Sex differences in the relations of positive and negative daily events and fatigue in adults with rheumatoid arthritis.

UNLABELLED: Fatigue is a common, disabling symptom for individuals with rheumatoid arthritis (RA). This study 1) examined sex differences in the relations between daily changes in positive and negative interpersonal events and same-day and next-day fatigue and 2) tested positive affect and negative affect as mediators of the associations between changes in interpersonal events and fatigue. Reports of fatigue, number of positive and negative interpersonal events, and positive and negative affect were assessed daily for 30 days via diaries in 228 men and women diagnosed with RA. Days of higher than average daily positive events were associated with both decreased same-day fatigue and increased next-day fatigue, but only among women. Sex differences in same-day relations between positive events and fatigue were mediated by increases in positive affect. For both sexes, days of higher than average daily negative events related to increased same-day and next-day fatigue, and the same-day relations between negative events and fatigue were mediated by increases in negative affect. A more nuanced understanding of similarities and differences between men and women in the associations between changes in interpersonal events and fatigue may inform future interventions for RA fatigue. PERSPECTIVE: This article presents an examination of sex differences in the links between changes in daily interpersonal events and fatigue in chronic pain patients. The findings can help clinicians target the psychosocial factors that potentially can ameliorate their patients' experience of fatigue.