During 1979 to 2001, there were an estimated total of 47,404,700 hospital discharges with a diagnosis of COPD as either the primary or secondary discharge diagnosis (8.5% of all hospitalizations in adults > 25 years old), of which 37,540,374 discharges (79.2%) were listed with COPD as a secondary diagnosis and 9,864,278 discharges (20.8%) were listed with COPD as the primary discharge diagnosis. From 1979 to 2001, the yearly prevalence of hospital discharges with a diagnosis of COPD increased significantly (p for trend < 0.01), mainly due to the proportion of hospital discharges with COPD listed as a secondary diagnosis (mean increase per year, 0.3%; 95% confidence interval, 0.30 to 0.34), in comparison to discharges where COPD was listed as primary diagnosis (mean increase per year, 0.05%; 95% confidence interval, 0.02 to 0.07) [Fig 1]
. The proportion of in-hospital mortality among discharges with and without COPD increased significantly with age (Table 1
). The age-adjusted hospital prevalence of pneumonia, hypertension, heart failure, ischemic heart disease, pulmonary vascular disease, thoracic malignancies, and ventilatory failure were higher among hospital discharges with a diagnosis of COPD when compared to discharges without COPD (Fig 2
). Further, a diagnosis of COPD was associated with higher age-adjusted in-hospital mortality for pneumonia, hypertension, heart failure, ventilatory failure, and thoracic malignancies when compared to hospital discharges with these comorbidities without a diagnosis of COPD (Fig 3
). A discharge diagnosis of COPD was not associated with higher hospitalization prevalence or in-hospital mortality for acute and chronic renal failure, HIV, GI hemorrhage, and cerebrovascular disease (data not shown). Figure 4
shows the hospitalization prevalence and in-hospital mortality trends for ischemic heart disease, congestive heart failure, and pneumonia in patients discharged with and without COPD.