The correlation between fatigue, physical function, the systemic inflammatory response, and psychological distress in patients with advanced lung cancer.

Functional disability is reported frequently in fatigued cancer patients, but little is known about the correlation between fatigue and objective physical function. In addition, from previous work, the systemic inflammatory response and psychological distress appear to be related to fatigue. Thirty-eight patients with metastatic or locally advanced lung carcinoma and 15 age-matched and gender-matched, healthy controls completed the Functional Assessment of Chronic Illness Therapy-Fatigue scale, a visual analogue weakness score, and the Hospital Anxiety and Depression (HAD) scale. Hemoglobin concentrations, C-reactive protein (CRP) concentrations, creatine kinase concentrations, white blood cell count, body composition, Karnofsky performance status (KPS), grip strength, and chair-rise time also were measured in both groups. The cancer patients were then grouped into tertiles on the basis of fatigue scores. The cancer patients had greater fatigue compared with the control group (P < 0.001). They also weighed less, had lower hemoglobin and creatine kinase levels and higher CRP levels, and had lower KPS, poorer grip strength, longer chair-rise times, and increased HAD scale scores (all P < 0.01). KPS and chair-rise time were correlated strongly (r(2) = 0.565; P < 0.001). With increasing fatigue, KPS was lower, and chair-rise time and HAD scale scores were greater (P < 0.01). On multiple regression analysis, only KPS, weakness, and HAD scale scores were correlated independently with fatigue (r(2) = 0.570; P < 0.001). Objective physical function (as measured by chair-rise time) in patients with advanced lung cancer was poorer with increasing fatigue. Results of the current study suggest that fatigue is not a result primarily of weight loss or anemia but is related to KPS and psychological distress.