Classification of acute pain trajectory after breast cancer surgery identifies patients at risk for persistent pain: a prospective observational study

Akiko Okamoto,1,2 Masaki Yamasaki,3 Isao Yokota,4 Maiko Mori,3 Megumi Matsuda,3 Yosuke Yamaguchi,3 Shunsuke Yamakita,3 Hiroshi Ueno,2 Teiji Sawa,3 Tetsuya Taguchi,1 Toyoshi Hosokawa,2 Fumimasa Amaya3 1Department of Endocrinological and Breast Surgery, 2Department of Pain Management and Palliative Care Medicine, 3Department of Anesthesiology, 4Department of Biostatistics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan Purpose: Predictive value and accuracy of the acute pain trajectory were compared with those of pain intensity at 1 day after the surgery for pain prevalence at 6 months after the surgery.Materials and methods: Female patients scheduled for breast cancer surgery were eligible for this study. Patients were questioned about pain intensity daily during the 7 days after surgery. Presence of pain, its location, and intensity as well as the Japanese version of the quality of the recovery-40 (QOR-40) were determined in an interview prior to and at 6 months after the surgery. Acute pain trajectory was determined by a group-based trajectory modeling analysis that was based on the pain intensity at 1–7 days after surgery. Predictive value of the acute pain trajectory for the presence of pain at 6 months after the surgery was assessed by a logistic regression model. The predictive value was compared with pain intensity at 1 day after the surgery.Results: A total of 123 participants completed the 6-month follow-up. The three-cluster model (mild, moderate, and severe pain) was considered to be the most statistically appropriate model for the acute pain trajectory. After 6 months, 51.2% and 8.9% of participants reported pain and severe pain, respectively. Presence of pain at 6 months after the surgery was associated with poor recovery. The severe pain cluster was significantly associated with the presence of pain at 6 months after the surgery (adjusted odds ratio, 9.40; P<0.001 vs mild pain cluster).Conclusion: Classification of patients according to the acute pain trajectory, when compared with the classification according to pain intensity at 1 day after the surgery, made it possible to predict with better precision those patients who will develop persistent postsurgical pain. Keywords: group-based trajectory analysis, acute postsurgical pain, chronic postsurgical pain, quality of recovery, breast cancer surger