Summary
Dr. Bob Centor interviews hematologist Dr. Zoe McQuilton about her secondary analysis of the ASPREE trial examining how daily low-dose aspirin affects iron status and anemia risk in elderly patients. The ASPREE trial enrolled over 19,000 healthy adults aged 70+ and found that aspirin did not improve disability-free survival but increased major bleeding. McQuilton's analysis revealed that aspirin users had a 20% higher incidence of anemia over five years (23.5% vs 20% in placebo) and significantly greater declines in both hemoglobin and ferritin levels. The effect persisted even after accounting for major bleeding events, suggesting that low-grade occult GI bleeding drives progressive iron depletion. The findings add another harm to consider when evaluating aspirin for primary prevention and raise concerns about monitoring iron status in patients on aspirin for secondary prevention.
Key Points
- The ASPREE trial of 19,000+ healthy elderly found aspirin did not prolong disability-free survival but increased major bleeding
- By year five, 23.5% of aspirin users developed anemia versus 20% on placebo, a 20% relative increase
- Ferritin levels declined 11.5% more in aspirin users, with 13% vs 9.8% developing iron deficiency (ferritin <45)
- The anemia effect persisted even after excluding major bleeding events, suggesting subclinical occult GI blood loss
- Hemoglobin declined progressively over five years in all participants but faster in the aspirin group
- These findings add to the harms column when weighing aspirin for primary cardiovascular prevention
- Iron status monitoring may be warranted even in secondary prevention patients taking aspirin long-term
Key Moments
ASPREE Trial Shows Aspirin Increases Anemia Risk by 20%
Dr. McQuilton presents the key finding that aspirin increased the five-year risk of developing anemia by approximately 20%, with a steeper decline in hemoglobin levels compared to placebo.
"the risk of developing anemia by five years was approximately 20% in the placebo group compared to approximately 23.5% in the aspirin group. And so that resulted in an increased rate of developing anemia in aspirin by approximately 20%"
Aspirin Depletes Iron Stores Through Occult Bleeding
Ferritin levels dropped significantly more in aspirin users, with 13% vs 9.8% developing iron deficiency, likely caused by low-grade subclinical GI bleeding.
"looking at ferritin at a cutoff of 45 milligrams per litre there was a higher proportion of participants in the aspirin group who met that definition of iron deficiency so 13% in the aspirin group compared to 9.8% in placebo"
Adding to the Harms of Aspirin in Primary Prevention
The researchers conclude that iron depletion and anemia represent additional harms to weigh against aspirin's diminishing benefits in primary prevention settings.
"this subsequent analysis we've done, I think, just adds to the potential harms from aspirin in the setting of primary prevention with increasing risk of anemia and iron deficiency"
