Observational study of diagnosis and management in adult primary hypothyroidism in southwest of Sweden

OBJECTIVE: The objective was to explore the management of newly diagnosed hypothyroidism in adults regarding laboratory diagnostics and treatment in Region Halland (RH). In addition, to investigate whether current recommendations were followed regarding diagnostics. DESIGN: Retrospective observational study. SETTING: A population-based study utilizing healthcare registry data from all public primary health care (PHC) clinics in RH during 2014-2019. SUBJECTS: Newly diagnosed patients with hypothyroidism according to ICD-10, aged ≥18 years when diagnosed and living and receiving health care in RH. There were 2494 patients included in the study. MAIN OUTCOME MEASURES: Registrations of thyroid laboratory values, diagnostic codes, and drug treatment was collected. Demographic data were also recorded. Laboratory values were checked also after 12-24 months after initial diagnosis. The main outcome was the proportion with elevated TSH and TPO and how the TSH value had changed at the follow-up. RESULTS: There were 1431 (61%) patients who had elevated TSH at the onset of the disease and TPO was tested in 1133 (46%) of the patients. Elevated TPO was found in 566 (23%) of the patients. After one year, there were 1908 (76%) patients who obtained a prescription for levothyroxine. In 1127 (45%) patients, TSH had normalized within one year. CONCLUSION: There were 39% of the patients diagnosed with hypothyroidism despite normal or subclinical TSH. There was an underuse of TPO in diagnosis and this advocated that the criteria for diagnostics according to current guidelines be followed to avoid unnecessary treatment.