary exercise testing (improvement of more than 10 watts versus not improved), and disease-specific quality of life as measured by the St. George's Respiratory Questionnaire (SGRQ; improvement of more than 8 units in total score versus not improved). OR = odds ratio; RR = relative risk; *Patients not considered candidates for LVRS by the NETT or approved for LVRS by the Centers for Medicare and Medicaid Services or the Joint Commission on Accreditation of Healthcare Organizations. Reprinted by permission from Reference .

Figure 2.

Probability of death in the National Emphysema Treatment Trial. Kaplan-Meier estimates of the cumulative probability of death as a function of years after randomization to lung volume reduction surgery (LVRS) (gray line) or medical treatment (black line) for (A) all patients and (B) upper lobe–predominant and low baseline exercise capacity subgroup. The P value is from the Fisher's exact test for difference in the proportions of patients who died during the 4.3 years (median) of follow-up. Shown below each graph are the numbers of patients at risk, the Kaplan-Meier probabilities, the ratio of the probabilities (LVRS:medical), and P value for the difference in these probabilities. Reprinted by permission from Reference .

Figure 3.

Exercise capacity results from the National Emphysema Treatment Trial. Improvement in exercise capacity (defined as an increase in maximum work of 10 watts above the patient's post–rehabilitation baseline) at 1, 2, and 3 years after randomization to lung volume reduction surgery (LVRS) (open bars) or medical treatment (shaded bars). Intention to treat analysis of (A) all patients (n = 1,218) and (B) upper lobe–predominant and low baseline exercise capacity (n = 290). Shown below each graph are the numbers of patients evaluated, the odds ratio for improvement (LVRS:medical), and the Fisher's exact P value for difference in proportion improved. Patients who died or who did not complete the assessment were considered not improved (3).