RESUMEN
BACKGROUND: In older patients, frailty and anemia frequently coexist. However, only few studies have been conducted in older patients with multimorbidity and several overlapping causes of anemia, such as inflammation, inadequate nutrition or certain pathologies. This analysis aims to decipher potential factors associated with anemia in older hospital patients with frailty. METHODS: Patients (n=208, age: 62-98 years) were categorized as pre-frail (n=68) and frail (n=140) using the Fried frailty phenotype. We quantified serum concentrations of markers of iron-metabolism (iron, ferritin, transferrin, soluble transferrin receptor, hepcidin), inflammation (interleukin (IL) 6, IL-10 C-reactive protein) and haematology (hemoglobin). Principal component analysis was conducted to evaluate biomarker patterns and associations with frailty were assessed with logistic regression analysis. RESULTS: Anemia prevalence was higher in patients with frailty (84.3% versus 70.6%, p=0.021). Three principal components (PC1-3) were identified. PC1 was characterized by high factor loadings representing inflammation and factor scores differed between patients with pre-frailty and frailty [-0.04 (IQR:1.45) versus -0.51 (IQR:0.87), p<0.001]. PC2 represents macrocytic anemia and thus vitamin B12 or folate deficiency, whereas PC3 indicates hematological pathologies. Only PC1 was associated with frailty status when controlled for age, sex, number of drugs and comorbidities (OR: 2.018, 95%CI: 1.316; 3.094, p=0.001). PC2 and PC3 were not associated with frailty. CONCLUSION: Our results suggest that anemia in patients with frailty is driven by inflammation rather than being disease-related or solely the result of micronutrient deficiencies.