Background: Multiple professional societies recommend red blood cell transfusions for hospitalized patients based on the presence of symptoms of anemia, like fatigue. These recommendations endorse the idea that the severity of anemia symptoms are due to a patient’s nadir or reduced hemoglobin (Hb) concentration, and that correcting the Hb concentration with a transfusion will improve a patient’s symptoms. However, these recommendations are supported by data collected in post-op surgical patients, limiting the generalizability to hospitalized medical patients. Further, while it is assumed that fatigue is associated with Hb concentration, this association has only been tested in certain ambulatory patient populations, and not in hospitalized patients who may have fatigue from their acute illness and their underlying anemia. Therefore, to determine if patient fatigue provides a justification for a transfusion, it is first necessary to establish if any measure of anemia is associated with fatigue in hospitalized patients.
Our aim was to explore multiple Hb measures in hospitalized general medicine patients with anemia, and to test if there is an appropriate Hb measure that is associated with patients’ anemia-related fatigue.
Methods: From April 2014 through June 2015, hospitalized general medicine patients at a single urban academic medical center with age≥50 years old and Hb<9g/dL were approached for an interview while hospitalized. Patients were asked the Functional Assessment of Chronic Illness Therapy (FACIT) Fatigue Subscale to measure fatigue. FACIT Fatigue scores range from 0-52, with lower scores reflecting greater amounts of fatigue. Patients’ Hb concentration while hospitalized was determined using hospital administrative data. Associations between fatigue and Hb were tested using descriptive statistics, χ2 tests, and linear regression.
Results: During the study period 821 participants completed the inpatient interview. The mean age of participants was 67 years old, 55% (455/821) were female, and 57% (471/821) were African American. The mean FACIT Fatigue score was 26 (median 27). The mean Hb of participants was 8.5 (median 8.5). Correlation between fatigue and a patient’s mean (r=0.0), nadir (r=0.1), and max (r=-0.1) Hb during their hospitalization was not strong. Patients whose nadir Hb was between 7-8g/dL were more likely to have higher amounts of fatigue (FACIT <27) (34% vs 24%, p<0.01), than those whose nadir Hb was >8g/dL (FACIT ≥27) (39% vs 29%, p<0.01). In linear regression models the mean and max Hb during a hospitalization were not significant predictors of fatigue, but the nadir Hb was (β=0.86, p=0.04) when controlling for age, sex and comorbidities.
Conclusions: Patients’ nadir Hb during their hospitalization is predictive of anemia-related fatigue. Hospitalists and inpatient providers can use nadir Hb to determine the amount of fatigue a hospitalized patient is experiencing, and as a reflection of the fatigue they may continue experience at that Hb concentration.