What disorder is most consistent with a hemoglobin concentration of 18.5 g/dL in a 57-year-old man?

A hemoglobin concentration of 18.5 g/dL in a 57-year-old man suggests a state of erythrocytosis, which can occur due to various underlying conditions. Chronic obstructive pulmonary disease (COPD) is a well-known cause of secondary erythrocytosis. In COPD, long-term hypoxia results from impaired lung function and reduced oxygenation of the blood. The body compensates for low oxygen levels by producing more red blood cells, which leads to an increase in hemoglobin concentration.

In the context of this patient's elevated hemoglobin level, COPD is a plausible explanation because it directly relates to oxygen deficiency and the resultant physiological response of hyperproduction of erythrocytes. This is particularly relevant in older adults with a smoking history or exposure to pollutants that could contribute to chronic lung disease.

Other conditions listed may cause changes in blood components but are less directly linked to the specific level of elevated hemoglobin concentration. For example, conditions like agnogenic myeloid metaplasia (now known as primary myelofibrosis) and hereditary hemochromatosis can also lead to increased hemoglobin but are typically associated with other hematologic abnormalities or clinical features that may not solely present as elevated hem