Validity of diagnostic codes and prevalence of psoriasis and psoriatic arthritis in a managed care population, 1996-2009

UMMS Affiliation

Meyers Primary Care Institute; Department of Medicine, Division of Rheumatology; Department of Orthopedics and Physical Rehabilitation



Document Type


Medical Subject Headings

Psoriasis; Arthritis, Psoriatic; Prevalence


Clinical Epidemiology | Dermatology | Health Services Research | Pharmacy and Pharmaceutical Sciences | Rheumatology | Skin and Connective Tissue Diseases


BACKGROUND: Few population-based studies have reported the prevalence of psoriatic disease.

OBJECTIVE: We validated computerized diagnoses to estimate the prevalence of psoriasis and psoriatic arthritis.

METHOD: We identified adults with >/=1 ICD-9 diagnosis codes of 696.0 (psoriatic arthritis) or 696.1 (psoriasis) in clinical encounter data during 1996-2009 and used chart review to confirm the diagnoses in random samples of patients. We then used the best performing case-finding algorithms to estimate the point prevalence of psoriasis and psoriatic arthritis.

RESULTS: The number of persons with a diagnosis for psoriasis (ICD-9 code 696.1) was 87 827. Chart review of a random sample of 101 cases with at least one dermatologist-rendered psoriasis code revealed a positive predictive value (PPV) of 90% (95% CI, 83-95) with sensitivity of 88% (95% CI, 80-93). Psoriatic arthritis (code 696.0) was recorded for 5187 patients, with the best performing algorithm requiring >/=2 diagnoses recorded by a rheumatologist or >/=1 diagnosis recorded by a rheumatologist together with >/=1 psoriasis diagnoses recorded by a dermatologist; the PPV was 80% (95% CI, 70-88) with sensitivity 73% (95% CI, 63-82). Among KPNC adults, the point prevalence of psoriasis, with or without psoriatic arthritis, was 939 (95% CI, 765-1142) per 100 000, and the overall prevalence of psoriatic arthritis, with or without psoriasis, was 68 (95% CI, 54-84) per 100 000.

CONCLUSION: Within an integrated health care delivery system, the use of computerized diagnoses rendered by relevant disease specialists is a valid method for identifying individuals with psoriatic disease.

Copyright (c) 2013 John Wiley and Sons, Ltd.


Citation: Asgari MM, Wu JJ, Gelfand JM, Salman C, Curtis JR, Harrold LR, Herrinton LJ. Validity of diagnostic codes and prevalence of psoriasis and psoriatic arthritis in a managed care population, 1996-2009. Pharmacoepidemiol Drug Saf. 2013 Aug;22(8):842-9. doi: 10.1002/pds.3447. Link to article on publisher's site

Related Resources

Link to Article in PubMed


Computerized medical information, Epidemiology, Incidence, Prevalence, Health maintenance organizations, Pharmacoepidemiology, Psoriasis, Psoriatic arthritis

PubMed ID