A Retrospective Review on Charlson Comorbidity Index (CCI) as a Predictor of Return-of-spontaneous-circulation and Survival-to-discharge of Geriatric In-hospital Cardiopulmonary Resuscitation (CPR) in a Regional Acute Hospital in Hong Kong
Conditions: Comorbidities and Coexisting Conditions, Cardiopulmonary Resuscitation, Geriatrics
Sponsor: Jane Yidan Zhu

A retrospective review on Charlson Comorbidity Index as 
a predictor of return-of-spontaneous-circulation and 
survival-to-discharge of geriatric in-hospital 
cardiopulmonary resuscitation in a regional acute hospital 
in Hong Kong 
 
Jane Yidan Zhu1, Shu Hong Wah1, Kam Ngai Kung2 
 
1 JY Zhu, MBBS, FHKCP 
1 SH Wah, MBChB, FHKCP 
2 KN Kung, MBChB, FHKCP 
1 Department of Medicine, Haven of Hope Hospital, Hong Kong 
2 Department of Medicine & Geriatrics, United Christian Hospital, Hong Kong 
 
Word count 
Abstract: 250 words 
Manuscript: 2792 words (4500 words including References and Tables) 
Document date: 16 May, 2023 

Method 
Inclusion and exclusion criteria 
This retrospective review included all adults aged 65 or above with in-hospital cardiac arrest 
and undergoing CPR in wards of Department of Medicine and Geriatrics (excluding Intensive 
Care Unit (ICU)) in United Christian Hospital (total bed 1,174 with 16 ICU beds) in Hong Kong 
from 1 January 2017 to 31 December 2018. It was approved by Kowloon Central and 
Kowloon East Cluster Research Ethics Committee (KC/KE-18-0283/ER-1).  In patients with 
multiple resuscitation events, only the first in-hospital CPR was included. The primary 
outcome was ROSC; survival 24 hours after first CPR, on discharge, and at 1 year. 
 
The exclusion criteria are as follows: patients with existing Do-Not-Attempt-
Cardiopulmonary-Resuscitation (DNACPR) order, patients younger than 65 years old, out-of-
hospital CPR in the index admission, CPR occurred in ICU / Emergency Department / 
Operating Theatre / wards other than medical wards. 
 
Definitions 
Cardiopulmonary arrest is defined as sudden cessation of spontaneous circulation and 
respiration leading to loss of consciousness and necessitating CPR. Sustained ROSC is 
defined as documented return of adequate circulation in the absence of ongoing chest 
compressions, and the duration should be of 20 minutes or above.14 CCI was calculated 
according to the International Classification of Disease, Tenth Revision, Clinical Modification 
(ICD-10) coding.  

Data collection and categorization 
Eligible patients were identified by the CPR records (which contained the name and hospital 
number of each patient undergoing CPR) on the emergency trolley in each ward. The case 
notes and electronic patient records of these patients were reviewed.  
 
Other covariates include smoking status, premorbid activity of daily living (ADL), premorbid 
mobility, the source of patient (home vs old aged home), tube feeding, any use of 
anticoagulation, post-operative status. Post-operative status was defined as any operations 
(including percutaneous coronary intervention (PCI)) within 30 days prior to cardiac arrest. 
Survival was measured at 24 hours, on hospital discharge, and at 1 year. 
 
The details of CPR were collected according to Utstein style from resuscitation records in 
case notes. Shift of the day was defined according to nurses’ schedule. Dayshift was defined 
as 7am to 9:30pm, and nightshift was defined as 9:30pm to 7am the next day. 
 
Proportion of patient transferral to Intensive Care Unit/Coronary Care Unit after ROSC was 
recorded. Pre-discharge mobility, ADL and discharge destination in survived patients were 
also charted.  
 
 
 

Statistical Method 
SPSS version for Windows (version 25; IBM Corp, Armonk [NY], United States) software was 
used for statistical analysis. For the association between outcome (ROSC and survival-to-
discharge) and categorical independent variables, Chi-squared test and Fisher’s exact test 
were used. For continuous independent variables, student’s t test was used for normally 
distributed data and Mann-Whitney U test was used for non-parametric data. CCI was 
categorized into three groups: 0-3, 4-6, ≥7. Chi-squared test was used to assess the 
differences between the above CCI groups. A two-tailed p value of <0.05 was considered 
statistically significant. Missing data were handled with SPSS’s listwise deletion option.