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Published on: February 8, 2019
Positive Predictive Value of the Giant Cell Arteritis Diagnosis in the Danish National Patient Registry: A Validation
Peter Engholm Hjort1,2, Philip Therkildsen1,2, Berit Dalsgaard Nielsen1,2,3
1Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark.
Insights
The Danish National Patient Registry (DNPR) shows a 62% positive predictive value (PPV) for giant cell arteritis (GCA) diagnoses. Increased PPV for GCA is seen with more glucocorticoid prescriptions and hospital contacts, but this excludes some patients.
Area of Science:
- Rheumatology
- Epidemiology
- Health Informatics
Background:
- Giant cell arteritis (GCA) is a serious condition requiring accurate diagnosis.
- The Danish National Patient Registry (DNPR) is a valuable resource for epidemiological research.
- Validating diagnostic codes in national registries is crucial for reliable health data.
Purpose of the Study:
- To determine the positive predictive value (PPV) of the giant cell arteritis (GCA) diagnosis within the Danish National Patient Registry (DNPR).
- To assess the impact of specific clinical indicators on the PPV of GCA diagnoses in the DNPR.
Main Methods:
- A cohort of 293 patients aged 50 years and older with a first-time GCA diagnosis in the DNPR (2012-2017) was retrospectively reviewed.
- Two independent investigators validated GCA diagnoses by examining medical records, treatment, laboratory results, histopathology, and imaging.
- Sub-analyses explored PPV based on glucocorticoid prescription numbers, temporal artery biopsies, and GCA-related hospital contacts.
Main Results:
- The overall PPV for GCA in the DNPR was 62% (183/293 confirmed cases).
- PPV increased to 78% (166/214) with at least three redeemed glucocorticoid prescriptions.
- PPV further increased to 93% (88/95) with at least three glucocorticoid prescriptions and three GCA-related hospital contacts, though this subgroup represented only 88/183 confirmed GCA patients.
Conclusions:
- This study provides the first validation of the GCA diagnostic code in the DNPR.
- The overall PPV of 62% indicates a need for caution when using DNPR GCA diagnoses alone.
- While specific criteria like glucocorticoid use and hospital contacts enhance PPV, they may exclude a substantial proportion of actual GCA cases.
Purpose:
To investigate the positive predictive value (PPV) of the giant cell arteritis (GCA) diagnosis in the Danish National Patient Registry (DNPR).
Patients And Methods:
A total of 293 patients aged ≥50 years with a first-time diagnosis of GCA in the DNPR between January 2012 and December 2017 were included. Patients were sampled from two secondary and one tertiary care hospitals in the Central Region Denmark. Two independent investigators (PH & PT) reviewed all medical files, including medical records, treatment, biochemistry, histopathology and imaging, and either confirmed or dismissed the diagnosis of GCA. In case of disagreement, a consensus agreement was reached. Sub-analyses including number of redeemed prescriptions performed temporal artery biopsies (TABs), and number of GCA-related hospital contacts were performed.
Results:
We confirmed the diagnosis of GCA in 183/293 patients resulting in a PPV of 62% (95% CI: 57-68). In patients with ≥3 redeemed prescriptions of glucocorticoids (GCs), we confirmed the diagnosis in 166/214 resulting in a PPV of 78% (95% CI: 71-83). In patients with ≥3 redeemed prescriptions of GCs and ≥3 GCA-related hospital contacts, we confirmed the diagnosis in 88/95 resulting in a PPV of 93% (95% CI: 85-96); however, this only included 88/183 confirmed GCA patients.
Conclusion:
This is the first study to validate the diagnostic code of GCA in the DNPR. The overall PPV of GCA in the DNPR was 62%. Requiring redeemed prescriptions of GCs and/or GCA-related hospital contacts increase the PPV, but also excludes a significant number of GCA patients.
