Malnutrition Reverses Obesity Survival Advantage in Hospitalized Patients With End Stage Kidney Disease

Malnutrition coexisting with obesity in patients with end-stage kidney disease (ESKD) undergoing maintenance dialysis may reverse the survival advantage observed in the “obesity paradox” among patients with chronic disease, according to new research.1

The findings highlight increased mortality, adverse clinical outcomes, longer hospital length of stay, and higher costs among patients with malnourished obesity compared with non-malnourished patients within this study population.1

“Our findings show that obesity is significantly associated with lower in-hospital mortality among ESKD patients without malnutrition,” wrote study investigator Charat Thongprayoon, MD, an associate professor of medicine at Mayo Clinic, and colleagues. “However, when malnutrition coexists, this survival advantage is reversed, underscoring the importance of detecting malnutrition in obese ESKD patients.”1

Globally, approximately 2.5 million individuals with ESKD are at increased risk of hospitalization and mortality, with nutritional imbalance considered one of the most critical risk factors for disease complications. Conversely, hospitalization for any illness among patients with ESKD increases susceptibility to malnutrition. Although malnutrition is commonly associated with undernutrition, the World Health Organization has noted malnutrition also occurs in overweight and obese individuals.1,2

The “obesity paradox” in chronic disease, including ESKD, describes improved survival outcomes among patients with a body mass index (BMI) ≥30 compared with non-obese individuals. Prior evidence suggests protective effects from increased muscle mass and total body fat. However, the coexistence of obesity and malnutrition, and their combined impact on clinical outcomes, among hospitalized patients with ESKD receiving maintenance dialysis has remained unclear.1,2

To address this gap, Thongprayoon and colleagues conducted a national database study using US regional and national estimates of inpatient utilization, access, charges, quality, and outcomes from the National Inpatient Sample (NIS). Investigators identified malnutrition and obesity using ICD-10 codes. Study outcomes included hospital mortality, adverse clinical events, inpatient treatments, and resource utilization, including costs and length of stay.1

“To our knowledge, this is the first and largest nationally representative study to examine comprehensive in-hospital outcomes, treatments, and healthcare resource utilization among dialysis patients,” wrote investigators.1

The analysis included 674,367 hospitalized adults with ESKD receiving hemodialysis (HD) or peritoneal dialysis (PD) as their maintenance modality. Overall, 125,978 patients had obesity (18.7%). Among these, 119,155 patients were not malnourished (94.6%), while 6823 had malnutrition (5.4%).1

Investigators reported an overall in-hospital mortality rate of 4.6%, with higher mortality among patients with malnourished obesity (9.8%) and lower mortality among patients with non-malnourished obesity (3.6%) compared with non-obese patients (4.7%; all P <.001). In adjusted analyses, investigators found malnourished obesity was independently associated with an increased risk of in-hospital death (OR, 2.08). Conversely, investigators reported non-malnourished obesity was associated with a reduced risk of in-hospital mortality (OR, 0.87).1

For adverse clinical outcomes, investigators linked malnourished obesity to increased risks of sepsis (OR, 2.63) and catheter-related bloodstream infection (OR, 1.70), but a decreased risk of volume overload (OR, 0.91). In contrast, investigators observed non-malnourished obesity was associated with elevated risks for all assessed adverse outcomes, including sepsis (OR, 1.07), catheter-related bloodstream infection (OR, 1.09), and volume overload (OR, 1.08).1

Regarding inpatient treatments, investigators found malnourished obesity was associated with increased risks of vasopressor use (OR, 2.56), total parenteral nutrition (OR, 4.36), mechanical ventilation (OR, 1.95), and blood transfusion (OR, 1.60). Investigators also reported non-malnourished obesity was associated with lower risks of total parenteral nutrition (OR, 0.57) and blood transfusion (OR, 0.89), but higher risks of vasopressor use (OR, 1.06) and mechanical ventilation (OR, 1.85) compared with non-obese patients.1

Investigators further observed patients with malnourished obesity experienced significantly longer hospital stays by 7.14 days and higher hospitalization costs by $99514 compared with patients without obesity. Similarly, investigators found patients with non-malnourished obesity had a longer length of stay by 0.14 days and higher hospitalization costs by $2811 compared with non-obese patients.1

In multivariable analyses, investigators reported no significant interaction between malnutrition or obesity status and dialysis modality for in-hospital outcomes, including mortality, sepsis, catheter-related bloodstream infection, or the use of vasopressors, total parenteral nutrition, or blood transfusions (all P for interaction >.05).1

However, investigators observed malnourished obesity was associated with a reduced risk of volume overload among patients receiving hemodialysis (OR, 0.89), but not among those receiving peritoneal dialysis (OR, 1.37). Investigators also found patients receiving hemodialysis had an increased need for mechanical ventilation, longer hospital stays, and higher hospitalization costs than those receiving peritoneal dialysis (all P for interaction <.05).1

References

1. Wathanavasin W, Kaewput W, Thongprayoon C, Tangpanithandee S, Suppadungsuk S, Cheungpasitporn W. Association of Obesity and Malnutrition with In-Hospital Mortality and Clinical Outcomes in Patients Receiving Maintenance Dialysis: A National Database Study. Nutrients. 2026;18(1):157. doi:https://doi.org/10.3390/nu18010157

2. ‌Filipska A, Bohdan B, Wieczorek PP, Hudz N. Chronic kidney disease and dialysis therapy: incidence and prevalence in the world. Pharmacia. 2021;68(2):463-470. doi:https://doi.org/10.3897/pharmacia.68.e65501