Study supports continued metformin use in T2D patients with advanced kidney disease

For patients with type 2 diabetes (T2D) and chronic kidney disease (CKD), continued use of metformin for at least 6 months when eGFR falls below 30 mL/min/1.73m² appears to yield a small but significant decrease in all-cause mortality, according to a nationwide observational cohort study.

Researchers looked at 371,742 Scottish residents with T2D, of which 4,278 (median age 77.0 years, 51 percent women) were identified as prevalent metformin users with incident CKD stage 4 and were included in the analysis. The median eGFR at baseline was 27 mL/min/1.73m², and cardiovascular comorbidities were common, with 38.4 percent having ischaemic heart disease and 10.7 percent having cerebrovascular diseases.

All-cause mortality was the primary outcome. Major adverse cardiovascular events (MACE) were also assessed as the secondary outcome. Target trial emulation with clone-censor-weight design and marginal structural models were used in the analyses.

Within 6 months of developing CKD stage 4, 1,713 (40.1 percent) individuals discontinued metformin use. Compared with continued treatment with metformin, discontinuation was associated with reduced 3-year survival (63.7 percent vs 70.5 percent; hazard ratio [HR], 1.26, 95 percent confidence interval [CI], 1.10–1.44). Meanwhile, the incidence of MACE did not differ between the two treatment strategies (HR, 1.05, 95 percent CI, 0.88–1.26).

Analysis using marginal structural models yielded the same results. Patients who continued vs stopped metformin had increased risk of all-cause mortality (HR, 1.34, 95 percent CI, 1.08–1.67) but similar risk of MACE (HR, 1.04, 95 percent CI, 0.81–1.33).