Presentation: Electronic Diaries Have Superior Discrimination Compared to Paper-Based Pain Assessment in Individuals with Fibromyalgia (2007)

1537 Electronic Diaries Have Superior Discrimination Compared to Paper-Based Pain Assessment in Individuals with Fibromyalgia

Purpose: The pain intensity associated with Fibromyalgia (FM) can fluctuate widely during the course of a single day. As such, traditional clinic-based assessment of pain with paper-based Visual Analogue Scale (VAS) measures may not sufficiently capture the experience of pain in FM. More frequent assessments and/or real-time assessments in the home environment are possible with electronic pain diaries. This study sought to compare the performance of electronic diary to paper-based assessments of pain intensity over a 6-month period in the context of a large RCT of milnacipran, a potential treatment for fibromyalgia.
Methods: A total of 888 FM patients over 50 sites were randomized to placebo (n=223), 100 mg (n=224), or 200 mg (n=441) of milnacipran. Pain ratings were collected monthly during clinic visits using traditional measures (i.e., VAS of average pain intensity over the last week, VAS of average pain intensity over the previous 24 hours) and through the use of daily monitoring with an electronic diary (e-diary). Pain intensity ratings were captured by participants using e-diaries at semi-random times 3-5 times daily, a morning recall of the average pain intensity for the previous 24 hours, as well as average pain intensity over the last week (collected once per week).
Results: Correlations between each of the 5 pain intensity measures ranged between r=0.56-0.92 at baseline, to a range of r=0.8-0.98 at the 6-month endpoint. Effect sizes (Cohen’s d) for change in pain at 6 months relative to baseline were calculated comparing each treatment arm to placebo. All 3 e-diary measures displayed larger effect sizes than did the traditional paper measures by approximately 50%. There also was a consistent finding that the pain intensity scores reflected the recall interval; i.e., the longer the recall interval, the greater the reported pain intensity score at baseline and follow-up.
Conclusions: Despite the pain intensity measures being highly correlated, e-diary methods consistently provided greater power to detect differences in pain between groups as compared to traditional paper methods. It is clear that e-diaries provide a greater array of pain data than that available through clinic-based assessments. In addition, electronic collection assesses pain real-time or near real-time data minimizing recall bias. This finding of improved discrimination with e-diaries indicates a clinical advantage to assessing pain on a more frequent basis in the patients’ natural environment.

  D.A. Williams, Cypress Bioscience, Inc., 5; R. Gendreau, Cypress Bioscience, Inc., 3; D.J. Clauw, Cypress Bioscience, Inc., 1; Cypress Bioscience, Inc., 5; Pfizer Inc, 5; Wyeth Pharmaceuticals, 5; Eli Lilly and Company, 5.