Purpose: Recent data show use of health care services by COPD patients is high and repeated admissions for exacerbations are common. Although pulmonary rehabilitation (PR) programs are often thought of as providing rehabilitation only, this study shows that PR programs can detect and address both major and minor health events in COPD patients. Methods: Patient events that prompted physician calls during PR sessions were logged from 1/96 through 3/98. Events were categorized as symptoms change or condition change; responses were categorized as no care alteration, minor care alteration, or major care alteration (hospitalization or ER visit). All COPD patients were risk stratified using the ATS recommended staging system (FEV1 ≤ 50 = Stage 1; FEV1 35-49% = Stage 2; and FEV1 less than 35 = Stage 3). Because FEV1s above 70 are often considered normal, we have added a category which we call Stage 0 for patients whose FEV1 is ≤ 70% and refer to patients with FEV1s of 50-69% as Stage 1. Results: Of the 71 COPD patients enrolled, the FEV1 was unavailable in 5 patients. Among the remaining 66 patients, 12 (18%) were in Stage 0; 8 (12%) in Stage 1; 18 (27%) in Stage 2; and 28 (42%) in Stage 3. Thirty-five events were recorded in 15 patients. Of the 35 events recorded, 31 (89%) were symptoms changes and 4 (11%) were condition changes. Two patients could not be staged due to the missing FEV1 data. Table 1 shows the distribution of events and patients among the four stages. The number of events per patient ranged from one to nine. Four events required major care alterations, 21 required minor care alterations, and 10 required no care alterations. Conclusions: These results indicate that the ATS staging system is a good predictor of events prompting both minor and major care alterations. In addition, they also provide justification for the utilization of Stage 0 in risk stratifying COPD patients. Stage 0 Stage 1 Stage 2 Stage 3 Patients 0 2 3 8 Events 0 5 3 24.