Analgesics are commonly used by patients with low back pain despite their limited effects on pain and function and their potential risk of side effects. However, little is known about how psychological factors and interventions aimed at increasing self-efficacy influence analgesic use.
The aim of the study was to investigate whether analgesic use changed after participation in an education and exercise program; to assess the extent to which baseline analgesic use and self-efficacy influenced analgesic use after the program; and to examine whether improvements in self-efficacy from before to after the intervention modified the association between baseline and follow-up analgesic use.
The study was based on data from GLA:D® Back (2018–2023). Analgesic use and self-efficacy were self-reported. The outcome was analgesic use at the 3-month follow-up. Logistic regression was used to investigate associations and effect modification.
A total of 4,721 GLA:D® Back participants were included in the study. Among those who used analgesics at baseline, 66% reported continued use at the 3-month follow-up, while 34% had stopped using them.
Baseline analgesic use was associated with higher odds of analgesic use at the 3-month follow-up, whereas higher baseline self-efficacy was associated with lower odds.
Improved self-efficacy during the program did not modify the association between baseline and follow-up analgesic use on the multiplicative (log-odds) scale. However, it reduced the absolute risk of analgesic use at follow-up from 15% to 6% among participants who did not use analgesics at baseline and from 76% to 54% among those who did use analgesics at baseline (i.e., a negative additive interaction).
Patients with low back pain who used analgesics before starting treatment were more likely to be using analgesics three months later, whereas those with higher self-efficacy were less likely to do so. Improvements in self-efficacy from before to after participation in GLA:D® Back reduced the absolute risk of post-program analgesic use to a greater extent among participants who used analgesics at baseline than among those who did not.
The article is based on a Master’s thesis from the Department of Clinical Biomechanics, University of Southern Denmark (SDU).
Maya Tabul, Alice Kongsted, Jan Hartvigsen, Melker Johansson. The role of preexisting analgesic use and self-efficacy for continued use of analgesics among patients with persistent low back pain. Chiropractic & Manual Therapies 2025.
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