Endocrine Abstracts

Background: In some patients with primary hyperparathyroidism (PHPT), glomerular filtration rate (GFR) demonstrate decrease after parathyroidectomy (PTE). GFR may decrease immediately after surgery due to general anesthesia, but after a month not all patients restore kidney function; a decreased GFR is also observed after 1–2 years after surgery.

Aim: To find the pre-surgical factors of GFR decrease after PTE.

Methods: Patients with PHPT who underwent selective PTE in 1993–2010 (50% of the patients) or 2017–2020 at the Endocrinology Research Center were included. Twenty-two variables were analysed. PTH, calcium total, phosphorus were measured prior to surgery (5 days – 4 years before surgery) and administration of drugs affecting calcium-phosphorus metabolism – cinacalcet, denosumab or bisphosphonates (either as monotherapy or as a part of combination therapy). 25(OH)D, alkaline phosphatase (AP), osteocalcin, c-terminal telopeptide of type 1 collagen (CTX-1), GFR, urea, triglycerides, uric acid, dual-energy X-ray absorptiometry and clinical characteristics were measured on 4–365 days before surgery. GFR was also estimated at 12 months after surgery.

Results: 206 patients were included, aged 57 [47; 62] years, 19 (9%) male and 187 (91%) female. On 12 months after surgery 56 of them (27%) progressed to more severe stage of CKD (group 1), and 150 remained at the same stage of CKD (group 2): in the group 1 there were 25 (45%) patients with CKD C2, 17 (30%) with CKD C3a, 8 (14%) with CKD C3b, 6 (11%) with CKD C4, in the group 2 there were 65 (43%) patients without CKD, 63 (42%) with CKD C2, 13 (9%) with CKD C3a, 7 (5%) with CKD C3b, and 2 (1%) with CKD C5. There were no differences in sex, age, BMI, frequency of renal colic and stones, initial stages of CKD, initial GFR, frequency of bone fractures and osteoporosis between the groups. There were also no differences in phosphorus–calcium metabolism (total calcium, ionized calcium, and phosphorus), lipid metabolism (total cholesterol, LDL and HDL cholesterol, triglycerides), PTH, uric acid, urea, osteocalcin and CTX-1. AP was higher in group 1 (309.0 vs 190.3 IU/l, P<0.001, U-test).

Conclusions: Groups with decreased and stable GFR significantly differ by bone remodeling marker AP, but not in clinical manifestations of bone disorder. Moreover, groups were comparable in terms of GFR, uric acid and renal complications (renal colic and stones, CKD).