Statin use associated with dementia risk reduction after concussion in older adults
Concussion is associated with a substantial long-term risk of dementia in older adults, but the risk can be reduced modestly with the use of statins, a large population-based double cohort study has shown.
In the study, older adults (age, ≥66 years) diagnosed as having a concussion throughout Ontario, Canada, were enrolled between 1993 and 2013. The survivors were followed up until 2016 – for a minimum of 3 years and a maximum of 20 years. [JAMA Neurol 2019, doi: 10.1001/jamaneurol.2019.1148]
Among 28,815 patients with a concussion (median age, 76 years; 61.3 percent female), 4,727 patients subsequently developed dementia during a mean follow-up period of 3.9 years. The absolute incidence of dementia was 1 case per 6 patients.
Based on the Ontario Drug Benefit Program database, 7,058 patients (24.5 percent) with a concussion received a statin within 90 days after a concussion. Compared with the 21,757 patients (75.5 percent) who did not receive a statin, statin recipients had a 13 percent reduction in risk of dementia (relative risk, 0.87; 95 percent confidence interval, 0.81 to 0.93; p<0.001), with a number needed to treat of about 50.
Among statin recipients, the incidence of dementia was 37 cases per 1,000 patients annually (ie, twice the population norm). In comparison, the incidence of dementia among patients who did not receive a statin was 43 cases per 1,000 patients annually (ie, more than twice the population norm).
“The decreased risk of dementia associated with statin use applied to diverse patient groups, remained independent of other cardiovascular medication use, intensified over time, was distinct from the risk of subsequent depression, and was not observed in patients after an ankle sprain [ie, secondary parallel analysis],” the investigators reported.
In addition, the relative reduction in dementia risk associated with statin use after a concussion was greatest for patients taking rosuvastatin, consistent for patients receiving lower dosages, accentuated after adjustments for measured patient characteristics, and distinct from the risks for patients after an ankle sprain.
“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 afterwards,” the investigators commented. “More efforts to prevent concussion should be encouraged at all ages. Screening for past concussions may also offer new clinical insights for patients diagnosed with dementia.”
“For patients already prescribed a statin, a potential neuroprotective benefit may encourage increased medication adherence. In addition, a concussion should not be interpreted as a reason to stop statins,” they added.According to the investigators, the study adds to the current body of evidence on statin use after traumatic brain injury due to its larger sample size, longer follow-up, more detailed statistical analysis, and a priority on concussions. Patients with severe concussion resulting in hospitalization, those with a prior diagnosis of dementia or delirium, and those who died within 90 days were excluded.