Admission for COPD Exacerbation Is Associated with the Clinical Diagnosis of Pulmonary Hypertension: Results from a Retrospective Longitudinal Study of a Veteran Population

Patients with chronic obstructive pulmonary disease and pulmonary hypertension (PH–COPD) have an increased risk of hospitalizations and death compared to COPD alone. Identifying PH in COPD is challenging because performing right heart catheterization, the gold standard for PH diagnosis, is invasive and not routinely performed. Clinical characterization of COPD patients at risk who are progressing toward PH will aid therapeutic development at earlier stages of progressively fatal PH–COPD. We studied the records of 5,45,086 patients in a large Veterans Affairs healthcare network (2000–2012) with a primary discharge diagnosis of COPD based on encounters' ICD-9 codes and further stratified into those who received an additional ICD-9 code for a PH diagnosis. Patients with PH–COPD were assigned to one of the four subgroups: those with (a) no history of exacerbation or hospital admissions, (b) history of exacerbations but no hospital admissions, (c) hospital admissions unrelated to COPD and (d) history of COPD exacerbation-related hospital admissions. We also examined the COPD and COPD-PH cohorts for associated comorbidities such as cardiac disease and the presence of obstructive sleep apnea (OSA). A regression analysis revealed that patients with COPD exacerbation-related hospital admissions had 7 × higher risk of having a concomitant clinical diagnosis of PH compared to non-hospitalized patients. COPD-PH patients had higher rates of cardiac comorbidities (89% vs. 66%) and OSA (34% vs. 16%) compared to COPD alone. We conclude that COPD patients hospitalized for COPD exacerbations are at a higher risk for developing PH, and hospitalized COPD patients with cardiac comorbidities and/or OSA should be screened as at-risk population for developing PH.