Factors linked with the risk for CKD in previous research include advanced age, genetics, diabetes mellitus (DM), and hypertension, explained Vivian Yawei Guo, PhD, and colleagues in a paper published in Scientific Reports. “Central obesity, with which excess accumulation of fat occurs in the abdominal area, is also associated with increased risk for CKD,” they wrote. “A previous meta-analysis showed that elevated waist circumference was associated with higher risk for declines in eGFR, an indicator of kidney function that bears great importance in clinical decision-making.”

The investigators added that evidence has suggested a link between high triglyceride levels and risk for CKD. “Due to the close link of central obesity and high triglyceride levels with the risk for CKD, hypertriglyceridemic-waist phenotype (HTGW)—simultaneous presence of central obesity and elevated triglyceride levels— was also found to be linked with renal impairment,” they added. “However, evidence on the association between HTGW and CKD is limited and inconsistent.”

Participants Categorized into Four Phenotypes

Dr. Guo and colleagues explored this association among 7,406 individuals aged45 and older in a cohort setting, followed by a meta-analysis. Participants were categorized into four phenotypes: HTGW, NTNW (normal triglycerides and normal waist circumference), NTGW (isolated enlarged waist circumference), and HTNW (isolated high triglycerides). The team used multivariate logistic regression to determine the association between different phenotypes and risk for CKD. For the meta-analysis, they searched relevant studies from dataset inception through May 1, 2021. A random-effect model was used to estimate the pooled effect and I2 statistic was applied to evaluate heterogeneity.

After 4 years of follow-up, Dr. Guo and colleagues found that 580 (7.8%) participants developed CKD. “Compared to participants who did not develop CKD, those who developed CKD were older, less educated, and more likely to have insufficient physical activity,” they wrote. “Incident CKD cases also tended to have larger waist circumference in females, higher triglycerides and serum creatinine levels, lower eGFR, and higher prevalence of DM, hypertension, and cardiovascular disease, compared to their non-CKD counterparts at baseline.”

HTGW & Increased Risk for CKD

The cumulative incidence rates of CKD throughout 4 years were 6.6%, 8.4%, 7.3%, and 10.9% in the NTNW, NTGW, HTNW, and HTGW groups, respectively. “Compared to the NTNW phenotype, NTGW and HTGW groups had significantly higher risks for CKD,” the researchers wrote. “In contrast, compared to the NTNW group, the risk for CKD was not significantly increased in the group with isolated higher triglyceride levels at follow-up in any of the models (Table).”

Dr. Guo and colleagues noted some limitations in their research. “First, although participants were selected using a multistage probability sampling method, a large proportion was excluded due to missing data or loss of follow-up,” they wrote. “Therefore, the generalizability of our findings might be limited.” Second, they added, as urine samples were not collected, they were unable to define CKD based on albuminuria, which might potentially underestimate the number of CKD cases. Third, evidence has demonstrated a link between CKD and some potential risk factors, such as dietary intake and a sedentary lifestyle. However, due to the lack of relevant information, they were unable to adjust for these factors or exclude the possibility of residual confounders.

“Our findings indicate that in adults aged 45 and older, those with HTGW, or isolated high waist circumference, were at increased risk for developing CKD, compared to those with normal triglyceridemic levels and normal waist circumference,” Dr. Guo and team concluded. “We suggest that simultaneous measurement of triglyceride and waist circumference might be a useful screening tool to identify individuals at high-risk for developing CKD. However, further studies are needed to evaluate the generalizability and cost-effectiveness of such a tool.”