A study published in CMAJ (Canadian Medical Association Journal) says that high erythropoietin levels in people over age 85 indicate a higher risk of death.
Erythropoietin is a hormone created in the kidneys to stimulate production of red blood cells. Production is triggered by impaired oxygen delivery to the kidney because of anemia or low blood oxygen levels. In patients with chronic heart failure, high erythropoietin levels predict higher mortality.
The researchers looked at data from the Leiden 85-plus Study which involved 428 people aged 85 years or older in Leiden, the Netherlands.
They found that "high erythropoietin levels were associated with increased mortality, independent of creatinine clearance, hemoglobin level, the presence of comorbidity, smoking and circulating markers of inflammation," writes Wendy den Elzen, Leiden University Medical Centre, Leiden, the Netherlands, with coauthors.
"We showed that elevated erythropoietin has important prognostic value for mortality in the general population of older individuals," write the authors. "However, we do not know whether high erythropoietin, apart from being a risk marker of increased mortality in old age, is also a causal risk factor of increased mortality."
They call for further studies to look into the underlying biological mechanism and to understand the clinical implications of a high erythropoietin level in older people.