Background: The goal of this study was to develop and validate the overall benefit of analgesic score (OBAS), which assesses pain intensity and the opioid-related adverse effects.
Methods: The score was developed and validated in four trials (n=1470 patients). Data from randomized trial I were used to develop the OBAS (factor analysis). Data from randomized trial II were used to compare the resolution of rofecoxib's analgesic effects between OBAS and pain scores. Randomized trial III (spine surgery) was conducted to evaluate prospectively the reliability of the OBAS and to compare its resolution of analgesic treatment with the opioid-related symptom distress scale (OR-SDS) and the modified brief pain inventory short form (m-BPI-sf). Trial IV was conducted to evaluate in patients with a moderate-to-high level of postoperative pain (after major abdominal surgery) the relation of OBAS and pain scores for patients' satisfaction with analgesic therapy.
Results: The seven-item OBAS yielded a higher resolution of analgesic treatment effects than pain scores, the OR-SDS and m-BPI-sf. The OBAS has a fair inter-rater reliability (concordance correlation of 0.71 c) and is more sensitive (P=0.03) in indicating the delivery of opioid boluses than the dedicated OR-SDS. The OBAS, but not pain scores at rest or pain scores during movement, explained significant variance in patients' satisfaction with postoperative pain therapy.
Conclusions: The OBAS is a simple, multi-dimensional quality assessment instrument to measure patients' benefit from postoperative pain therapy. Opioid symptom distress, pain relief, and patients' satisfaction are combined in a reliable and valid tool.