Long versus short-term opioid therapy for fibromyalgia syndrome and risk of depression, sleep disorders and suicidal ideation: a population-based, propensity-weighted cohort study.

Objective: Fibromyalgia syndrome (FMS) is characterised by widespread pain and is associated with mood disorders such as depression as well as poor sleep quality. These in turn have been linked to increased risk of suicidal ideation. Clinical guidelines generally do not recommended opioids in FMS, but they are routinely prescribed to a considerable proportion of FMS patients. We assessed the association of long-term opioid prescription for FMS with risk of depression, sleep disorders and suicidal ideation, when compared with short-term opioid use.

Methods: Retrospective cohort study combing several population-wide databases covering a population of five million inhabitants, including all adults who received an initial opioid prescription from 2014 to 2018 specifically prescribed for FMS. We examined the occurrence of depression, sleep disorders or suicidal ideation outcomes in patients with an initial long-term opioid prescription (>90 days) versus those who received a short-term treatment (<29 days). We employed multivariable Cox regression modelling and inverse probability of treatment weighting based on propensity scores and we performed several sensitivity analyses.

Results: 10 334 patients initiated short-term (8309, 80.40%) or long-term (2025, 19.60%) opioids for FMS. In main adjusted analyses, long-term opioid use was associated with an increased risk for depression (HR: 1.58, 95% CI 1.29 to 1.95) and sleep disorder (HR: 1.30, 95% CI 1.09 to 1.55) but not with suicidal ideation (HR: 1.59, 95% CI 0.96 to 2.62). In models assessing outcomes since day 90, an increased risk for suicidal ideation was observed (HR: 1.76, 95% CI 1.05 to 2.98).

Conclusion: These findings suggest that continued opioid use for 90 days or more may aggravate depression and sleep problems in patients with FMS when compared with patterns of short-term treatment.