COPD exacerbations associated with the modified Medical Research Council scale and COPD assessment test among Humana Medicare members.
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.
['Pasquale|Margaret K|MK|', 'Xu|Yihua|Y|', 'Baker|Christine L|CL|', 'Zou|Kelly H|KH|', 'Teeter|John G|JG|', 'Renda|Andrew M|AM|', 'Davis|Cralen C|CC|', 'Lee|Theodore C|TC|', 'Bobula|Joel|J|']
D000368:Aged D015897:Comorbidity D018450:Disease Progression D005260:Female D006801:Humans D008297:Male D006278:Medicare D008875:Middle Aged D017063:Outcome Assessment, Health Care D029424:Pulmonary Disease, Chronic Obstructive D012129:Respiratory Function Tests D012720:Severity of Illness Index D063189:Symptom Assessment D000067251:Symptom Flare Up D014481:United States
exacerbations Global initiative for chronic Obstructive Lung Disease exacerbation-related cost COPD symptomatology survey data