Abstract
Background and Aims
Obesity is a risk factor for chronic kidney disease (CKD), but the effect of reducing body mass index (BMI) on the prevention of CKD is controversial. One of reasons for this disagreement is that part of patients with a BMI decrease may have an unfavourable health status. In such cases, the BMI decrease could be a risk factor for the development of CKD. Therefore, by analysing the data of annual health check-ups, we examined an association between BMI change and CKD development to determine whether BMI reduction helps prevent CKD development.
Method
We analysed the data of 6,959 subjects who underwent annual health check-ups in both 2013 and 2018. By a multivariate logistic regression analysis, we investigated a relationship between BMI change and CKD development within the 5 years between 2013 and 2018. The percent change in the BMI (ΔBMI) was calculated using the following equation: {(BMI in 2018 − BMI in 2013)/BMI in 2013} ×100. For analyses, we classified the subjects into five groups based on their ΔBMI value: (i) severe BMI decrease (ΔBMI <−2.5%); (ii) moderate BMI decrease (ΔBMI ≥−2.5% but <0%); (iii) maintained BMI (ΔBMI ≥0% but <2.5%); (iv) moderate BMI increase (ΔBMI ≥2.5% but <5%); (v) severe BMI increase (ΔBMI ≥5%). For further analysis, we divided the subjects into non-obesity category (basal BMI <25 Kg/m2) and obesity category (basal BMI ≥25 Kg/m2). Subjects with an estimated glomerular filtration rate <60 mL/min./1.73 m2 were defined as having a CKD.
Results
After adjusting several covariates, compared with the maintained BMI group, the severe BMI decrease group showed a significantly low risk of CKD development (odds ratio (OR) 0.70, 95% confidence intervals (CI) 0.54-0.91, p <0.01) and the severe BMI increase group had a significantly high risk (OR 1.40, CI 1.08-1.81, p = 0.01). A farther analysis revealed that the OR of CKD development for the severe BMI increase group in the obesity category was higher than that in the non-obesity category (OR 1.75 vs. 1.29).
Conclusion
In subjects who underwent annual health check-ups, BMI reduction had a significant effect on the prevention of CKD development, whereas an increase in the BMI was a risk factor for CKD development. Moreover, by severe increase in the BMI, obesity subjects showed higher risk of CKD development than non-obesity subjects.
Elevated body mass index as a risk factor for chronic kidney disease: current perspectives
