Interference with activities due to pain and fatigue: accuracy of ratings across different reporting periods

Abstract

Purpose: This study examined the impact of different reporting period lengths on the accuracy of items measuring interference due to pain and fatigue with work, walking, and relations with others.

Methods: Six items from well-established instruments (Brief Pain Inventory, Brief Fatigue Inventory, SF-36) were investigated in a prospective study of 117 patients with chronic rheumatological illness. Daily ratings were compared with recall ratings of 1, 3, 7, and 28-day reporting periods.

Results: The level of recall ratings (RRs) for reporting periods of 3 days or more were significantly higher than the level of aggregated end-of-day (EOD) ratings. Correspondence between aggregated EOD and RRs was good (r ≥ .80) regardless of the length of the reporting period. Ratings of interference for a single day were highly correlated with aggregated EOD for up to 14 days prior to the single rating (r ≥ .76).

Conclusions: Recall ratings with reporting periods of up to a month yield good correspondence with aggregated daily ratings, although the absolute level of the rating will be inflated for recall periods of 3 days or longer.

Figure 1

Mean end-of-day ratings and recall ratings of pain interference (left panel) and fatigue interference (right panel) with (a) walking, (b) work, and (c) social activities. Error bars represent standard errors.

Figure 2

Correlations of recall ratings with the average of end-of-day ratings for pain interference and fatigue interference items.