Juan J. Díez ^1,2* Emma Anda ³ Begoña Pérez-Corral ⁴ Miguel Paja ⁵ Victoria Alcázar ⁶ Cecilia Sánchez-Ragnarsson ⁷ Aida Orois ⁸ Ana R. Romero-Lluch ⁹ Marcel Sambo ¹⁰ Amelia Oleaga ¹¹ Águeda Caballero ¹² María R. Alhambra ¹³ Virginia Urquijo ¹⁴ Ana M. Delgado-Lucio ¹⁵ Jose Carlos Fernández-García ¹⁶ Viyey K. Doulatram-Gamgaram ¹⁶ Suset Dueñas-Disotuar ⁹ Tomás Martín ¹⁷ Mercedes Peinado ¹⁷ Julia Sastre ¹⁸

• ¹ Puerta de Hierro University Hospital Majadahonda, Madrid, Spain
• ² Instituto de Investigación Sanitaria Puerta de Hierro - Segovia de Arana, Hospital Universitario Puerta de Hierro Majadahonda, Majadahonda, Spain
• ³ Complejo Hospitalario de Navarra, Pamplona, Navarre, Spain
• ⁴ Complejo Asistencial Universitario de León (CHLeon), Leon, Spain
• ⁵ Basurto Hospital, Bilbao, Basque Country, Spain
• ⁶ Hospital Universitario Severo Ochoa, Madrid, Madrid, Spain
• ⁷ Central University Hospital of Asturias, Oviedo, Spain
• ⁸ Hospital Clinic of Barcelona, Barcelona, Catalonia, Spain
• ⁹ Virgen del Rocío University Hospital, Seville, Spain
• ¹⁰ Gregorio Marañón Hospital, Madrid, Madrid, Spain
• ¹¹ Basurto University Hospital, Osakidetza Basque Health Service, Bilbao, Basque Country, Spain
• ¹² Canary Islands University Hospital, Santa Cruz de Tenerife, Spain
• ¹³ Reina Sofia University Hospital, Cordoba, Spain
• ¹⁴ Hospital de Cruces, Barakaldo, Spain
• ¹⁵ Burgos University Hospital, Burgos, Spain
• ¹⁶ Regional University Hospital of Malaga, Málaga, Andalusia, Spain
• ¹⁷ Virgen Macarena University Hospital, Seville, Spain
• ¹⁸ Hospital Virgen de la Salud, Toledo, Spain

Purpose. The identification of patients with chronic hypoparathyroidism who are adequately (AC) or not adequately controlled (NAC) has clinical interest, since poor disease control is related to complications and mortality. We aimed to assess the prevalence of NAC patients in a cohort of subjects with postsurgical hypoparathyroidism.Methods. We performed a multicenter, retrospective, cohort study including patients from 16 Spanish hospitals with chronic hypoparathyroidism lasting ≥3 years. We analyzed disease control including biochemical profile and clinical wellness. For biochemical assessment we considered three criteria: criterion 1, normal serum calcium, phosphorus and calcium x phosphorus product; criterion 2, the above plus estimated glomerular filtration rate ≥60 ml/min/1.73 m 2 ; and criterion 3, the above plus normal 24hour urinary calcium excretion. A patient was considered AC if he or she met the biochemical criteria and was clinically well.Results. We included 337 patients with postsurgical hypoparathyroidism (84.3% women, median age 45[36-56] years, median time of follow-up 8.9[6.0-13.0] years). The proportions of NAC patients with criteria 1, 2 and 3 were, respectively, 45.9%, 49.2% and 63.1%. Patients who had dyslipidemia at the time of diagnosis presented a significantly higher risk of NAC disease (criterion 3;]; P=0.016).NAC patients (criterion 2) had a higher proportion of subjects with incident chronic kidney disease and eye disorders, and NAC patients (criterion 3) had a higher proportion of incident chronic kidney disease, nephrolithiasis and dyslipidemia than AC patients.The present study shows a strikingly high prevalence of NAC patients in the clinical practice of Spanish endocrinologists. Results suggest that NAC disease might be associated with some prevalent and incident comorbidities.