To the Editor We read with interest the article by Zissimopoulos et al1 that found that Alzheimer disease (AD) risk was 10% lower among Medicare beneficiaries exposed to higher levels of statins compared with lower levels of statins. While the authors have designed the study to address certain biases, we are concerned that they overlooked other potential biases in ascertaining AD after the submission of Medicare claims for statins that may have contributed to the lower observed incidence among people using high levels of statins.
Freedman DM, Pfeiffer RM. Ascertainment Bias in Statin Use and Alzheimer Disease Incidence. JAMA Neurol. Published online May 01, 2017. doi:10.1001/jamaneurol.2017.0427