Association of platelet-to-HDL cholesterol ratio with frailty and all-cause mortality

Abstract Background Frailty often requires intensive care, and the admission outcomes of frail patients are often poor. However, owing to the lack of reliable diagnostic indicators, quickly identifying frailty is challenging. The present study aimed to explore the associations of the platelet/high-density lipoprotein cholesterol ratio (PHR; a novel inflammatory indicator) with frailty and all-cause mortality. Methods The present study analyzed data from the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018. Frailty was assessed on the basis of the 49-item Frailty Index. The associations of the PHR with frailty and long-term survival prognosis were explored through weighted logistic regression, weighted restricted cubic spline (RCS), and weighted Cox regression, with adjustments for demographic factors, lifestyle, blood lipids, medication history, and complications. In addition, subgroup and interaction analyses were conducted. Finally, several sensitivity analyses were performed. Results A total of 15,615 adult participants were included, with 7,928 women (53.63%) and an average age of 60.76 years. After fully adjusting for confounding variables, the prevalence of frailty in the highest PHR quartile group of was significantly greater than that in the lowest quartile group (OR: 1.23, 95% CI: 1.04–1.47; P = 0.02). The RCS showed that the inflection point was 166.7. Before and after the inflection point, the PHR was negatively associated (OR: 0.88, 95% CI: 0.80–0.97, P = 0.01) and positively associated (OR: 1.10, 95% CI: 1.02–1.19, P = 0.01) with frailty, respectively. Subgroup analysis suggested that the association between PHR and frailty was stronger in women than in men. A total of 5,544 frail participants were included in the survival analysis. The RCS revealed that the PHR was associated with the all-cause mortality risk of frail participants in a U-shaped manner, with an inflection point of 240.4. Before and after the inflection point, the PHR decreased (HR: 0.89, 95% CI: 0.81–0.97, P = 0.01) and the all-cause mortality risk increased (HR: 1.08, 95% CI: 1.02–1.14, P = 0.01), respectively. Conclusion The present study suggests that there is a J-shaped association between PHR and frailty in the adult population of the United States and that the association between the PHR and frailty is stronger in women. In addition, the PHR has a U-shaped relationship with the all-cause mortality risk of frail patients.