Borderline anemia increases risk of death in coronary disease
Earlier posts have offered evidence for the need to take even slightly low levels of hemoglobin very seriously. Now a research article just published in PLoS Medicine (Public Library of Science) reports that borderline anemia makes coronary artery disease significantly more lethal. The authors note:
"Coronary artery disease is the main cause of death in high-income countries and the second most common cause of death in middle- and low-income countries...Recent studies have suggested that low hemoglobin may be associated with mortality in patients with coronary artery disease. Therefore, using blood hemoglobin level as a prognostic biomarker for patients with stable coronary artery disease may be of potential benefit especially as measurement of hemoglobin is almost universal in such patients and there are available interventions that effectively increase hemoglobin concentration."
They examined the data for 20,131 with stable angina and another 14,171 who had survived a first heart attack for an average of 3.2 years, correlating outcomes with hemoglobin values. Their findings are very important for clinicians and patients, who should inquire about their hemoglobin values, to bear in mind:
"For men with MI, the threshold value was 13.5 g/dl; the 29.5% of patients with haemoglobin below this threshold had an associated hazard ratio for mortality of 2.00 compared to those with haemoglobin values in the lowest risk range. Women tended to have lower threshold haemoglobin values (e.g, for MI 12.8 g/dl) but the shape and strength of association did not differ between the genders, nor between patients with angina and MI."
In other words, hemoglobin below 13.5 g/dl in men and slightly lower in women doubled the risk of death. The authors conclude:
"There is an association between low haemoglobin concentration and increased mortality. A large proportion of patients with coronary disease have haemoglobin concentrations below the thresholds of risk defined here."