ICD-9 codes underestimate statin-linked rhabdomyolysis

<i>ICD-9</i> codes underestimate statin-Linked rhabdomyolysis

(HealthDay) -- Use of diagnostic codes, such as International Classification of Diseases -- Ninth Revision (ICD-9) codes, may result in misclassification of rare, adverse drug reactions (ADRs), including the risk of rhabdomyolysis from high-dose simvastatin, according to a research letter published in the April 18 issue of the Journal of the American Medical Association, a theme issue on comparative effectiveness research.

To assess the use of diagnostic codes as a method of estimating statin-related rhabdomyolysis and myopathy, James S. Floyd, M.D., of the University of Washington in Seattle, and colleagues reviewed the full for patients from the Group Health Cooperative who had a statin prescription within three months of an ICD-9 code for rhabdomyolysis or an ADR.

The researchers found that among the 292 statin users with an ICD-9 code for rhabdomyolysis, 29 cases were identified and validated. None of the 29 cases died; 90 percent were hospitalized and 29 percent had at least a doubling of serum creatinine levels. Using the ICD-9 code, the rhabdomyolysis incidence rate ratio (IRR) for simvastatin versus other statins was 2.61 versus 1.03. For a dose of simvastatin of 80 mg per day or greater versus 20 to 39 mg per day, the IRR was 12.2 for validated cases and 1.77 using the ICD-9 code for rhabdomyolysis.

"These results confirm in a community setting findings from a recent clinical trial that prompted the U.S. to issue a warning about the use of high-dose simvastatin," the authors write. "The ICD-9 code for rhabdomyolysis was nonspecific for this ADR, and the resulting misclassification markedly attenuated the estimated relative risk for high-dose versus low-dose simvastatin."

One of the authors disclosed to the medical device/technology industries.

More information: Abstract
Full Text (subscription or payment may be required)

Related Stories

FDA announces new limits on high-dose simvastatin (Zocor)

date Jun 09, 2011

The United States Food and Drug Administration (FDA) today announced new limitations to the use of high-dose simvastatin, due to the increased risk of muscle pain and weakness (myopathy) and in rare cases, kidney damage and ...

Recommended for you

FDA clears drug for leading form of cystic fibrosis

date Jul 02, 2015

Federal health officials have approved a new combination drug for the most common form of cystic fibrosis, the debilitating inherited disease that causes internal mucus buildup, lung infections and early death. But it will ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.