Relationships among pain and depressive and anxiety symptoms in
clinical trials of pregabalin in fibromyalgia.
Arnold LM, Leon T, Whalen E, Barrett J.
correspondence and M.D., 222 Piedmont Ave., Suite 8200, Cincinnati, OH
BACKGROUND: Fibromyalgia, as defined by the American College of
Rheumatology, is characterized by widespread pain lasting for at least
3 months, with pain in at least 11 out of 18 tender points when
palpated with digital pressure.
OBJECTIVE: The authors investigated the relationship between changes
in pain and symptoms of anxiety and depression, using data from
pregabalin clinical trials.
METHOD: Results from three double-blind, placebo-controlled trials of
pregabalin monotherapy in fibromyalgia (8-14 weeks) were pooled, and
baseline to end-point changes in pain and Hospital Anxiety and
Depression Scale (HADS) scores were analyzed. Path-analysis evaluated
the association between improvements in anxiety and depression and
RESULTS: Baseline HADS scores indicated moderate-to-severe anxiety in
38% of patients and moderate-to-severe depressive symptoms in 27%. The
improvement in pain was not related to baseline levels of anxiety or
depression. The correlation between changes in pain and depressive or
anxiety symptoms was low-to-moderate. Path-analysis showed that most
of the pain relief observed with pregabalin treatment was a direct
analgesic effect and was not explained by improvement in mood.
CONCLUSION: Response to treatment of pain in the pregabalin trials did
not depend on baseline levels of anxiety or depressive symptoms, and
pregabalin improved pain in fibromyalgia patients with or without
depressive or anxiety symptoms. Changes in the level of anxiety or
depression had a low-to-moderate impact on pain reduction. Pain
reduction with pregabalin treatment appeared to result mostly from a
direct treatment effect, rather than an indirect effect mediated
through improvement in anxiety or depressive symptoms.