Comment on “The association between cognitive function trajectories and all-cause mortality in middle-aged and older Chinese adults with cardiovascular disease: A longitudinal study from CHARLS”

Dear Editor,

We read with great interest the study by Song et al. examining cognitive function trajectories and all-cause mortality among adults with cardiovascular disease (CVD) using data from the China Health and Retirement Longitudinal Study [1]. The trajectory-based perspective provides a valuable extension beyond conventional baseline cognitive assessment.

The authors do not appear to have considered the potential constraints of deriving cognitive trajectories from only three assessment points. Although the use of longitudinal K-means clustering with dynamic time warping is methodologically sophisticated, limited temporal sampling may reduce the stability of trajectory classification and increase susceptibility to short-term cognitive fluctuation [2]. This approach may limit the precision with which sustained cognitive decline can be distinguished from transient change, thereby influencing mortality risk estimation. Additional follow-up waves or external validation could strengthen confidence in these trajectory patterns.

Moreover, reliance on a global cognitive composite score may mask clinically meaningful heterogeneity across cognitive domains. Domains such as attention and temporal orientation appeared to contribute disproportionately to rapid decline, yet their influence may be diluted when aggregated with less sensitive components. This may limit clinical applicability, as cognitive screening and intervention are often guided by domain-specific impairment. Future analyses focusing on domain-level trajectories may enhance translational relevance.

Finally, the stronger associations observed among participants with hypertension emphasize the importance of heart–brain interactions in CVD populations. Further integration of longitudinal vascular profiles may clarify whether adverse cognitive trajectories reflect cumulative vascular burden or represent an independent prognostic signal.

These considerations may help refine trajectory-based cognitive risk stratification in cardiovascular care.

CRediT authorship contribution statement

Palavardhan Peddapalegani: Validation, Writing – original draft, Writing – review & editing. Raghav Gupta: Project administration, Supervision, Writing – original draft, Writing – review & editing. Priyanka Bansal: Conceptualization, Methodology, Writing – original draft, Writing – review & editing. Pankaj Nainwal: Writing – original draft, Writing – review & editing. Hariharan Srinivasan: Writing – original draft, Writing – review & editing.