Clinical characteristics and depression score response after parathyroidectomy in primary hyperparathyroidism

Objective Several studies indicate that patients with primary hyperparathyroidism (PHPT) undergoing parathyroid surgery have improvement in mood and neuropsychological functioning. The current analysis aims to examine the relationship between biochemical and clinical variables and the improvement in depression scores and in specific symptoms, after parathyroidectomy. Design A prospective observational case-control study at a referral centre. Patients Patients with PHPT undergoing parathyroidectomy (n = 88) or thyroid surgery (n = 85). Measurements The Patient Health Questionnaire-9 (PHQ-9) was utilized to obtain depression scores at enrolment and 12 months after surgery. The changes in PHQ-9 were analysed and correlated with baseline clinical and biochemical parameters. Results At enrolment, there was no difference between the groups in the number with a depression diagnosis (PHPT 34.1%, thyroid surgery, 35.5%, P = 0.86). However, baseline PHQ-9 scores were significantly higher in PHPT (median 7.5, range 0-27) than thyroid surgery patients (median 3.0, range 0-18, P < 0.0001). Following surgery, all PHQ-9 scores, total and symptom group (cognitive, somatic) improved and were no longer different between PHPT (total PHQ-9 median 2, range 0-16) and thyroid (median 1, range 0-14, P = 0.31) groups. Baseline parathyroid hormone level, but not calcium, had a weak relationship with change in PHQ-9 score after parathyroid surgery (P = 0.003). Baseline PHQ-9 score was correlated with change in PHQ-9 score at 12 months after parathyroid surgery (P < 0.001). Conclusions Depression scores improve in both somatic and cognitive domains after parathyroidectomy for PHPT and baseline severity of depression predicts the response.