Supplemental Material for: The association between Metabolic indicators and chronic kidney disease in adults——a cohort analysis

Data were obtained from the 2011 and 2015 waves of the China Health and Retirement Longitudinal Study (CHARLS). Participants with missing data on HGI, WWI, or CKD status, as well as those with pre-existing CKD at baseline, were excluded, leaving a cohort of 3,414 participants free of CKD at baseline who completed follow-up and were included in the analysis of incident CKD. Logistic regression models were used to investigate the longitudinal relationships between baseline HGI and WWI and incident CKD.</p><p dir="ltr">Results: During the 4-year follow-up period (2012–2015), 303 participants (8.9%) developed new-onset CKD.

Results demonstrated a significant association between the HGI and CKD incidence. This positive correlation remained stable after further adjusting for all covariates in Model 3 (OR = 1.27, 95% CI: 1.05–1.53). Subgroup analyses confirmed consistent, robust associations between HGI and CKD across subgroups.

Threshold effect analysis, based on a log-likelihood ratio test, did not reveal a statistically significant non-linear association between HGI and CKD risk (P = 0.422). Furthermore, no significant association was found between WWI and CKD incidence in this study.</p><p dir="ltr">Conclusions: The findings of this study indicate that HGI is significantly positively associated with the risk of developing CKD, suggesting its potential value as a marker for CKD risk stratification.

However, given the observational nature of this study, whether active management of HGI levels can causally reduce CKD incidence warrants further validation through prospective intervention studies.</p>