Background
Although lung volume reduction surgery (LVRS) improves survival in appropriately selected patients with Chronic Obstructive Pulmonary Disease (COPD), few procedures are performed. The National Institute for Clinical and Healthcare Excellence recently recommended a more systematic approach to identifying potential candidates. We investigated LVRS referrals from a UK primary care population and aimed to establish an accurate estimate of eligible patients and determine a strategy for identifying potential candidates systematically.

Methods
Clinical Practice Research Datalink (CPRD) GOLD (a primary care database), linked Hospital Episode Statistics (HES) inpatient and Diagnostic Imaging Dataset (DID) were used. COPD patients who had undergone LVRS, patients who met basic eligibility criteria for further screening for LVRS, and patients meeting a more stringent eligibility criteria were identified from April 2012 to September 2015. Thoracic CT, pulmonary rehabilitation status, referral to respiratory outpatient clinics, and AECOPD requiring hospitalisation were compared between actual LVRS recipients and potentially eligible patients.

Results
Among 73,697 COPD patients included, 36 (0.05%) received LVRS, 5,984 (8.1%) met basic eligibility criteria, and 159 (0.2%) met more stringent eligibility criteria. LVRS recipients were younger (mean(SD) age: 64(9.2) years) compared to the stringently eligible patients (69(8.9) years) (p=0.01). Few patients meeting stringent eligibility criteria (6.9%) had a CT thorax in the preceding 3 years or been referred for assessment in secondary care.

Conclusions
A substantial unmet need exists among COPD patients who could potentially benefit from a lung volume reduction procedure but who are not being investigated or referred to consider this possibility.