Herpes simplex diagnosis and treatment are not associated with incident dementia

• Published in: Alzheimer's & dementia Vol. 17; no. S7; pp. e051898 - n/a
• Main Authors: Schmidt, Mark A, Rawlings, Andreea, Koppulo, Padma D, Prado, Yolanda K, Rosales, A Gabriela, Weinmann, Sheila A
• Format: Journal Article
• Language: English
• Published: United States 01.12.2021
• ISSN: 1552-5260; 1552-5279
• DOI: 10.1002/alz.051898

Background Although an association between dementia and certain infectious diseases, such as HIV, has been well‐established, recent publications have also concerningly hinted at the possibility of its association with a much more common infectious disease, as well: herpes simplex virus (HSV). We sought to better investigate potential associations between HSV diagnosis and treatment with incident dementia in a large, retrospective cohort. Method We conducted our analysis among members of Kaiser Permanente Northwest aged 50 and older between 2000‐2019. We matched individuals with an HSV diagnosis during this time frame to three individuals, each, without HSV, based on age at index date (HSV diagnosis date for cases and a reference date for controls), sex, and membership length prior to index date. Follow‐up time started at the index date and ended on the date of dementia diagnosis, membership end date, death, or end of follow‐up, whichever came first. We defined HSV and dementia diagnoses by ICD‐9/‐10 codes recorded in the electronic health record. We defined herpes simplex antiviral treatment, based on in‐network pharmacy fills. We used survival analysis to examine the associations between dementia with HSV diagnosis (yes/no, overall, by sex, age, and HSV type) and HSV medication fills (yes/no; and by tertiles of medication dispensed). We adjusted models by demographic and clinical factors. Result 87,432 persons (21,661 with HSV) were included. The mean age was 60.9 years and 69% were female. Over a mean follow‐up of 6.1 years, 4,507 developed dementia. HSV diagnoses – overall and Type 2 – was significantly associated with lower risk of dementia (Figure). Anti‐viral medication (any versus none) was not associated with dementia, and we did not see a dose response when examining dose by tertile (Figure). Conclusion In contrast to the recent reports, we found a slight, but statistically‐significant association between HSV diagnosis with dementia. We did not observe a lower risk of dementia associated with anti‐herpetic treatment, also as had been previously reported. The relationship between HSV and dementia may be complex and deserves further study. However, that we did not see a positive association between HSV and dementia in our study is very encouraging.