Drug prescription pattern in patients with chronic hypoparathyroidism in Sweden

Hypoparathyroidism (HypoPT) is a rare endocrine disorder. Epidemiological studies on HypoPT are few and mostly cover certain subgroups of the disease. The most common cause of HypoPT is inadvertent removal during thyroid surgery or parathyroid gland injury. The overall aim of this study was to increase the knowledge about the etiology, epidemiology, and comorbidity of HypoPT in Sweden. The objective was to describe the drug prescription pattern in patients with chronic HypoPT after diagnosis compared with population controls in Sweden. Through the Swedish National Patient Register and the Swedish Prescribed Drug Register, patients with both a diagnosis of HypoPT were identified and at least one dispensation of active vitamin D 6 months prior through 12 months after inclusion during the period 2005- 2016. To make sure only to include patients with chronic HypoPT in the study they had to have at least 2 dispensations of active vitamin D 13-24 months after first registered with a HypoPT diagnosis in the patient registry. A total of 1210 patients fulfilled these strict criteria. For each patient, ten controls, matched by age, gender, and county of residency, were identified by the Swedish Total Population Register. By using the Swedish Prescribed Drug Register the drug prescription pattern after the diagnosis was determined by calculating the rate ratio and the odds ratio for each drug. In this study, with these strict inclusion criteria, the prevalence of chronic HypoPT was 123 per million in Sweden which is similar to Norway. The results indicate that HypoPT patients used more drugs to treat the cardiovascular system, infections, epileptics, anxiety, and depression compared with controls. Interestingly, HypoPT patients had more dispensations of drugs for the respiratory system, and for gastro-oesophageal reflux disease compared with controls. Reflecting higher comorbidity in patients with HypoPT. Those results are important to improve treatment, follow-up, and long-term outcomes of the disease