Comorbidities, repeated hospitalizations, and age ≥ 80 years as indicators of anemia development in the older population.

Anemia represents a common condition among the elderly; however, its prevalence and causes are not well known. This retrospective analysis was performed on 981 patients aged ≥ 60 in Poland over 2013-2014. The prevalence of anemia was 17.2% and increased with age. The predominant causes of anemia were the following: anemia of chronic disease (33.1%), unexplained anemia (28.4%), deficiency anemia (22.5%, including iron deficiency 13%), and chemo-/radiotherapy-induced anemia (8.9%). In the multivariate logistic regression model, factors increasing the risk of anemia were the following: age ≥ 80 years (OR 2.29; 95%CI 1.19-4.42; P = 0.013), the number of comorbidities (two diseases OR 2.85; 95%CI 1.12-7.30; P = 0.029, three diseases OR 6.28; 95%CI 2.22-17.76; P = 0.001, four diseases OR 4.64; 95%CI 1.27-17.01; P = 0.021), and hospitalizations (OR 1.34; 95%CI 1.13-1.58; P = 0.001). After a 2-year follow-up, the cumulative survival among patients without anemia in relation to the group with anemia was 90.76 vs. 78.08% (P < 0.001). In the multivariate model, anemia (HR 3.33, 95%CI 1.43-7.74, P = 0.005), heart failure (HR 2.94, 95%CI 1.33-6.50, P = 0.008), and cancer (HR 3.31, 95%CI 1.47-7.49, P < 0.004) were all significantly correlated with mortality. In patients ≥ 60 years, the incidence of anemia increases with age, number of comorbidities, and frequency of hospitalizations and has an adverse impact on survival.