Depression Moderates Physical Functioning Over Time in Survivors of Cancer.

BACKGROUND

Cancer survivors are at risk for declines in physical functioning (PF). The strongest predictor of PF is prior PF. Clinically significant depression predicts declines in PF; however, the extent to which depression symptoms moderate the association between self-reported and performance-based measures of PF over time is unknown.

OBJECTIVE/PURPOSE: To examine whether level of depression symptoms in cancer survivors moderates the association of repeated self- and performance-based measures of PF at 6 and 18 months after cancer diagnosis.

METHODS

Prospective, observational study with assessment at 6 (T1), 12 (T2), and 18 months after cancer diagnosis (T3).

SETTING AND PATIENTS

Community-dwelling US veterans with newly diagnosed head and neck, esophageal, gastric, or colorectal cancers.

MEASUREMENTS

Measures included demographics, cancer variables (type, stage, severity, and treatment), depression symptoms (Patient Health Questionnaire-9 [PHQ-9]), Short Physical Performance Battery (SPPB), and self-reported PF (Patient-Reported Outcomes Measurement Information System-29 [PROMIS-29]).

RESULTS

Using hierarchical regression models, after adjustment for covariates, depression symptoms at T2 moderated the relationship between performance-based PF, SPPB ( = -0.24, = .001) but not self-reported PF, PROMIS ( = -0.14, = .05). In moderation analyses, SPPB T1 was only related to SPPB T3 when the PHQ-9 score was less than 9.

LIMITATIONS

Majority White, male participants, did not measure chronicity of depression.

CONCLUSIONS

Depression symptoms moderate the relationship of performance-based PF from baseline to 18 months.