Biochemical Control of 78 Patients with Chronic Hypoparathyroidism Referred between 2006 and 2020 – Where do We Actually Stand?

Abstract Hypoparathyroidism (hypoPT) is a relatively rare endocrine disease, mainly due to thyroid surgery. The classical supplementation with calcium and active vitamin D may represent a challenge to the clinician. Objective To describe the level of biochemical control in patients with chronic hypoPT and to look for differences between postsurgical and non-surgical cases referred between 2006 and 2020. Materials and Methods This was a retrospective cross-sectional study with data review from the database of a tertiary endocrine clinic from the last 15 years. Cases with hypocalcemia not related to PTH were excluded. The patients’ medical history was reviewed as well as concomitant diseases and medications. Serum calcium (total, albumin-corrected and ionized; sCa, corrCa, iCa+) and phosphates (P), magnesium, creatinine, alkaline phosphatase together with 24hr urinary calcium and phosphate were measured. The intact parathyroid hormone (iPTH) was determined by electro-hemi-luminescence (Elecsys, Roche Diagnostics). Thyroid and abdominal ultrasound (US) were both performed. Results Seventy-eight patients met the study criteria – 69 were females. Most of them were between 30 and 60 years (mean age 50.6 ± 14.5 years). Albumin-corrected calcium was in target in 20.5% of the patients, ionized calcium – in 36.5%, serum phosphate – in 46.3%, serum magnesium – in 87.9%. When all four parameters were taken together, less than 20% were in target. Hypercalciuria was registered in 11.8%, while 57.1% of the patients had nephrolithiasis and 27.3% had CKD grade 3-4. Thus, a high proportion of patients with kidney involvement was identified. Calcium carbonate and calcitriol were the preferred replacement choices. Comparing patients with post-surgical and non-surgical hypoPT significant differences were found only for age, total serum calcium, serum magnesium and TSH. Conclusion Our study is the first of its kind in our country during the last two decades describing the contemporary clinical and biochemical picture of chronic hypoPT in patients referred for specialized care. Low supplementation doses leading to hypocalcemia and hyperphosphatemia were a common finding. Low patient’s adherence may be just one possible explanation. Non-surgical cases tend to have even lower calcium and magnesium levels. The patients, their families and treating physicians should be better informed about up-to-date management of chronic hypoPT and the possible impact of suboptimal treatment on morbidity and mortality of the affected subjects.