Patients with chronic kidney disease and high body mass index (BMI) fluctuations are at an increased risk of death, myocardial infarction, stroke, and increased chance of requiring kidney replacement therapy. 

It has been shown earlier that BMI changes or metabolic parameters are linked with an increased risk for heart disease in the general population. However, in a retrospective study, the significance remained both in those with an increasing trend of BMI and in those with a decreasing trend. This brings out the importance of unstable metabolic status, which may be crucial than obesity or increasing BMI, despite the fact that a higher BMI is one of the most acknowledged bad metabolic health statuses in the general population. 

Metabolic syndrome components fluctuations are linked with the prognosis of patients with CKD, not on dialysis. Those who have a higher number of metabolic syndrome components with higher BMI variability had a worse prognosis. 

While it has been demonstrated that bariatric surgery improves metabolic parameters, it is crucial to further assess the impact of large reduction in weight among patients with CKD on their risk for CVD, which is the leading cause of mortality in this patient population. 

Reference:

1. Sehoon P, Semin C, Soojin L, et al. The prognostic significance of body mass index and metabolic parameter variabilities in predialysis chronic kidney disease: A nationwide observational cohort study. J Am Soc Nephrology. Published online August 12, 2021. DOI: 10.1681/ASN.2020121694
2. Kyoung Kim M, Han K, Park YM, et al. Associations of variability in blood pressure, glucose and cholesterol concentrations, and body mass index with mortality and cardiovascular outcomes in the general population. Circulation. 2018;138:2627-2637.