Incidence of Postoperative Cognitive Decline in Surgical Patients With Preexisting Cognitive Impairment: A Prospective Cohort Study
Conditions: Cognitive and Behavioral Impairment
Sponsor: Peking University Shenzhen Hospital

Cover page 
 
Official Title: 
Incidence of Postoperative Cognitive Decline in Surgical Patients 
With Preexisting Cognitive Impairment: A Prospective Cohort Study 
ClinicalTrials.gov Identifier (NCT Number): 
 
Document Type: 
Study Protocol 
Version Number: 
No.1 
Version Date: 
May 4, 2025 
Principal Investigator: 
[Yaqian Yu, MN] 
[Department of Operating room, Peking University Shenzhen 
Hospital] 
Sponsor: 
Peking University Shenzhen Hospital 
 
 

Official Title: 
Incidence of Postoperative Cognitive Decline in Surgical Patients 
With Preexisting Cognitive Impairment: A Prospective Cohort Study 
1. Background  
Cognitive impairment is prevalent among the elderly population, 
with increasing rates as global aging accelerates. Preexisting cognitive 
impairment (PreCI) in surgical patients is associated with a higher 
incidence of postoperative cognitive decline (POCD), delirium, hospital 
readmission, and mortality. However, data regarding the incidence of 
POCD in Chinese patients with PreCI undergoing elective non-cardiac 
surgery under general anesthesia is currently lacking. This study aims to 
fill this evidence gap by prospectively investigating the incidence of 
POCD in this patient population. 
2. Objectives 
Primary Objective: 
To determine the incidence of postoperative cognitive decline 
(POCD) at 3 months after surgery in elderly patients (≥60 years) with 
preexisting cognitive impairment undergoing elective non-cardiac surgery 
under general anesthesia. 
Secondary Objectives: 
To evaluate the incidence of POCD at 12 months postoperatively. 
 

To assess neuropsychiatric symptoms (NPI-Q), functional abilities 
(BADL, IADL), and dementia severity (CDR) at 3 and 12 months 
postoperatively. 
3. Study Design 
A single-center, prospective, single-arm cohort study with a 
normative comparison group for RCI-based incidence calculation.PreCI 
Surgical Group: Elderly patients with cognitive impairment undergoing 
elective general anesthesia non-cardiac surgery. Normative Comparison 
Group: Cognitively normal elderly subjects for reference data of natural 
cognitive change over time. 
4. Study Population 
Inclusion Criteria (PreCI Group): 
-Age ≥ 60 years 
-Diagnosed as having mild cognitive impairment or mild dementia 
by MMSE and MoCA-B screening 
-Scheduled for elective non-cardiac surgery under general anesthesia 
Exclusion Criteria: 
-Expected difficulty in neuropsychological assessment (e.g., severe 
hearing/visual impairments, language barrier) 
-Residence outside Shenzhen 
Normative Comparison Group: 
-Age ≥ 60 years 

-No history of general anesthesia surgery within the past 12 months 
-Mini-Cog score > 1 
Exclusion Criteria: 
-Planned elective surgery under general anesthesia within the next 
12 months 
-History of suspected or diagnosed cognitive impairment, or 
screening indicating cognitive impairment using MMSE and MoCA-B 
-Expected difficulty in completing neuropsychological assessments 
(e.g., inability to communicate in Mandarin, blindness, or deafness) 
-Usual residence outside Shenzhen 
5. Outcome Measures 
Primary Outcome: 
Incidence of POCD at 3 months postoperatively, defined using the 
Reliable Change Index (RCI) methodology. 
Secondary Outcomes: 
Incidence of POCD at 12 months 
NPI-Q, BADL, IADL, and CDR scores at 3 and 12 months 
6. Assessment Tools 
Mini-Cog 
MMSE 
MoCA-B 
NPI-Q 

CDR 
BADL, IADL 
7. Sample Size Estimation 
PreCI group: 252 patients (accounting for 15% attrition, based on 
estimated 14.9% POCD incidence at 3 months) 
Normative group: 88 participants (allowing for 15% attrition) 
8. Statistical Analysis Plan (SAP) 
8.1 Descriptive Analysis: 
Continuous variables will be expressed as mean ± SD or median 
(IQR) as appropriate. Categorical variables will be presented as 
frequencies and percentages. 
8.2 Incidence of POCD: 
POCD defined by RCI ≤ -1.96 in at least two cognitive domains 
or composite Z-score ≤ -1.96. 
Frequencies and percentages reported at each follow-up time point. 
Subgroup analysis based on surgery type, anesthesia type, baseline 
cognitive scores. 
Intention-to-treat (ITT) analysis applied. 
8.3 Handling of Missing Data: 
Missing data imputed using multiple imputation techniques. 
Sensitivity analyses conducted to evaluate robustness of results. 
 

8.4 Adjustment for Confounding: 
Multivariable logistic regression used to adjust for potential 
confounders: age, sex, education, comorbidities, surgery type. 
8.5 Statistical Software: 
All analyses performed using R software  
9. Data Management 
Data recorded via electronic and paper CRFs. Regular data 
monitoring, double data entry, and periodic audits to ensure data quality. 
10. Ethics and Informed Consent 
Study approved by the Ethics Committee of Peking University 
Shenzhen Hospital. Written informed consent obtained from all 
participants or their legal representatives before enrollment. 
11. Publication Plan 
Results will be published in peer-reviewed journals and presented at 
relevant academic conferences.