HOUSTON – A common diabetes drug has been shown to improve respiratory outcomes in asthma but its effects on COPD and the combination of asthma and COPD remained unknown.
That’s why a study team led by Baylor College of Medicine and the Michael E. DeBakey VAMC, both in Houston, sought to determine whether metformin could be beneficial for those patients.1
To do that, they categorized 510 participants with COPD (FEV1/FVC < 0.70) in the Genetic Epidemiology of COPD study (COPDGene) as ACO, defined as concurrent physician-diagnosed asthma before age 40 years, or 3,459 with COPD alone.
Researchers estimated the association of baseline metformin use with rate of total and severe respiratory exacerbations during follow-up, The cross-sectional St. George’s Respiratory Questionnaire (SGRQ) score, six-minute walk distance (6MWD), and post-bronchodilator FEV1 percent were used to predict (FEV1pp), and 5-year change in SGRQ, 6MWD, and FEV1pp.
The study team also look at changes in SGRQ, 6MWD and FEV1pp among 108 participants who initiated metformin during follow-up and compared them to 2,080 persistent metformin non-users.
Results among participants with ACO indicated that metformin use was associated with lower rate of total (adjusted incidence rate ratio [aIRR] 0.3; 95% confidence interval [95%CI] 0.11, 0.77) and severe exacerbations (aIRR 0.29; 95%CI 0.10, 0.89).
As for participants with COPD alone, however, no association was determined between metformin use with total (aIRR 0.98; 95%CI 0.62, 1.5) or severe exacerbations (aIRR 1.3; 95% CI 0.68, 2.4) (p-interaction < 0.05).
Still, the study team wrote, metformin use was associated with lower baseline SGRQ score (adjusted mean difference [aMD] – 2.7; 95%CI – 5.3, – 0.2) overall and initiation of the most widely-prescribed diabetes drug was associated with improved SGRQ score (aMD -10.0; 95% CI – 18.7, – 1.2) among participants with ACO but not COPD alone (p-interaction < 0.05). No association between metformin use and 6MWD or FEV1pp was found in any comparison, however.
“Metformin use was associated with fewer respiratory exacerbations and improved quality of life among individuals with ACO but not COPD alone,” the authors concluded. “Results suggest a potential role for metformin in ACO which requires further prospective study.”
- Wu TD, Fawzy A, Kinney GL, Bon J, Neupane M, Tejwani V, Hansel NN, Wise RA, Putcha N, McCormack MC. Metformin use and respiratory outcomes in asthma-COPD overlap. Respir Res. 2021 Feb 26;22(1):70. doi: 10.1186/s12931-021-01658-3. PMID: 33637087; PMCID: PMC7908718.