Metformin and all-cause mortality in older adults with type 2 diabetes mellitus and hypertension: NHANES 1999-2018 evidence for albumin as a mediator.

BACKGROUND

Metformin reduces mortality in type 2 diabetes mellitus (T2DM), but its underlying pathways remain incompletely understood. We hypothesize that serum albumin could potentially mediate the effects of metformin on mortality.

METHODS

Participants were drawn from the National Health and Nutrition Examination Survey (NHANES) across ten cycles for this retrospective longitudinal analysis. We employed mediation analysis to assess the impact of metformin on all-cause mortality risk mediated by albumin (ALB).

RESULTS

In our longitudinal study, all-cause mortality was 40.97 %. Multivariate logistic regression analysis identified a significant correlation between metformin and the likelihood of all-cause mortality (HR = 0.8, 95 %CI = 0.71-0.90, P < 0.001). Mediation analysis indicated that the relationship between metformin and all-cause mortality risk was partially mediated by ALB, accounting for 13.32 % of the association (P < 0.0001).

CONCLUSION

ALB mediates the association between metformin use and lower all-cause mortality in older Americans with T2DM and hypertension, underscoring the mortality-reducing importance of nutritional status.