Conclusion
The validity of the ICD-10 diagnosis of hypoparathyroidism in the Swedish National Patient Register is high and the register is a reliable source for further research. There is a risk of miscoding when assigning an ICD-code to the medical records. We urge clinicians to be aware of this risk, especially the risk of mix-ups with the more common diagnosis of hyperparathyroidism.
Methods
We included patients with the ICD-10 diagnosis of hypoparathyroidism that were found in the Swedish National Patient Register during 2004 to 2016. Through the unique national registration number assigned to all Swedish inhabitants, we could link this information to the Swedish Prescribed Drug Register. We included patients with an ICD-10 diagnosis for hypoparathyroidism and on concurrent conventional treatment for the disease. The validation of the diagnosis was assessed through review of medical records of 120 patients.
Results
A total of 958 patients, 70% women (n=671) and 30% men (n=287) met the inclusion criteria. In total, 120 randomly chosen medical records were reviewed and 109 cases were confirmed. This corresponds to an overall positive predictive value of 91%.