The association between serum albumin and alkaline phosphatase in cancer patients

The role of serum albumin (ALB) has been extensively studied in patients with cancer; however, research on its effect on bone metastasis in these patients remains limited. This study aimed to investigate the relationship between serum ALB and alkaline phosphatase (ALP) levels in patients with tumors. Using data from the National Health and Nutrition Examination Survey 2011 to 2018, we assessed the correlation between serum ALB and ALP levels using a weighted multivariate linear regression model, whereas a weighted generalized additive model and smooth curve fitting were used to address potential nonlinearities. A total of 1876 patients with cancer were included in our study. In the subgroup analysis stratified by sex, race/ethnicity, and liver disease, the negative correlation of ALB with ALP remained for most groups, except in blacks (β = -1.755, 95%CI: [-3.848, 0.338], P = .103) and patients with gout (β = -0.676, 95%CI: [-2.061, 0.709], P = .340). In black people and patients with gout, the relationship between ALB and ALP showed an inverted U-shaped curve, with an inflection point at approximately 42 g/dL. Our study showed an inverse correlation between ALB and ALP levels in most patients with tumors, but not in black patients and those with gout. The measurement of ALB levels can serve as a screening tool for bone metastases while guiding therapeutic intervention strategies.