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Lung function after randomization to metformin, lifestyle intervention or placebo in the Diabetes Prevention Program Outcomes Study (DPPOS)

Pistenmaa CL, Doherty L, Hermann EA, Brown AL, Dabelea D, Holguin F, Watson K, Knowler WC et al.

Respiratory medicine, 2026

3,234 participants

Abstract

Introduction: Metformin and physical activity have been suggested as beneficial for chronic lung disease; however, there are no prior randomized trials.

Methods: The Diabetes Prevention Program (DPP) was a 3-year trial that randomized 3234 individuals at risk for diabetes to metformin, lifestyle intervention or placebo. After the DPP, 88% of participants enrolled in the DPP Outcomes Study that offered lifestyle intervention to all and open-label continuation of metformin. Spirometry was performed at approximately 19 and 22 years post-randomization. Lung function measures were compared in an intention-to-treat (ITT) analysis by original randomization group. Models were unadjusted and adjusted for demographics, body size, smoking and sitting/standing at spirometry. Additional analyses tested prevalence of obstruction (FEV1/FVC 1/FVC ≥70%), preserved ratio impaired spirometry (PRISm: FEV1 1/FVC ≥70%) and symptoms (COPD Assessment Test [CAT] score ≥10).

Results: The 1888 participants with spirometry were a mean (±SD) age of 68.2 ± 9.3 years, 70% female and 6% currently smoked and 33% had previously smoked cigarettes. Mean follow-up time was 19.0 ± 0.8 years. The mean FEV1 was 2.14 ± 0.60 L, FVC 2.74 ± 0.74 L, FEV1/FVC 78.4 ± 6.4%, mean BMI was 32.4 ± 6.7 kg/m2 and 58% had diabetes. In both unadjusted and adjusted ITT analyses, randomization group was not associated with FEV1, FVC or FEV1/FVC. Likewise, rates of obstruction, restrictive pattern, PRISm or symptoms did not differ…

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 3,234 participants or records.

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