COPD exacerbations associated with the modified Medical Research Council scale and COPD assessment test among Humana Medicare members

Abstract

Background

The Global initiative for chronic Obstructive Lung Disease guidelines recommend assessment of COPD severity, which includes symptomatology using the modified Medical Research Council (mMRC) or COPD assessment test (CAT) score in addition to the degree of airflow obstruction and exacerbation history. While there is great interest in incorporating symptomatology, little is known about how patient reported symptoms are associated with future exacerbations and exacerbation-related costs.

Methods

The mMRC and CAT were mailed to a randomly selected sample of 4,000 Medicare members aged >40 years, diagnosed with COPD (≥2 encounters with International Classification of Dis eases-9th Edition Clinical Modification: 491.xx, 492.xx, 496.xx, ≥30 days apart). The exacerbations and exacerbation-related costs were collected from claims data during 365-day post-survey after exclusion of members lost to follow-up or with cancer, organ transplant, or pregnancy. A logistic regression model estimated the predictive value of exacerbation history and symptomatology on exacerbations during follow-up, and a generalized linear model with log link and gamma distribution estimated the predictive value of exacerbation history and symptomatology on exacerbation-related costs.

Results

Among a total of 1,159 members who returned the survey, a 66% (765) completion rate was observed. Mean (standard deviation) age among survey completers was 72.0 (8.3), 53.7% female and 91.2% white. Odds ratios for having post-index exacerbations were 3.06, 4.55, and 16.28 times for members with 1, 2, and ≥3 pre-index exacerbations, respectively, relative to members with 0 pre-index exacerbations (P<0.001 for all). The odds ratio for high vs low symptoms using CAT was 2.51 (P<0.001). Similarly, exacerbation-related costs were 73% higher with each incremental pre-index exacerbation, and over four fold higher for high-vs low-symptom patients using CAT (each P<0.001). The symptoms using mMRC were not statistically significant in either model (P>0.10).

Conclusion

The patient-reported symptoms contribute important information related to future COPD exacerbations and exacerbation-related costs beyond that explained by exacerbation history.

Keywords:

• Global initiative for chronic Obstructive Lung Disease
• COPD symptomatology
• exacerbations
• exacerbation-related cost
• survey data

Acknowledgments

This manuscript was edited by Mary Costantino, PhD, an employee of Comprehensive Health Insights, Inc., a wholly owned subsidiary of Humana, and funded by Pfizer Inc.

Disclosure

This study was sponsored by Pfizer Inc. MK Pasquale, Y Xu, and CC Davis are employees of Comprehensive Health Insights, Inc., a wholly owned subsidiary of Humana. CL Baker, KH Zou, JG Teeter, TC Lee, and J Bobula are employees and stockholders of Pfizer Inc. AM Renda is an employee of Humana Inc. Comprehensive Health Insights received funding from Pfizer for conducting this study and for the development of this manuscript.