AN INTEGRATED SIMULATION MODEL OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE

Purpose: We describe an evaluation tool for cost-benefit analyses of population-level smoking and respiratory health interventions, focusing on chronic obstructive pulmonary disease (COPD). 

Method: We constructed a general purpose simulation model of COPD. The model simulates populations composed of individuals, with physiology simulated as continuous-time trajectories, and acute symptoms and healthcare utilization simulated as discrete events in time. Pulmonary function measures, namely FEV­­₁ and FVC, are modeled based on combined analysis of spirometric data from the National Health and Nutrition Examination Study (NHANES) and the Lung Health Study (LHS). Acute exacerbations and resulting healthcare utilization models are anchored by analyses of the National Hospital Discharge Survey (NHDS), National Hospital Ambulatory Medical Care Survey (NHAMCS), and National Ambulatory Medical Care Survey (NAMCS), and resolved for individual-level risk factors using published reports of COPD-focused clinical trials. Symptom onset, COPD diagnosis, patterns of medication use, and medication effects are modeled based on meta-analyses of clinical trial reports. Simulated individuals are initialized to match patient characteristics of individuals from NHANES. In order to express associations between COPD and cardiovascular disease, stroke, lung cancer, and overall mortality risk, the COPD model is integrated as a component of the broader Archimedes Model.

Result: We demonstrate that, at a population level relative to other studies of the U.S. population, our integrated model accurately replicates pulmonary function distributions, treated acute exacerbation rates, COPD-related hospitalization rates, and co-occurrence of COPD with cardiovascular disease, stroke, lung cancer, and overall risk of mortality. 

Conclusion: The Archimedes Model, with the inclusion of COPD, provides a comprehensive framework for evidence-based evaluations of smoking cessation therapy relative to other population-level intervention programs.