Interactive effects of intrinsic capacity and obesity on the risk of chronic kidney disease in older patients with type 2 diabetes mellitus

Background: Intrinsic capacity (IC) is a novel concept focusing on normal and healthy aging. The effect of IC on the risk of chronic kidney disease (CKD) in older type 2 diabetes mellitus (T2DM) patients has rarely been studied. We investigated whether a decline in IC is associated with the risk of CKD. Methods: This is a cross-sectional study. A total of 2482 older subjects with T2DM managed through a disease care program were enrolled. The five domains of IC, namely locomotion, cognition, vitality, sensory, and psychological capacity were assessed. Based on these domains, the IC composite score was calculated. CKD risk was classified according to the KDIGO 2012 CKD definition. Univariate and multivariate analyses were used to assess the association between IC score and CKD risk. Results: The risk of CKD increased in parallel with IC score (p for trend<0.0001). In multivariate analysis, compared to those with an IC score 0, the odds ratio of having a moderately increased and very high risk stage of CKD was 1.76 (1.31-2.37) times higher for those with an IC score of 2-5. Furthermore, an increased IC score was associated with a higher prevalence of moderate and severe obesity. Moreover, there was a synergistic interaction between IC score and obesity on the risk of CKD (synergy index=1.683; 95% CI: 0.630-3.628), and the proportion of the CKD risk caused by this interaction was 25.6% (attributable proportion of interaction=0.256). Conclusions: Our findings indicate that IC score may be closely related to the risk of CKD. In addition, there may be a synergistic interaction between IC score and obesity, and this synergistic interaction may increase the risk of CKD.