CONTEXT: Fatigue is one of the most prevalent symptoms among haemodialysis (HD) patients. In order to design effective treatments it is crucial to understand the diurnal pattern of fatigue in this population.
OBJECTIVES: To assess diurnal changes in fatigue in patients undergoing haemodialysis and their relation with depressive symptoms. To explore whether fatigue may become a classically conditioned response to the hospital environment.
METHODS: A prospective, observational study was conducted in fifty-one HD patients. Subjects repeatedly rated their current fatigue on three different days during one week of haemodialysis treatment to capture changes in momentary fatigue. First, on a HD treatment day, fatigue was measured one hour before and immediately prior to dialysis, as well as immediately after dialysis and again at 22:00 p.m. Second, on the post-dialysis day and on the seventh weekday (when patients had not received treatment on the previous day), fatigue was measured at the same moments in time as the two measurements before dialysis on the treatment day. Beck Depression Inventory-II and Fatigue Severity Scale were administered to evaluate depressive mood and fatigue severity in daily life.
RESULTS: Fatigue increased as a result of haemodialysis treatment over the entire sample. However, diurnal fatigue patterns differed significantly between individuals high and low in depressive symptoms, with the former being fatigued more constantly throughout the day, and the latter experiencing increases in fatigue due to treatment. Pre-treatment fatigue experienced in the hospital environment followed a pattern consistent with the development of a classically conditioned response.
CONCLUSIONS: Diurnal fatigue patterns during haemodialysis treatment are associated with depressive symptoms, and classical conditioning may play a role in the experience of pre-treatment fatigue.
- classical conditioning
- momentary assessment