Investigating Senolytic Properties in Pulmonary Rehabilitation and Metformin in COPD Exacerbations

Inclusion Criteria: * Age 65 and older * History of COPD defined by spirometry demonstrating FEV1/FVC \< 70% * 10 or more tobacco pack year history * History of frequent exacerbations defined as: 1 severe (i.e., COPD hospitalization) or 2 moderate (i.e., outpatient treated exacerbations) in the previous 12 months Exclusion Criteria: * Diabetes or actively being treated with metformin * Metformin allergy * History of lactic acidosis not explained by acute, severe illness * History of low vitamin B12 levels and unwilling to begin standard of care treatment for low vitamin B12 levels * Hepatic…