Background: Aspirin is largely used for cardiovascular prevention. While its adverse effect on bleeding is well-documented, the prevalence of anemia remains uncertain. We conducted a meta-analysis on how low-dose aspirin affects hemoglobin and other hematologic parameters in the elderly.
Methods: We systematically searched PubMed, Embase, and Cochrane for studies comparing the hematological parameters and the prevalence of anemia between low-dose aspirin (≤325 mg) and non-aspirin users in individuals aged older than 60 years. We pooled mean differences (MD) for continuous outcomes and odds ratio (OR) for binary outcomes, with 95% confidence intervals (CI), under a random-effects model for both.
Results: Seven studies were included, including three randomized controlled trials (RCTs), totaling 19,792 participants. Among them, 9,771 (49.3%) were treated with aspirin; 55.4% were women and 44% had a history of smoking. There was no significant difference in anemia prevalence (OR 0.85; 95% CI 0.52-1.38; p = 0.50). Mean Corpuscular Hemoglobin (MD 0.06 pg; 95% CI -0.37 to 0.49; p = 0.79), Mean Corpuscular Volume (MD -0.31 fl; 95% CI -1.17 to 0.56; p = 0.49), and hemoglobin concentration (MD -0.02 g/dL; 95% CI -0.26 to 0.21; p = 0.85) between the two groups. However, hemoglobin decline from baseline was higher in aspirin users (MD -0.11 g/dL; 95% CI -0.17 to -0.05; p = 0.0002; I2 = 0%).
Discussion: Our study employs rigorous methodology and a substantial patient cohort, marking the first quantitative meta-analysis in the past decade. Limitations include diverse study designs, short follow-up durations, gender-specific anemia criteria, and insufficient ferritin and iron levels data. Nonetheless, our findings suggest that while low-dose aspirin does not increase anemia prevalence, it is associated with declining hemoglobin levels over time.
Keywords: Anemia; adverse effects; aspirin; elderly; hemoglobin.