Exacerbations and time spent outdoors in chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease have a progressive reduction in activity, although its time scale and the contribution of exacerbations are unknown. A rolling cohort of 147 patients (101 male; mean age, 88.5 years; and forced expiratory volume in 1 second as percent predicted, 38.4%) were monitored for a median of 1,044 days (interquartile range, 685 to 1,779) over an 8-year period starting in March 1996. Patients recorded any increase in daily respiratory symptoms and time spent outside their home. They completed the St. George's Respiratory Questionnaire yearly. They experienced 1,465 exacerbations and time outdoors decreased by -0.16 hours/day per year (p < 0.001). This decline was faster in frequent exacerbators (p = 0.011). Before exacerbation, the patients stayed indoors all day for 2.1 days/week (on any day 34.1% were at home), but for 5 weeks postexacerbation they spent 2.5 days/week at home (p < 0.001) (44.4% remaining at home at onset; p = 0.021). St. George's total, activity, and impact scores were independently associated with time outdoors (p < 0.005), but not with symptom score. In conclusion, time spent outside the home declines over time and acutely at exacerbation. Patients with frequent exacerbations are more likely to become housebound and need targeting in rehabilitation programs.