Translation and Validation of the Hypoparathyroidism Patient Experience Scales (HPES) Questionnaire in Greek

This is a crossectional study that will be conducted at several tertiary centers in Greece.

To participate in the study, patients should be ≥18 years of age, fluent in Greek language, diagnosed with chronic HP, on optimal treatment with calcium and active vitamin D metabolites. Chronic HP is defined when continuous therapy with calcium and vitamin D is required for \>12 months.

Exclusion criteria will include:

1. Patients inadequately controlled with conventional therapy:

1. corrected serum Ca (cCa) ≤8 mg/dl or cCa ≤8.2 mg/dl with symptoms of hypocalcemia 2. serum P \>5.5 mg/dl 2. Age \>80 years 3. Presence of neoplastic disease 4. Pregnancy 5. Diagnosis of psychiatric disease or cognitive impairment 6. Participants experiencing other comorbidities that may affect QoL 7. Lack of informed consent The study will seek approval from the Ethics in Research Committee of its participating center. All participants will be informed about the objectives of the study and will sign an informed consent.

The HPES-Symptom was developed in accordance with the Food and Drug Administration guidance and best research practices for PRO measure development. The methodology used has been previously described.

The first step of the translation process requires two forward translations of the English version of the questionnaire. The translations will be done by two translators who are native speakers of the target (Greek) language and can understand the English version. Then a reconciled translation is made based on the two translations - that is, the chief investigator will review the two translations to achieve the best possible version by choosing one of the two translations or by combining them on the basis of their correctness, wording etc.

The next step requires translating the reconciled version back into English, again done by two translators who will be native speakers of English or at least will have a very good command of English.