WEDNESDAY, Aug. 10 (HealthDay News) -- Increased blood loss from diagnostic phlebotomy increases the risk for moderate to severe hospital-acquired anemia (HAA) among patients with acute myocardial infarction (AMI), according to a study published online Aug. 8 in the Archives of Internal Medicine.
Adam C. Salisbury, M.D., from Saint Luke's Mid America Heart and Vascular Institute in Kansas City, Mo., and colleagues investigated the association between diagnostic phlebotomy and risk of HAA among 17,676 patients, in 57 medical centers, with AMI and no anemia at the time of admission, but who developed moderate to severe HAA, between 2000 and 2008. Total diagnostic blood loss for each patient was calculated by multiplying the standard volume for each tube type by the number and types of blood tubes drawn. The correlation between phlebotomy and risk of developing moderate to severe HAA was derived through hierarchical modified Poisson regression after adjusting for site and confounders.
The investigators found that 20 percent of the patients developed moderate to severe HAA. The mean phlebotomy volume was significantly higher in patients with HAA than without (173.8 mL versus 83.5 mL). Across the hospitals there was significant variability in mean diagnostic blood loss (moderate to severe HAA range from 119.1 to 246.0 mL; mild or no HAA range from 53.0 to 110.1 mL). Each 50 mL of blood drawn was associated with an 18 percent increased risk for moderate to severe anemia (relative risk, 1.18), which showed only a modest reduction after multivariable adjustment (relative risk, 1.15).
"Blood loss from phlebotomy is substantial in patients with AMI, varies across hospitals, and is independently associated with the development of HAA," the authors write.
Several of the study authors disclosed financial relationships with the pharmaceutical and health care industries.