Association of Metformin Use with Asthma Exacerbation in Patients with Concurrent Asthma and Diabetes: A Systematic Review and Meta-Analysis of Observational Studies
Table 1
Characteristics of the two eligible studies and their participants.
Inclusion criteria: (1) aged ≥18 years with concurrent asthma and diabetes; (2) patients who have had at least one inpatient or two outpatient diagnoses of asthma and diabetes during the enrollment period; (3) patients who had at least one prescription for asthma and diabetes medication during the enrollment period; (4) matched patients’ date of the asthma and diabetes diagnosis must be earlier than the index date
3 years
Adjusted odds ratio of asthma hospitalization, emergency room visit, and exacerbation
Multivariable logistic regression
Exclusion criteria: (1) patients who had a metformin prescription within 1 year before the index date; (2) patients if they had been diagnosed with COPD, any respiratory tract cancer, or bronchiectasis during the preindex period; (3) patients if they had an asthma-related hospitalization or emergency room visit during the preindex period; (4) patients with invalid or missing information of age, gender, diagnosis codes, medication prescriptions, and enrollment records
Inclusion criteria: (1) adult participants (age 18 or older) with both asthma and diabetes; (2) patients who had at least two compatible outpatient codes or one inpatient code during enrollment; (3) qualifying outpatient claims to be within one year
6 years
Adjusted odds ratio of asthma hospitalization, emergency room visit, exacerbation, and corticosteroid use
Cox proportional hazards model
Exclusion criteria: (1) individuals with any diagnosis of chronic obstructive pulmonary disease, bronchiectasis, or interstitial lung disease; (2) those with a contraindication for metformin use, type I diabetes, and a rheumatologic condition that may require systemic corticosteroids for symptoms unrelated to asthma