Subjective cognitive complaints in cognitively normal patients with Parkinson's disease predict development of dementia: A 5-year longitudinal observation.

OBJECTIVE

This study aimed to examine whether subjective cognitive complaints (SCCs) measured by the SCCQ-PD questionnaire can predict the development of dementia in initially cognitively normal patients with Parkinson's disease (PD).

METHODS

We retrospectively analyzed 53 PD patients with normal cognition at baseline who were followed for an average of 5 years. SCCs were assessed using the SCCQ-PD, a self-reported questionnaire, and subjects were classified into three tertile groups based on SCCQ-PD scores (score 0-2, 3-5, and 6-12). Cox proportional hazard models were used to identify predictors of dementia.

RESULTS

Baseline demographic characteristics and cognitive performance did not differ significantly among groups, while patients with high tertile group (SCCQ-PD score 6-12) showed poorer instrumental activities of daily living than those with low tertile group (score 0-2). During follow-up, 17 (32.1 %) patients developed dementia. Patients with the high tertile group were significantly associated with an increased risk of future dementia (adjusted hazard ratio = 5.37; 95 % confidential interval, 1.33-21.67; p = 0.018) after controlling for age and disease duration at baseline.

CONCLUSIONS

SCCs assessed using the SCCQ-PD questionnaire may be associated with an increased risk of future dementia in cognitively normal patients with PD. Prospective validation in larger cohorts is required to confirm the predictive value of the SCCQ-PD.