This study aims to find out how often memory and thinking problems happen after surgery in people who already have memory issues before their operation. These memory problems are called postoperative cognitive decline (POCD). Older adults with memory problems before surgery may be more likely to have trouble with thinking, memory, and daily activities after their operation. This study will follow patients who already have memory problems before surgery and see how their thinking and memory change after surgery. The results will help doctors better understand how to care for these patients before, during, and after surgery.
Preexisting Cognitive Impairment (PreCI) Surgical Group
Age ≥ 60 years
Preoperative screening with MMSE and MoCA-B indicating mild cognitive impairment (MCI) or mild dementia
Undergoing elective non-cardiac surgery under general anesthesia
Expected difficulty in completing neuropsychological assessments (e.g., inability to communicate in Mandarin, blindness, or deafness)
Usual residence outside Shenzhen
Normative Reference Group
Age ≥ 60 years
Patients aged 60 years and older with preexisting cognitive impairment undergoing elective non-cardiac surgery under general anesthesia at Peking University Shenzhen Hospital will be recruited between June 2025 and December 2027. A normative reference group of cognitively normal elderly individuals, matched by age and sex, will also be enrolled from the same hospital during the same period. All participants must reside in Shenzhen and be able to communicate in Mandarin.
Cohort
Prospective
surgery
Procedure/SurgeryPatients with preexisting cognitive impairment undergoing elective non-cardiac surgery under general anesthesia.
norma
Other interventionCognitively normal individuals who do not undergo surgery but complete the same cognitive assessments at baseline, 3 months, and 12 months for normative reference.
Incidence of Postoperative Cognitive Decline (POCD) at 3 Months
The primary outcome is the incidence of objectively measurable postoperative cognitive decline (POCD) at 3 months in patients with preexisting cognitive impairment undergoing elective non-cardiac surgery under general anesthesia. The diagnosis of POCD will follow the nomenclature recommendations by Evered et al., which define POCD as cognitive decline occurring between 3 months and 7.5 years after surgery, determined by standardized score changes compared with a normative reference population. In this study, POCD will be identified using the Reliable Change Index (RCI), calculated as: RCI = (ΔX\_patient - Δμ\_normative) / σ\_normative A patient will be diagnosed with POCD if: At least two cognitive domains show an RCI ≤ -1.96, or The combined Z-score of all cognitive tests is ≤ -1.96.
Incidence of POCD at 12 Months
Incidence of objectively measurable POCD at 12 months postoperatively, assessed using the same criteria as the primary outcome (RCI method).
Neuropsychiatric Symptoms Assessed by NPI-Q
Neuropsychiatric symptoms will be evaluated using the Neuropsychiatric Inventory-Questionnaire (NPI-Q), based on caregiver or informant reports. It assesses the presence, severity, and caregiver distress associated with 12 neuropsychiatric symptoms commonly seen in patients with cognitive impairment. For each symptom, severity is rated on a scale from 1 to 3 (1 = mild, 2 = moderate, 3 = severe), with a total severity score ranging from 0 to 36. Higher scores indicate more severe neuropsychiatric symptoms.
Functional Ability Assessed by The Barthel Index
The Barthel Index (BI) in an informant report was used for measuring basic ADL actual performance in this study. The BI is a questionnaire that consists of ten items: feeding, bathing, grooming, dressing, bowels, bladder, toilet use, transfer, mobility, and stairs. The summary score ranges from 0 to 100, with lower scores indicating a poorer basic ADL performance
Dementia Severity Assessed by CDR
The Clinical Dementia Rating (CDR) will be used to assess the severity of dementia by evaluating six cognitive and functional domains. Scores range from 0 (no impairment) to 3 (severe dementia). CDR scores will be recorded at each follow-up.
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