After an Episode of Acute Low Back Pain, Recurrence Is Unpredictable and Not as Common as Previously Thought

In Brief Study Design. Inception cohort study. Objective. To provide the first reliable estimate of the 1-year incidence of recurrence in subjects recently recovered from acute nonspecific low back pain (LBP) and to determine factors predictive of recurrence in 1 year. Summary of Background Data. Previous studies provide potentially flawed estimates of recurrence of LBP because they do not restrict the cohort to those who have recovered and are therefore eligible for a recurrence. Methods. We identified 1334 consecutive patients who presented to primary care with acute LBP; of these 353 subjects recovered before 6 weeks and entered the current study. The primary outcome measure was recurrence of LBP in the next year. Specifically, an episode of recurrence was defined in 2 ways: recall of recurrence at the 12-month follow-up and report of pain at the 3- or 12-month follow-up. Risk factors for recurrence were assessed at baseline. Pain intensity was assessed at 6 weeks, 3 months, and 12 months and recurrence at 12 months. Factors that could plausibly affect recurrence were chosen a priori and evaluated using a multivariable regression analysis. Results. Recurrence of LBP was found to be much less common than previous estimates suggest, ranging from 24% (95% CI = 20%–28%) using “12-month recall” definition of recurrence, to 33% (95% CI = 28%–38%) using “pain at follow-up” definition of recurrence. However, only 1 factor, previous episode(s) of LBP, was consistently predictive of recurrence within the next 12 months (odds ratio = 1.8–2.0, P = 0.00–0.05). Conclusion. This study challenges the assumption that the majority of subjects will have a recurrence of LBP in a 1-year period. After the resolution of an episode of acute LBP, about 25% of subjects will have a recurrence in the next year. It is difficult to predict who will have a recurrence within the next year. This study investigated the incidence and the predictive factors of recurrence in primary care patients recently recovered from acute low back pain. In the year after the initial episode, recurrence of low back pain was less common (24%–33%) than previous estimates suggest, although difficult to predict. Only 1 factor, previous episode(s) of low back pain, was consistently predictive of recurrence.