Although statins have been linked to increased risk of myopathy, an article in the May 14 issue of Neurology suggests that peripheral neuropathy may also be a delayed adverse effect. "The positive benefits of statins, particularly on reducing the risk of heart disease, far outweigh the potential risk of developing neuropathy," lead author David Gaist, MD, PhD, of the University of Southern Denmark in Odense, says in a news release.
In this population-based study, the researchers used a patient registry to identify all first cases of idiopathic peripheral neuropathy in Funen County, Denmark, over a 5-year period. Each case was matched to 25 controls of the same age and sex.
Of 166 cases of first-time idiopathic neuropathy, 35 were classified as definite, 54 as probable and 77 as possible cases. Nine of those diagnosed with neuropathy had taken statins, with an average use duration of 2.8 years. Compared with controls, the statin users had a 14.2-fold risk of developing neuropathy classified as definite, and a 3.7-fold risk of developing neuropathy of any classification.
Those currently using statins had a 16.1-fold risk of definite idiopathic neuropathy and a 4.6-fold risk considering all cases of idiopathic neuropathy. In subjects receiving statins for 2 or more years, risk of developing definite idiopathic neuropathy was 26.4 times that of control patients.
"These findings shouldn’t affect doctor or patient decisions to start using statins," Gaist says, noting that absolute risk of peripheral neuropathy is low. "But if people who take statins develop neuropathy symptoms, they should talk with their doctor, who may reconsider the use of statins."
An accompanying editorial by Michael Donaghy, FRCP, from the University of Oxford, England, highlights unanswered questions: dose-response relationship, risks associated with different statins, and possible compounding effects of additional risk factors.
He applauds the authors for presenting risk data in terms of "number of patients needed to be treated to harm one additional patient." For subjects aged 50 years or older, there was 1 excess case of idiopathic peripheral neuropathy for every 2200 person-years of statin use, which is considerably lower than a comparable estimate of 10,000 for statin myopathy.