Three-Year Conversion Rate and Associated Factors of Mild Cognitive Impairment to Dementia in Thai Tertiary Care Outpatient Populations

Background: Dementia is a common neurocognitive disorder associated with aging, causing considerable distress and impairment for both affected individuals and their families. Mild cognitive impairment (MCI) serves as an intermediate stage of cognitive decline between normal aging and dementia, with an increased risk of progressing to dementia. Objective: To explore the three-year conversion rate of MCI to dementia and associated factors in the real-world outpatient setting. Materials and Methods: A retrospective cohort study was carried out by reviewing the out-patient medical records of the patients visiting King Chulalongkorn Memorial Hospital, a Thai tertiary care hospital between 2018 and 2019. Two hundred participants aged 50 years and above with MCI were enrolled and followed for three years. Results: Among recruited participants, the three-year conversion rate was 20%. MCI patients who converted to dementia tended to have a shorter duration since symptoms onset (p=0.005), body mass index (BMI) of less than 23 kg/m² (p=0.039), history of delusion (p=0.003), or hallucination (p=0.010), and were more frequently prescribed antidepressants (p=0.011) and cognitive enhancers (p=0.002). The forward stepwise regression analysis demonstrated that the duration since symptom onset within five years (OR 5.13, 95% CI 1.77 to 14.83, p=0.003), the prescription of cognitive enhancers (OR 5.03, 95% CI 1.05 to 24.02, p=0.043), and antidepressants (OR 3.56, 95% CI 1.22 to 10.42, p=0.020) were the significant predictors for the conversion from MCI to dementia. Conclusion: One out of five participants progressed from MCI to dementia during the three-year follow-up period. The predicted factors included the shorter duration since symptom onset, the prescription of cognitive enhancers, and antidepressants, which represented the cases with more severe cognitive impairment and the presence of clinically significant neuropsychiatric symptoms.