Exfoliation syndrome linked to increased risk of COPD

Exfoliation syndrome (XFS) and chronic obstructive pulmonary disease (COPD) share a similar pathophysiology in elastin repair, extracellular matrix modeling and alterations in pulmonary function possibly involving the LOXL1 gene. In this study, investigators evaluated the potential association between XFS and COPD.

Study design

This analysis included 2,943 patients with XFS, 20,589 patients with COPD and 162 patients with both disorders who were identified from the Utah Population Database within a 20-year window. Controls were selected and matched by gender and age to patients in a 5:1 ratio.

Outcomes

Among XFS patients, the risk of COPD diagnosis was significantly higher than controls (OR 1.4; P<0.0004). This risk was even higher among tobacco users (OR 2.2), confirming a "two-hit" hypothesis with the initial LOXL1 predisposition and subsequent tobacco insult. Interestingly, XFS was associated with longer survival among COPD patients—findings that are somewhat counterintuitive to the underlying hypothesis.

Limitations

The follow-up analysis was not very apparent in the study, including the possibility that controls may have converted into cases. Diagnoses were based on ICD-9 coding, which carry a reduced accuracy due to coding errors. Finally, this was a retrospective analysis with controls matched only on age and gender. The majority of patients in this study were white, limiting the applicability of these findings.

Clinical significance

Patients with XFS who smoke should certainly be advised to consider smoking cessation. These high-risk patients should be followed closely by a primary care provider and/or pulmonologist, as they may be at higher risk of developing COPD.