Unintentional weight loss, body composition, and all-cause mortality among United States adults with cancer.

Abstract

e22527 Background: While unintentional weight loss (UWL) is a common presenting symptom of malignancy, weight changes also occur regularly in patients with diagnosed cancer.UWL is often characterized by considerable muscle and fat loss and can lead to cachexia, which may increase risk of mortality. This nationally representative study aims to assess the association between UWL and mortality among adults with history of cancer and characterize differences in body composition. Methods: This was a retrospective cohort study of the National Health and Nutrition Examination Survey 1999-2018 linked to the 2019 National Death Index. We identified adults with self-reported history of cancer, excluding non-melanoma skin cancer. Weight change was determined as the difference between current weight and self-reported weight 1 year prior to interview. We categorized weight change into: UWL (unintentionally losing > 5% of weight), intention weight loss (IWL) (intentional loss > 5% weight), no weight change (NWC) (≤5% weight change), weight gain (WG) ( > 5% weight gain). We estimated risk of all-cause mortality using gender-stratified multivariable Cox regression, adjusting for demographics (age, race, income, education, insurance status), sociobehavioral factors (smoking, alcohol, nutrition, physical activity, self-reported health), comorbidities, and albumin. We additionally identified participants with cancer who had whole-body dual x-ray absorptiometry scans (2011-2018) and assessed body composition measurements including total lean mass, lean-to-fat ratio, subcutaneous fat mass, and visceral fat mass by weight change category using multivariable linear regression. Results: Among 3,153 participants (mean age 62 years, 55% women, 82% non-Hispanic White), the top four primary cancers were breast (21%), prostate (14%), melanoma (11%), and cervical (11%). Approximately 9% of men and 11% of women experienced UWL. Adults with UWL were more likely to have lower socioeconomic status, more functional limitations, and higher comorbidity burden. Across a median 7 years (IQR, 3-11y) follow-up, 22% of females and 34% of men died. Both men and women experiencing UWL had more than 2 times the risk of all-cause mortality compared to NWC (adjusted HR [95% CI]; men: 2.02 [1.47, 2.78]), women: 2.43 [1.78, 3.34]). Participants with UWL had less subcutaneous fat mass (-113g, 95% CI [-242, 16]) and visceral fat mass (-65g, 95% CI [-146, 16]) compared to NWC, though not statistically significance. Conclusions: UWL in patients with history of cancer is independently associated with more than 2 times the risk of all-cause mortality in both men and women. UWL was associated with proportional loss of both subcutaneous and visceral fat mass. Further longitudinal studies examining UWL’s impact on body composition changes and downstream outcomes by cancer type and stage are needed.