Gender-specific clinical risk scores incorporating blood pressure variability for predicting incident dementia

Dear Editor, We thank Dr. Ser for her detailed reading of our study,1 and starting this important dialogue on the importance of dementia in our aging global population. We fully recognize her point that the use of ICD-9 coding for determining a diagnosis of dementia will lead to an underdiagnosis. Indeed, the cited studies from Canada and Australia illustrate the problem of undercoding specifically on dementia. It is fair to assume that there would be a similar issue for the local data from China. We were not able to identify studies investigating the reliability of coding specifically for dementia in our locality. Nevertheless, based on a local study that calculated the trends of prevalence of dementia in the Hong Kong city based on census data,2 an estimated 100 000 people above the age of 60 suffers from dementia in 2009 and it is projected to increase to approximately 330 000 patients in 2039, which is around 4.7% of the Hong Kong population similar to the incidence rate of 4.74% calculated in our study.