Receiving statin therapy after a concussion may lead to a decreased risk for dementia, according to the findings of a study published in JAMA Neurology.
To investigate whether use of statins is associated with an increase or decrease in the risk for dementia after a concussion in adults, researchers conducted a population-based double cohort study in Ontario, Canada, using data from 1993 to 2013. Participants were aged ≥66 years and had a concussion diagnosis verified using ICD-9 coding. Individuals were excluded from the study cohort if they were admitted to a hospital within 2 days of a concussion, survived less than 90 days, or had a history of dementia or delirium in the prior 5 years. The investigators compared patients who received statins within 90 days after their concussion with those who did not.
During the study, 28,815 individuals (median age 76 years; 61.3% women) were identified as having a diagnosis of concussion. In this group, 7058 individuals (24.5%) received statins within 90 days after a concussion and the other 21,757 individuals (75.5%) did not receive statins.
Over a mean follow-up period of 3.9 years, 4727 individuals developed dementia. Individuals receiving statins accounted for 1050 dementia cases over 28,129 patient-years, equaling 37 annual cases/1000 individuals. The control group accounted for 3677 dementia cases over 85,339 patient-years, which equaled 43 annual cases/1000 individuals.
The use of statins was associated with a 13% decreased risk for dementia (95% CI, 7%-19%; P <.001) compared with individuals who did not receive statins (relative risk, 0.87; 95% CI, 0.81-0.93; P <.001). Rosuvastatin was associated with the highest risk reduction, and simvastatin was associated with the lowest risk reduction. Higher doses of statins were not associated with greater benefits compared with lower doses. Individuals who discontinued statins after the concussion showed no significant risk reduction.
Among the limitations noted for this study was a lack of randomization; therefore, some observed associations could be attributable to the confounding of earlier statin indications. Some covariates such as smoking, physical activity, and drug adherence were missing. Moreover, the study did not have enough power to assess when the benefit of statins occurs (ie, before, during, or after a concussion), and it did not include an examination of individuals with severe brain injury.
“The results of our study suggest that concussions are a common injury in older adults and indicate that dementia may be a frequent outcome years afterward,” wrote the investigators. “A potential neuroprotective benefit may also encourage greater medication adherence for patients who are already prescribed a statin. In addition, a concussion should not be interpreted as a reason to stop statins, and a future randomized trial is justified.”
Redelmeier DA, Manzoor F, Thiruchelvam D. Association between statin use and risk of dementia after a concussion [published online May 20, 2019]. JAMA Neurol. doi:10.1001/jamaneurol.2019.1148