Renal Function Effect on the Association Between Body Mass Index and Mortality Risk After Acute Myocardial Infarction

Clinical implications of changes in metabolic syndrome status after kidney transplantation: a nationwide prospective cohort study

BACKGROUND

Metabolic syndrome (MetS) is prevalent in patients with end-stage kidney disease, and kidney transplantation is expected to modify the metabolic status. However, whether changes in metabolic status at the time of transplantation affect recipient outcomes remains unclear.

METHODS

We analyzed 4187 recipients registered in a nationwide prospective cohort from 2014 to 2020. MetS was defined as the presence of three or more components of the metabolic syndrome. Patients were classified based on the pre- and post-transplant MetS status: MetS-free, MetS-developed, MetS-recovered and MetS-persistent. Study outcomes were occurrence of death-censored graft loss and a composite of cardiovascular events and death.

RESULTS

Among recipients without pre-transplant MetS, 19.6% (419/2135) developed post-transplant MetS, and MetS disappeared in 38.7% (794/2052) of the recipients with pre-transplant MetS. Among the four groups, the MetS-developed group showed the worst graft survival rate, and the MetS-persistent group had a poorer composite event-free survival rate. Compared with the MetS-free group, the MetS-developed group was associated with an increased risk of graft loss [adjusted hazard ratio (aHR) 2.35; 95% confidence interval (CI) 1.17-4.98] and the risk of graft loss increased with increasing numbers of dysfunctional MetS components. MetS-persistent was associated with increased risks of cardiovascular events and death (aHR 2.46; 95% CI 1.12-5.63), but changes in the number of dysfunctional MetS components was not.

CONCLUSION

Kidney transplantation significantly alters the metabolic status. Newly developed MetS after transplantation was associated with an increased risk of graft loss, whereas persistent MetS exposure before and after transplantation was associated with increased risks cardiovascular events and patient survival.

Impact of body mass index on in-hospital mortality in older patients hospitalized for bacterial pneumonia with non-dialysis-dependent chronic kidney disease

BACKGROUND

Low body mass index (BMI) in older individuals with decreased kidney function is important because of its association with poor prognosis and frailty. Herein, we aimed to clarify the association between BMI and in-hospital mortality among older patients with non-dialysis-dependent chronic kidney disease (CKD) stratified by kidney function.

METHODS

Using data from the Medical Vision Database, this multicentre cohort study included people aged ≥ 60 years with an estimated glomerular filtration rate of < 60 ml/min/1.73 m² but without dialysis dependency, hospitalised for bacterial pneumonia during 2014-2019. We compared the risk of in-hospital death between patients with BMI categories based on the quartiles (low, medium-low, medium-high, and high) setting medium-high BMI as a reference. We further assessed the association with BMI using a cubic spline, setting BMI as a nonlinear continuous variable and a BMI of 22 kg/m² as a reference. We also evaluated the association between BMI and kidney function using a generalised additive model adjusted for interaction terms between nonlinear continuous BMI and kidney function.

RESULTS

We obtained data for 3,952 patients, with 350 (8.9%) in-hospital deaths. When compared with medium-high BMI, low BMI was associated with an increased risk of death and longer hospital stay, whereas the other two categories were comparable. Models using a cubic spline showing an association between BMI and in-hospital death showed an L-shaped curve; BMI < 22.0 kg/m² was associated with an increased risk for mortality, and at a BMI of 18.5 kg/m², the odds ratio was 1.43 with a 95% confidence interval of 1.26-1.61 when compared with a BMI of 22.0 kg/m². Analysis of the interactive effects of kidney function using the generalised additive model showed that a protective association of high BMI tapered along with decreased kidney function.

CONCLUSIONS

This cohort study suggests not only that lower BMI and low kidney function are associated with in-hospital mortality independently but also that the protective effects of high BMI weaken as kidney function decreases via the analysis of the interaction terms. This study highlights the necessity for the prevention of underweight and demonstrates the interaction between BMI and kidney function in older patients with non-dialysis-dependent CKD.

BMI Modifies Increased Mortality Risk of Post-PCI STEMI Patients with AKI

Mortality from acute ST elevation myocardial infarction (STEMI) was significantly reduced with the introduction of percutaneous catheterization intervention (PCI) but remains high in patients who develop acute kidney injury (AKI). Previous studies found overweight to be protective from mortality in patients suffering from STEMI and AKI separately but not as they occur concurrently. This study aimed to establish the relationship between AKI and mortality in STEMI patients after PCI and whether body mass index (BMI) has a protective impact. Between January 2008 and June 2016, two thousand one hundred and forty-one patients with STEMI underwent PCI and were admitted to the Tel Aviv Medical Center Cardiac Intensive Care Unit. Their demographic, laboratory, and clinical data were collected and analyzed. We compared all-cause mortality in patients who developed AKI after PCI for STEMI and those who did not. In total, 178 patients (10%) developed AKI and had higher mortality (p < 0.001). Logistic regression analysis was performed to determine the relationship between AKI, BMI, and mortality. AKI was significantly associated with both 30-day and overall mortality, while BMI had a significant protective effect. Survival analysis found a significant difference in 30-day and overall survival between patients with and without AKI with a significant protective effect of BMI on survival at 30 days. AKI presents a major risk for mortality and poor survival after PCI for STEMI, yet a beneficial effect of increased BMI modifies it.