Acute Pain Characteristics in Patients with and without Chronic Pain following Lower Extremity Injury.

The final sample was 129 patients, while the power analysis stated 381 patients were required, and the authors say the study might not have been powered enough to detect differences based on pain trajectories. Only 129 of 516 eligible patients were enrolled. Half of eligible patients did not answer the call, and 16% responded it was a wrong number, so the sample may not represent all eligible trauma patients. The study used retrospective medical records and telephone recall, and the authors say not all pain scores obtained during assessment may have been documented. Pain scores were recorded with the vital signs and during routine care, and scores outside the 0 to 10 NRS had to be recoded or treated as missing. Some scores were illegible. The three-month cutoff for chronic pain may have included patients whose injuries had not healed and who were still experiencing acute pain. The sample was limited to English-speaking patients with lower extremity fractures and a telephone number, and the study could not collect data on untreated anxiety, depression, or years of education. Pain trajectory estimates depended on the number of documented pain scores, and one patient had only four pain scores recorded.

The article is listed as Research Support, N.I.H., Extramural. The authors declared no conflicts of interest.

Do not conclude that lowering inpatient pain scores prevents chronic pain. This was an observational study of associations, and it did not test pain treatment or its effect on chronic pain outcomes.