 Some pain after a major operation is expected, but some patients suffer more than others. More than 60% of surgical patients have moderate to severe postoperative pain, potentially predisposing them to persistent post-surgical pain. But who falls into which category? To better predict patients' pain and thereby provide better treatment, researchers at the University of Florida studied a large group of surgical patients to identify different pain trajectories. The team's work published in Anesthesiology revealed five distinct patterns determined in large part by patient-specific factors such as age, sex, and psychological features. The researchers monitored patients' pain reports for seven days and 360 patients recovering from a variety of different surgeries. Pain was evaluated using the Brief Pain Inventory, which asks for a patient's average, worst, and least pain in the last 24 hours to scale from 0 to 10. The team also collected clinical and socio-demographic information and data on the patient's preoperative mental and behavioral health. The researchers then used that information to perform group-based trajectory modeling and identify clusters of patients with similar pain trajectories. The best-fitting model pulled out five different trajectory groups, patients with low, moderate to low, moderate to high, and high pain over time, and one in which pain decreased rapidly. Nearly half of patients belonged to the moderate to high pain group, while only 6% of patients fell into the rapidly decreasing pain group. Generally, younger patients and women were more likely to belong to higher pain groups, and those in the highest pain group had higher anxiety and depression and greater pain behaviors before surgery. Patients in the moderate to high and high pain groups also took more opioids following surgery, and opioids taken before or during surgery were not associated with the pain trajectory group. Perhaps surprisingly, there was no link between the surgical procedure type and the trajectory groups. That's despite the patient cohort including multiple surgery types associated with severe and prolonged pain, such as spinal, thoracic, and orthopedic surgeries. Additionally, there was no connection between the pain trajectory group and whether patients received regional anesthesia. Finding suggests that patient sociodemographic and behavioral factors may be more important than procedural factors in determining how a person experiences post-surgical pain over time.