Ann Dermatol.  2020 Apr;32(2):115-121. 10.5021/ad.2020.32.2.115.

Validity of Diagnostic Codes for Identification of Psoriasis Patients in Korea

Affiliations
  • 1Department of Dermatology, Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea. stratum@paik.ac.kr
  • 2Department of Dermatology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.
  • 3Department of Dermatology, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea.
  • 4Department of Dermatology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.
  • 5Department of Dermatology, Seoul Paik Hospital, Inje University College of Medicine, Seoul, Korea.

Abstract

BACKGROUND
Recently, the number of nationwide medical researches on psoriasis using the National Health Insurance Service database has been on the rise. However, identification of psoriasis using diagnostic codes alone can lead to misclassification. Accuracy of the diagnostic codes and their concordance with medical records should be validated first to identify psoriasis patients correctly.
OBJECTIVE
To validate the diagnostic codes of psoriasis (International Classification of Diseases, 10th Revision L40) and to find the algorithm for the identification of psoriasis.
METHODS
We collected medical records of patients who received their first diagnostic codes of psoriasis during 5 years from five hospitals. Fifteen percent of psoriasis patients were randomly selected from each hospital. We performed a validation by reviewing medical records and compared 5 algorithms to identify the best algorithm.
RESULTS
Total of 538 cases were reviewed and classified as psoriasis (n=368), not psoriasis (n=159), and questionable (n=11). The most accurate algorithm was including patients with ≥1 visits with psoriasis as primary diagnostic codes and prescription of vitamin D derivatives. Its positive predictive value was 96.5% (95% confidence interval [CI], 93.9%~98.1%), which was significantly higher than those of the algorithm, including patients with ≥1 visits with psoriasis as primary diagnostic codes or including ≥1 visits with diagnostic codes of psoriasis (primary or additional) (91.0% and 69.8%). Sensitivity was 90.8% (95% CI, 87.2%~93.4%) and specificity was 92.5% (95% CI, 86.9%~95.9%).
CONCLUSION
Our study demonstrates a validated algorithm to identify psoriasis, which will be useful for the nationwide population-based study of psoriasis in Korea.

Keyword

Electronic medical record; International Classification of Disease Codes; National Health Insurance; Psoriasis

MeSH Terms

Classification
Electronic Health Records
Humans
International Classification of Diseases
Korea*
Medical Records
National Health Programs
Prescriptions
Psoriasis*
Sensitivity and Specificity
Vitamin D
Vitamin D

Figure

  • Fig. 1 Flow chart of study population selection. Total 3,587 patients with psoriasis diagnostic codes were included. Random samples of 538 cases were collected (15% of total cases from each hospital). After the review, 368 (68.4%) were psoriasis, 159 (29.6%) were not psoriasis, and 11 (2.0%) were questionable to diagnosis. ICD: International Classification of Diseases.


Reference

1. Parisi R, Symmons DP, Griffiths CE, Ashcroft DM. Identification and Management of Psoriasis and Associated ComorbidiTy (IMPACT) Project Team. Global epidemiology of psoriasis: a systematic review of incidence and prevalence. J Invest Dermatol. 2013; 133:377–385. PMID: 23014338.
Article
2. Wilchesky M, Tamblyn RM, Huang A. Validation of diagnostic codes within medical services claims. J Clin Epidemiol. 2004; 57:131–141. PMID: 15125622.
Article
3. Kim ES, Han K, Kim MK, Park YM, Baek KH, Moon SD, et al. Impact of metabolic status on the incidence of psoriasis: a Korean nationwide cohort study. Sci Rep. 2017; 7:1989. PMID: 28512338.
Article
4. Han JH, Lee JH, Han KD, Seo HM, Bang CH, Park YM, et al. Epidemiology and medication trends in patients with psoriasis: a nationwide population-based cohort study from Korea. Acta Derm Venereol. 2018; 98:396–400. PMID: 29265167.
Article
5. Lee JY, Kang S, Park JS, Jo SJ. Prevalence of psoriasis in Korea: a population-based epidemiological study using the Korean National Health Insurance Database. Ann Dermatol. 2017; 29:761–767. PMID: 29200766.
Article
6. Park BJ, Suh SW, Sung JH, Park GD, Kim SH. Improvement plan for validity of health insurance disease code and establishment of data application plan. Seoul: Health Insurance Review Agency Research Service;2003.
7. Lee MS, Yeh YC, Chang YT, Lai MS. All-cause and cause-specific mortality in patients with psoriasis in Taiwan: a nationwide population-based study. J Invest Dermatol. 2017; 137:1468–1473. PMID: 28257796.
8. Löfvendahl S, Theander E, Svensson Å, Carlsson KS, Englund M, Petersson IF. Validity of diagnostic codes and prevalence of physician-diagnosed psoriasis and psoriatic arthritis in southern Sweden--a population-based register study. PLoS One. 2014; 9:e98024. PMID: 24875275.
9. Ahlehoff O, Gislason GH, Jørgensen CH, Lindhardsen J, Charlot M, Olesen JB, et al. Psoriasis and risk of atrial fibrillation and ischaemic stroke: a Danish nationwide cohort study. Eur Heart J. 2012; 33:2054–2064. PMID: 21840930.
Article
10. Trevethan R. Sensitivity, specificity, and predictive values: foundations, pliabilities, and pitfalls in research and practice. Front Public Health. 2017; 5:307. PMID: 29209603.
Article
11. Parikh R, Mathai A, Parikh S, Chandra Sekhar G, Thomas R. Understanding and using sensitivity, specificity and predictive values. Indian J Ophthalmol. 2008; 56:45–50. PMID: 18158403.
Article
12. Hawass NE. Comparing the sensitivities and specificities of two diagnostic procedures performed on the same group of patients. Br J Radiol. 1997; 70:360–366. PMID: 9166071.
Article
13. Raghupathi W, Raghupathi V. Big data analytics in healthcare: promise and potential. Health Inf Sci Syst. 2014; 2:3. PMID: 25825667.
Article
14. Kim JA, Yoon S, Kim LY, Kim DS. Towards actualizing the value potential of Korea Health Insurance Review and Assessment (HIRA) data as a resource for health research: strengths, limitations, applications, and strategies for optimal use of HIRA data. J Korean Med Sci. 2017; 32:718–728. PMID: 28378543.
Article
15. Kim L, Kim JA, Kim S. A guide for the utilization of Health Insurance Review and Assessment service national patient samples. Epidemiol Health. 2014; 36:e2014008. PMID: 25078381.
Article
16. Cheol Seong S, Kim YY, Khang YH, Heon Park J, Kang HJ, Lee H, et al. Data resource profile: the national health information database of the National Health Insurance Service in South Korea. Int J Epidemiol. 2017; 46:799–800. PMID: 27794523.
Article
17. Huerta C, Rivero E, Rodríguez LA. Incidence and risk factors for psoriasis in the general population. Arch Dermatol. 2007; 143:1559–1565. PMID: 18087008.
Article
18. Seminara NM, Abuabara K, Shin DB, Langan SM, Kimmel SE, Margolis D, et al. Validity of The Health Improvement Network (THIN) for the study of psoriasis. Br J Dermatol. 2011; 164:602–609. PMID: 21073449.
Article
19. Icen M, Crowson CS, McEvoy MT, Gabriel SE, Maradit Kremers H. Potential misclassification of patients with psoriasis in electronic databases. J Am Acad Dermatol. 2008; 59:981–985. PMID: 18835060.
Article
20. Asgari MM, Wu JJ, Gelfand JM, Salman C, Curtis JR, Harrold LR, et al. Validity of diagnostic codes and prevalence of psoriasis and psoriatic arthritis in a managed care population, 1996-2009. Pharmacoepidemiol Drug Saf. 2013; 22:842–849. PMID: 23637091.
Article
21. Oh EH, Ro YS, Kim JE. Epidemiology and cardiovascular comorbidities in patients with psoriasis: a Korean nationwide population-based cohort study. J Dermatol. 2017; 44:621–629. PMID: 28191654.
Article
22. Ahlehoff O, Gislason GH, Charlot M, Jørgensen CH, Lindhardsen J, Olesen JB, et al. Psoriasis is associated with clinically significant cardiovascular risk: a Danish nationwide cohort study. J Intern Med. 2011; 270:147–157. PMID: 21114692.
Article
Full Text Links
  • AD
Actions
Cited
CITED
export Copy
Close
Share
  • Twitter
  • Facebook
Similar articles
Copyright © 2024 by Korean Association of Medical Journal Editors. All rights reserved.     E-mail: koreamed@kamje.or.kr