Comparison of daily and weekly retrospectively reported pain intensity in patients with localized and generalized musculoskeletal pain.

The purpose of the study was to compare daily and weekly recalled pain intensity over time and their correspondence with real-time pain intensity in patients with localized (LP) and generalized (GP) musculoskeletal pain. Daily recalled pain, averaged over seven consecutive days, and weekly recalled pain at day 8 were recorded on 100 mm visual analogue scales monthly over 4 months for 40 LP and 50 GP patients. Multiple real-time pain ratings on numerical rating scales (0-10) were averaged over the week for 23 LP and 33 GP patients in Month 4. Reliability was assessed using the intraclass correlation coefficients (ICC) and the standard deviations of the repeated measurements. Daily pain ratings were lower than weekly ratings across the 4-month period. Reliability was lower for weekly than for daily recalled pain in the GP group, and lower than in the LP group. These results were independent of the magnitude of pain intensity. No difference was found between daily recalled and real-time ratings. The ICC was higher between daily and real-time ratings than between weekly and real-time ratings in Month 4. Weekly ratings were higher than real-time ratings in the GP group, and the overestimation increased with increasing pain intensity. The results of the present study indicated that reliability was improved by using ratings of daily recalled pain averaged over a week rather than single ratings of weekly recalled pain in subjects with localized or generalized pain. Weekly recalled pain was overestimated in subjects exhibiting generalized pain and high pain intensity.