Non‐Dipping Blood Pressure and Reduced Heart Rate Deceleration Capacities Are Associated With Malnutrition in Patients With Gastrointestinal Cancer

Abnormal blood pressure rhythm and decreased heart rate variability are both associated with poor prognosis. However, there are few studies on the relationship between these factors and malnutrition. This study aimed to investigate the characteristics of blood pressure and heart rate variability in malnourished individuals with gastrointestinal cancer. We collected ambulatory blood pressure and heart rate variability data from 662 patients with gastrointestinal tumors at Guangxi Medical University Cancer Hospital in 2023. The Controlling Nutritional Status index (CONUT) was used as a malnutrition indicator, and CONUT < 2 was defined as malnutrition. The characteristics of blood pressure and heart rate variability and their relationship with malnutrition were analyzed. A significant association was found between malnutrition and blood pressure dipping patterns (p = 0.003). Deceleration capacity (DC) [OR (95% CI): 0.724 (0.628-0.835), p < 0.001] and NPDR [OR (95% CI): 0.951 (0.904-1.001), p = 0.054] was negatively correlated with malnutrition, nighttime average heart rate (nighttime-HR) [OR (95% CI): 1.089 (1.031-1.151), p = 0.002] was positively correlated with malnutrition. DC achieved the highest AUC for malnutrition prediction in the ROC analysis (0.706). Our research indicates that Patients with malnourished gastrointestinal tumors exhibited abnormal circadian rhythms, including blunted nocturnal blood pressure dipping, attenuated heart rate deceleration, and elevated nighttime heart rate. This pattern reflects autonomic dysfunction characterized by impaired vagal activity.