Nontuberculous mycobacterial lung disease (NTMLD) in patients with chronic obstructive pulmonary disease (COPD) is associated with a substantial incremental mortality burden, according to study findings published in BMC Infectious Diseases.
Due to shared common nonspecific symptoms (cough, phlegm, fatigue, dyspnea) in NTMLD, COPD, and other respiratory diseases, NTMLD may escape the notice of health care providers, resulting in delayed diagnosis and potentially leading to disease progression and poor clinical outcomes. Investigators therefore assessed older adults with COPD to evaluate the risk of incremental mortality associated with NTMLD.
This retrospective cohort study used ICD-9 and -10 codes in the US Medicare claims database from 2010 to 2017 to identify 4926 patients with preexisting COPD and NTMLD, who were subsequently matched 1:3 by sex (54.4% women) and age (at least 65 years; mean [SD] age, 76.7 [6.7] years) with patients with COPD without NTMLD (control cohort; n=14,778). The majority of patients in both groups were White (NTMLD/COPD cohort, 91.4%; control cohort, 89.0%). Follow-up was from index (first medical claim with diagnosis of NTMLD) through December 2017 or until death. In all participants, COPD was diagnosed prior to the first NTMLD diagnosis, and the first NTMLD diagnosis was between 2011 and 2016.
A higher proportion of patients with NTMLD/COPD vs patients with COPD only had nonpulmonary comorbid conditions including underweight or abnormal weight loss (21.9% vs 6.0%), reflux (41.1% vs 29.0%), and rheumatoid arthritis (6.9% vs 4.3%). A lower proportion of patients with NTMLD/COPD vs patients with COPD only had nonpulmonary comorbid conditions including diabetes, and overweight and obesity.
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The substantial incremental mortality burden associated with NTMLD in patients with COPD highlights the importance of developing interventions targeting this high-risk group and may indicate an unmet need for timely and appropriate management of NTMLD.
Patients with NTMLD/COPD vs patients with COPD only had a higher proportion of pulmonary symptoms (cough, 63.0% vs 24.4%; emphysema, 39.0% vs 10.3%; pneumonia, 58.5% vs 12.2%; dyspnea, 72.7% vs 37.6%; all P <.0001).
A higher proportion of deaths occurred in the NTMLD/COPD cohort vs the control cohort (41.5% vs 26.7%); patients with NTMLD/COPD had a shorter time to death as well as higher unadjusted annual mortality rates (158.5 vs 86.0 deaths/1000 person-years) (all P <.0001), in univariate analyses.
Multivariate analyses (controlling for sex, age, selected comorbidities, COPD severity) showed a similar increased mortality risk. Patients with COPD and NTMLD had higher mortality rates (rate ratio, 1.36; 95% CI, 1.28-1.45), higher hazard of death (hazard ratio, 1.37; 95% CI, 1.28-1.46), and were more likely to die (odds ratio, 1.39; 95% CI, 1.27-1.51) (all P <.0001).
Study limitations include the retrospective design, coding errors, and the lack of pharmacotherapy data to confirm validity of the COPD population.
“The substantial incremental mortality burden associated with NTMLD in patients with COPD highlights the importance of developing interventions targeting this high-risk group and may indicate an unmet need for timely and appropriate management of NTMLD,” the study authors concluded.
Disclosure: This research was supported by Insmed Incorporated (Bridgewater, NJ). Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
