Validity of ankylosing spondylitis and undifferentiated spondyloarthritis diagnoses in the Swedish National Patient Register

Abstract

The diagnosis codes for AS or uSpA had high PPVs, suggesting that our case identification in the Swedish NPR can be used for nationwide, population-based, epidemiological studies of these diseases.

Societal costs and patients' experience of health inequities before and after diagnosis of psoriatic arthritis: a Danish cohort study

“…However, according to a previous study in Sweden (a Scandinavian country closely resembling Denmark), this is a minor problem and would only increase the number of cases by <4%, at the expense of a larger degree of misclassification 27. Regarding the case definitions of PsA used in this study data and results from another group, spondyloarthritis and ankylosing spondylitits, data suggest that misclassification occurs in <10% 22. Concerning comorbidities such as acute coronary events, misclassification is estimated to be <5% 19 25…”

The effect of comedication with conventional synthetic disease modifying antirheumatic drugs on TNF inhibitor drug survival in patients with ankylosing spondylitis and undifferentiated spondyloarthritis: results from a nationwide prospective study

“…Misclassification of AS and uSpA could be a problem. We have, however, recently validated and found good validity for the diagnoses of AS and SpA in large patient samples of randomly selected clinical records in the NPR 25. The patients in the present study, who were treated with TNFi, constitute subgroups with more severe disease where proportions fulfilling classification criteria would be expected to be higher 26.…”

Risk of cardiac rhythm disturbances and aortic regurgitation in different spondyloarthritis subtypes in comparison with general population: a register-based study from Sweden

“…In patients with AS and available data of imaging and/or HLA-B27 status, the positive predicted values (PPVs) for fulfilling the modified New York criteria and any set of SpA criteria were 80% and 97%, respectively 20. The corresponding PPVs in uSpA were 26% and 89%, respectively 20.…”

“…In patients with AS and available data of imaging and/or HLA-B27 status, the positive predicted values (PPVs) for fulfilling the modified New York criteria and any set of SpA criteria were 80% and 97%, respectively 20. The corresponding PPVs in uSpA were 26% and 89%, respectively 20. The PPVs of an ICD code for PsA within primary or specialised care was within the range of 63%–92%, where the highest proportion of confirmed PsA was noted if the PsA was diagnosed in specialised care (as the patients with PsA in the present study) and at least on two occasions 21…”