Original Research

Association Between Anemia and Fatigue in Hospitalized Patients: Does the Measure of Anemia Matter?


BACKGROUND: Restrictive blood transfusion practices in hospitalized patients with anemia have reduced the use of transfusion. Consequently, hospitalized patients are more likely to have lower hemoglobin (Hb) concentrations. Lower Hb is associated with increased fatigue in ambulatory patients. However, it is not known whether anemia is associated with fatigue in hospitalized patients. It is also unclear how to best measure anemia in hospitalized patients because Hb levels generally vary over a hospital stay.

OBJECTIVE: To assess multiple Hb-based measures of anemia in hospitalized patients and test whether these are associated with fatigue.

DESIGN: Prospective observational study.

SETTING: Urban, academic medical center.

PATIENTS: Hospitalized general medicine patients, age ≥50 years, with any Hb < 9 g/dL.

INTERVENTION: Patients’ anemia-related fatigue was measured during hospitalization.

MEASUREMENTS: Measures of anemia were created for each patient based on the Hb values from their hospitalization (mean, median, minimum, maximum, admission, and discharge). Fatigue was measured using the Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue subscale.

RESULTS: Seven hundred eighty-four patients participated. Minimum Hb was strongly associated with fatigue. Patients with a minimum Hb of < 8 g/dL had higher fatigue levels (mean FACIT [standard deviation] Hb < 7 g/dL: 25 [13], 7 g/dL ≤ Hb <8 g/dL: 25 [14] Hb ≥8 g/dL: 29 [14], P ≤ 0.001) and were more likely to report high levels of fatigue (FACIT-Fatigue < 27) (56% vs 41%; P = 0.002). Mean Hb had a less robust association with fatigue than minimum Hb, and no other measure of Hb was associated with patients’ fatigue levels.

CONCLUSION: Minimum Hb is associated with fatigue while hospitalized and may help identify patients for interventions to address anemia-related fatigue.

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