https://orcid.org/0000-0002-5611-1637
![Sample our Medicine, Dentistry, Nursing & Allied Health journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/5944/TOC-Subject-Sample-2021-Medicine-Dentistry-Nursing-Allied-Health.jpg"})
Abstract
Background
Electronic health record (EHR) databases can facilitate epidemiology research into various diseases including asthma. Given the diagnostic challenges of asthma, the validity of the coding in EHR requires clarification. We aimed to assess the validity of International Classification of Diseases, 9th Revision (ICD-9) code algorithms for identifying asthma in the territory-wide electronic medical health record system of the Clinical Data Analysis and Reporting System (CDARS) in Hong Kong.
Methods
Adult patients who had the diagnosis of asthma input from all public hospitals in Hong Kong and those from Queen Mary Hospital in 2011–2020 were identified using the ICD-9 code of 493 (493.0, 493.1, 493.2, and 493.9) by CDARS. Patients’ clinical record and spirometry were reviewed by two respiratory specialists to confirm the presence of asthma in the randomly selected cases.
Results
There were 43,454 patients who had the diagnostic code of asthma among all public hospitals in Hong Kong and 1852 in Queen Mary Hospital in the same period. A total of 200 cases were randomly selected and validated using medical record and spirometry review by a respiratory specialist. The overall positive predictive value (PPV) was 85.0% (95% CI 80.1−89.9%).
Conclusion
This was the first ICD-9 code validation for CDARS (EHR) in Hong Kong on asthma. Our study demonstrated that using ICD-9 code (493.0, 493.1, 493.2 and 493.9) to identify asthma can result in a PPV that was reliable to support the utility of the CDARS database for further research on asthma among the Hong Kong population.
Abbreviations
ACO, asthma–chronic obstructive pulmonary disease overlap; CDARS, Clinical Data Analysis and Reporting System; CI, confidence interval; COPD, chronic obstructive pulmonary disease; EHR, electronic health record; ePR, electronic patient record; HKHA, Hong Kong Hospital Authority; ICD-9, International Classification of Diseases, 9th Revision; ISAAC, International Study of Asthma and Allergy in Childhood; IQR, interquartile range; PPV, positive predictive value; QMH, Queen Mary Hospital; SD, standard deviation.
Ethics Approval and Informed Consent
The study was approved by the Institutional Review Board of the University of Hong Kong and Hospital Authority Hong Kong West Cluster (UW 22-559). The requirement for informed consent is waived by the IRB. Patient consent was waived in this retrospective study by IRB of the University of Hong Kong and Hospital Authority Hong Kong West Cluster as it is a retrospective study without active patient recruitment while the data were already deidentified. The study was conducted in compliance with the Declaration of Helsinki. Patient data were maintained with confidentiality throughout the study.
Author Contributions
All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis, and interpretation, or in all these areas; took part in drafting, revising, or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.
Disclosure
Dr Esther Wai Yin Chan reports grants from Food and Health Bureau of the Government of the Hong Kong SAR, Research Grants Council, Hong Kong SAR, National Natural Science Fund of China, RGA Reinsurance Company, Amgen, and Narcotics Division of the Security Bureau of the Government of the Hong Kong SAR; grants, personal fees from AstraZeneca, Novartis, and Pfizer; personal fees from Hospital Authority, Hong Kong SAR, outside the submitted work. The authors report no other conflicts of interest in this work.