Pain One Week After an Emergency Department Visit for Acute Low Back Pain Is Associated With Poor Three‐month Outcomes

• Published in: Academic emergency medicine Vol. 25; no. 10; pp. 1138 - 1145
• Main Authors: Friedman, Benjamin W., Conway, John, Campbell, Caron, Bijur, Polly E., John Gallagher, E., Bird, Steven B.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.10.2018
• Subjects: Back pain; Chronic pain; Clinical outcomes; Data analysis; Disability; Emergency medical care; Medical prognosis
• ISSN: 1069-6563; 1553-2712
• DOI: 10.1111/acem.13453

Background Low back pain (LBP) is responsible for more than 2.5 million visits to U.S. emergency departments (EDs) annually. Nearly 30% of patients who present to an ED with acute LBP report functional impairment or pain 3 months later. These patients are at risk of chronic LBP, a highly debilitating condition. In this study, we assessed whether three variables assessable shortly after symptom onset could independently predict poor 3‐month outcomes among LBP patients who present to an ED. Methods This was a planned analysis of data from two randomized comparative effectiveness studies of patients with acute, nontraumatic, nonradicular LBP. Patients were enrolled during an ED visit, contacted by telephone 1 week after the ED visit, and then followed up by telephone 3 months later. The coprimary 3‐month outcomes were LBP‐related functional impairment and persistent moderate or severe LBP. Two of the three hypothesized predictor variables were assessed during the index visit: 1) the STarT Back Screening Tool score, a nine‐item, multidimensional tool validated and widely used in the outpatient setting, and 2) the patient's own anticipated duration of LBP. The third hypothesized predictor was presence of pain assessed by phone 1 week after the ED visit. We then determined whether these three predictor variables were independently associated with poor outcomes at 3 months, after controlling for medication received, age, and sex. Results A total of 354 patients were enrolled. Of these, 309 (87%) provided 3‐month impairment data and 311 (88%) provided 3‐month pain data. At 3 months, 122 of 309 (39%) patients reported functional impairment and 51 of 311(16%) patients reported moderate or severe LBP. Among the three hypothesized predictor variables, 58 of 352 (16%) patients with available data reported a moderate or high STarT Back Screening Tool score, 35 of 321 (11%) patients with available data reported anticipated duration of LBP > 1 week, and 235 of 346 (68%) patients reported pain at 1‐week telephone follow‐up. After age, sex, and medication received were controlled for in a multivariable logistic regression model, only pain at 1 week was independently associated with 3‐month impairment (odds ratio [OR] = 2.42, 95% CI = 1.39–4.22) and 3‐month moderate or severe pain (OR = 3.83, 95% CI = 1.53–9.58). Conclusions More than one‐third of patients reported functional impairment 3 months after an ED visit for acute, nontraumatic, nonradicular LBP. Moderate or severe LBP was less common, reported in about half as many patients (16%). Of the three hypothesized predictor variables, only persistent pain at 1 week was independently associated with poor outcomes at 3 months. Despite its important role in the outpatient setting, the STarT Back Tool was not associated with poor outcomes in this ED cohort.