The relationship between psychologic distress and cancer-related fatigue

The authors examined the relationship between changes in depression and anxiety levels with changes in fatigue levels among anemic patients with lung cancer who participated in a randomized, double-blind, placebo-controlled clinical trial of darbepoetin alfa for the treatment of anemia.

Patients completed the Brief Symptom Inventory (BSI) Depression and Anxiety subscales and the Functional Assessment of Cancer Therapy (FACT) Fatigue subscale during the trial. Pearson correlation coefficients were used to compare changes in the BSI scores with changes in the FACT Fatigue scores. Multiple regression models were used to explore sociodemographic and clinical explanatory variables.

At baseline, 25% and 35% of 250 patients reported high levels (normed BSI scores >or= 65) of anxiety and depression, respectively. Correlations of changes in normed BSI Anxiety and Depression subscale scores with changes in FACT Fatigue scores had coefficients of -0.45 (P < 0.001) and -0.44 (P < 0.001), respectively. In the multiple regression models, change in the FACT Fatigue score was the only significant explanatory variable (P < 0.001). For every unit improvement in FACT Fatigue score, there was a corresponding improvement of 0.7 points and 0.8 points in anxiety and depression levels, respectively.

Improvements in fatigue were associated significantly with reductions in anxiety and depression. For patients with anemia, fatigue can be improved or reversed with darbepoetin alfa therapy. Thus, less fatigued patients also may benefit from reduced levels of anxiety and depression.