Statin Drugs/NNT Alert

High cholesterol contributes to the furring of the arteries which leads to heart attacks and other major cardiac events. Fortunately, statins prevent the deposit of fatty molecules inside arteries. In some cases, however, unsteadiness in walking has been reported among patients.

Compliance with statin therapy has remained problematic due to the drug’s undesirable side effects.

Myopathy is estimated to occur in 0.5 percent of patients treated with statins during clinical trials, and Rhabdomyolysis in an even smaller portion of users.

Fewer studies have evaluated muscle strength among users, however, so the incidence of weakness, whether related to myopathy or not, may be under-appreciated.

In one study, researchers assessed several patients for proximal muscle weakness after finding they developed proximal weakness with a decline in walking, which reversed after discontinuing the drug.

Writing in the journal of Neuro-rehabilitation and Neural Repair, the authors said: “Unsteadiness in walking, especially on an uneven surface or on changing direction, was the most common complaint.

“[The patients] usually could not pinpoint the onset, but their history of daily activity suggested function changes by six months after the first use of a statin.

“The patients and their physicians did not suspect muscle weakness. They attributed the symptoms to complications of chronic or recent neurological disorders.”

Originally posted April 25, 2014.

If you have been prescribed a statin drug, you will benefit greatly by reading the research presented here, here and here. The concept of NNT, or number needed to treat, offers compelling insight for every patient regardless of the prescribed drug or disease in question.

The harms of statins are less publicized than benefits, but are well documented. A recent narrative review of statin myopathy suggests that 10% is a relatively conservative estimate for this side effect,1 which may be a primary contributor to high rates of drug discontinuation.2 An additional, more concerning side effect is statin-induced diabetes, as noted in the JUPITER study and a large Women’s Health Initiative cohort, studies that best represent primary prevention cohorts.3 We use an absolute risk estimate for statin-induced diabetes with the understanding that this may underestimate risk for many. Baseline risk of diabetes is likely the greatest driver of risk for statin-induced diabetes, and the JUPITER trial enrolled patients at lower risk (2.4%) than many, perhaps most, patients who take statins. Our calculation presumes this low baseline risk and that the aggregate chance of diabetes is time-dependent and linear. We have thus extrapolated from the 1.9-year trial data to a 5-year endpoint, the same time endpoint and calculation used for benefits. These data are relevant to new onset diabetes only, and do not address the equally concerning possibility that some diabetic patients may experience statin-induced worsening of their disease, or inability to manage or cure their disease using lifestyle changes. We look forward to data addressing these issues.

Our sense, based on factors noted above, is that the benefits of these drugs are likely exaggerated partly by an unconscious ‘hope bias’ on the part of readers and authors. This is common in the early literature on therapeutic innovations, and is often attenuated as further literature emerges. In addition, post-marketing surveillance data is in its early stages with this class of drugs and preliminary reports suggest that cognitive decline, tendonopathies, and other side effects may emerge in future literature. Finally, the source of the great majority of these data is industry, which has a spotty history of integrity in trial data reporting, suggesting these data to be a best-case scenario.

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