Within 30 days of first taking statin and nonstatin lipid-lowering drugs (LLDs), patients were more likely have memory loss compared with a group that was not treated with any LLDs, according to a retrospective cohort study. When comparing statin and nonstatin users, there was no difference in memory loss.

However, lead researcher Brian L. Strom, MD, MPH, of Rutgers University in Newark, N.J., and colleagues said they were unsure if LLDs caused memory loss. They mentioned that patients taking the drugs might have been more likely to have their memory loss detected because they saw their physicians more often.

Still, memory loss was not common in any group. Within 30 days of first exposure, memory loss was found in 0.08 percent of statin users, 0.07 percent of nonstatin LLD users and 0.02 percent of nonusers of any LLD.

Results were published online in JAMA Internal Medicine on June 8.

To determine the association between statin use and acute memory impairment, the researchers examined The Health Improvement Network, a database that includes medical records from general practitioners in the United Kingdom. They analyzed data on nearly 11 million patients from 553 practices that was available from Jan. 13, 1987 to Dec. 16, 2013.

Patients with a history of cognitive dysfunction were excluded, as were those who received medications used to treat dementia.

Strom et al examined 482,543 patients who received statins and the same number of patients who did not take any LLD. They also evaluated 26,484 patients who took nonstatin LLDs.

They assessed acute, reversible, memory impairment by using diagnostic codes for memory loss terms such as amnesia, amnesia symptoms, memory loss symptoms, temporary loss of memory and memory lapses.

The baseline characteristics of statin users and nonusers were similar because they were matched. The mean age was approximately 63, and 54 percent of patients in each group were male.

However, 63.4 percent of patients in the statin group and 57.3 percent of patients in the nonstatin LLD group were older than 60 years old, which represented a statistically significant difference. Patients who used nonstatin LLDs were also more likely to have diabetes, hypercholesterolemia and cardiovascular disease compared with statin users.

During the 30 days after patients first received statins, they were significantly more likely to have acute, reversible memory impairment compared with the nonusers of LLDs.

Of the patients who received statins, 75.2 percent were prescribed simvastatin.

“The observation that all LLDs were associated with memory loss leads to the conclusion that either all LLDs cause acute memory loss regardless of drug class or that the association is the result of bias … rather than a causal association,” the researchers wrote. “Given the heterogeneity of molecular structures among the LLDs, the latter may be more likely, but we cannot confirm this hypothesis using these data.”