For patients with chronic low-back pain, the benefits of cognitive-behavioral therapy and mindfulness-based stress reduction that were reported at 6 months and 1 year largely disappeared by 2-year follow-up, according to a Research Letter to the Editor published Feb 14 in JAMA.

In a clinical trial involving 342 affected patients aged 20-70 years, participants were randomly assigned to receive CBT (113 patients), mindfulness-based stress reduction (MBSR, 116 patients), or usual care (113 patients) and followed up at 26 weeks. The two psychological interventions were delivered in 2-hour group sessions every week for 8 weeks. As previously reported, both CBT and MBSR reduced functional limitations and decreased the “bothersomeness” of the pain, as measured by scores on the modified Roland Disability Questionnaire, compared with usual care, said Daniel C. Cherkin, PhD of the Group Health Research Institute, Seattle, and his associates.

They now report their results at extended, 2-year follow-up (1.4-2.8 years after randomization) for 75% of the CBT group, 78% of the MBSR group, and 89% of the usual-care group. The differences between the three study groups in functional limitations and bothersomeness of the pain were no longer significant, even though the proportion of participants who showed 30% or more improvement from baseline on the RDQ remained numerically higher for CBT (62%) and MBSR (55%) than for usual care (42%). The only significant difference among the study groups was a “modest” benefit of CBT over usual care in functional limitation, the investigators said (JAMA 2017;317:642-4).

This study was limited in that few participants in the two intervention groups attended all eight of their weekly CBT or MBSR sessions, and only 60% attended six sessions.

Further study is needed to determine whether strategies to increase adherence to these therapies, or “booster sessions” added months after the eight scheduled sessions, would help maintain the short-term benefits, Dr. Cherkin and his associates said.