OBJECTIVE: Mild cognitive impairment (MCI) usually represents a transitional phase between normal cognitive function and dementia, but not all people with MCI develop dementia because MCI is a clinically and etiologically heterogeneous grouping. The aim of this study was to determine whether clinical subtypes of MCI and severity of white matter hyperintensities (WMH) were associated with progression of MCI to dementia. METHOD: Our study cohort consisted of 840 patients aged 55 years or older who had a diagnosis of MCI at their baseline visit and had at least one follow-up contact after baseline. RESULTS: The results of the multivariable Cox proportional hazards model analysis revealed that both multiple domain amnestic MCI with WMH and multiple domain amnestic MCI without WMH were a significantly more likely to progress to dementia in comparison with patients with non-amnestic MCI. Logistic regression analyses showed that PWMH (periventricular white matter hyperintensities), not the deep white matter hyperintensities, was significantly associated with incident dementia. CONCLUSIONS: This study showed that mdMCI + a (-NL or -WMH) are more associated with progression to dementia. We also found that increasing severity of PWMH, not deep white matter hyperintensities, was significantly associated with incident dementia, independently of subtype of MCI. It suggests that both mdMCI + a and PWMH are good prognostic factors of progression to dementia in MCI.
OBJECTIVE: Mild cognitive impairment (MCI) usually represents a transitional phase between normal cognitive function and dementia, but not all people with MCI develop dementia because MCI is a clinically and etiologically heterogeneous grouping. The aim of this study was to determine whether clinical subtypes of MCI and severity of white matter hyperintensities (WMH) were associated with progression of MCI to dementia. METHOD: Our study cohort consisted of 840 patients aged 55 years or older who had a diagnosis of MCI at their baseline visit and had at least one follow-up contact after baseline. RESULTS: The results of the multivariable Cox proportional hazards model analysis revealed that both multiple domain amnestic MCI with WMH and multiple domain amnestic MCI without WMH were a significantly more likely to progress to dementia in comparison with patients with non-amnestic MCI. Logistic regression analyses showed that PWMH (periventricular white matter hyperintensities), not the deep white matter hyperintensities, was significantly associated with incident dementia. CONCLUSIONS: This study showed that mdMCI + a (-NL or -WMH) are more associated with progression to dementia. We also found that increasing severity of PWMH, not deep white matter hyperintensities, was significantly associated with incident dementia, independently of subtype of MCI. It suggests that both mdMCI + a and PWMH are good prognostic factors of progression to dementia in MCI.