Zwart JA, Dyb G, Hagen K, Svebak S, Holmen J
Department of Clinical Neuroscience (Drs. Zwart and Hagen),
Section of Neurology, Department of Psychiatry and Behavioural Medicine (Drs. Dyb and Svebak),
and HUNT Research Centre (Dr. Holmen), Faculty of Medicine, Norwegian University of Science and Technology, Trondheim.
OBJECTIVE: To examine the relation between analgesic use at baseline and the subsequent risk of chronic pain (>/==” BORDER=”0″>15 days/month) and the risk of analgesic overuse.
METHODS: In total, 32, 067 adults reported the use of analgesics in 1984 to 1986 and at follow-up 11 years later (1995 to 1997). The risk ratios (RR) of chronic pain and RR of analgesic overuse in the different diagnostic groups (i.e., migraine, nonmigrainous headache, neck pain, and low-back pain) were estimated in relation to analgesic consumption at baseline.
RESULTS: Individuals who reported use of analgesics daily or weekly at baseline showed significant increased risk for having chronic pain at follow-up. The risk was most evident for chronic migraine (RR = 13.3, 95% CI: 9.3 to 19.1), intermediate for chronic nonmigrainous headaches (RR = 6.2, 95% CI: 5.0 to 7.7), and lowest for chronic neck (RR = 2.4, 95% CI: 2.0 to 2.8) or chronic low-back (RR = 2.3, 95% CI: 2.0 to 2.8) pain. Among subjects with chronic pain associated with analgesic overuse, the RR was 37.6 (95% CI: 21.3 to 66.4) for chronic migraine, 14.4 (95% CI: 10.4 to 19.9) for chronic nonmigrainous headaches, 7.1 for chronic neck pain (95% CI: 5.5 to 9.2), and 6.4 for chronic low-back pain (95% CI: 4.9 to 8.4). The RR for chronic headache (migraine and nonmigrainous headache combined) associated with analgesic overuse was 19.6 (95% CI: 14.8 to 25.9) compared with 3.1 (95% CI: 2.4 to 4.2) for those without overuse.
CONCLUSION: Overuse of analgesics strongly predicts chronic pain and chronic pain associated with analgesic overuse 11 years later, especially among those with chronic migraine.