C-reactive protein (CRP) levels in people with eating disorders: A systematic review and meta-analysis

Studies suggest that there is a relationship between inflammatory diseases, inflammatory markers such as C-reactive protein (CRP) and psychiatric disorders. In eating disorders, cross-sectional studies have recently examined peripheral CRP levels in blood serum and plasma, which allow a comprehensive meta-analysis. This systematic review and meta-analysis examined studies from three databases, measuring CRP levels in people with eating disorders, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. A total n = 14 publications were included into the systematic review. Of these, n = 13 cross-sectional papers with N = 700 participants were meta-analysed, n = 11 in anorexia nervosa (AN) and n = 2 in binge eating disorder (BED). One study of the total n = 14 was narratively summarised because it was not suitable for inclusion into the meta-analysis. In the cross-sectional analyses, CRP levels were significantly lower in people with AN compared to health controls (HCs), but CRP level were higher in people with BED compared to HCs. Patients with AN appear to have lower CRP levels compared to healthy controls. This could be a result of malnutrition or specific nutritional deficiencies. Due to the reduced CRP levels in AN, patients might be at risk for bacterial infections or developing autoimmune diseases, and clinicians might fail to notice an inflammatory process or an infection. In contrast, patients with BED were found to have higher CRP level than healthy controls which might be a consequence of an inflammatory response triggered by overeating, disordered eating patterns and the consumption of low-quality food during binges.