Mid-Term and Long-Term Impact of Permanent Hypoparathyroidism After Total Thyroidectomy

Background Permanent hypoparathyroidism (PH) is the most frequent long-term complication after total thyroidectomy. PH is related to many short-term and long-term complications, including clinical manifestations of hypocalcemia, hypercalcemia due to overtreatment, hyperphosphatemia, gastrointestinal, neuropsychiatric symptoms, decrease in renal function and infectious complications. The aim of this study was to identify the most frequent effects of PH and its associated risk factors. Methods We performed a retrospective analysis of a single institutional series of patients who developed PH after total thyroidectomy between 2000 and 2016. PH was defined as hypoparathormonemia (≤12 pg/mL) or the need for calcium/vitamin D supplementation to achieve normal calcium levels for more than 12 months. Descriptive and inferential statistics were employed based on the natural scaling of each included variable. Results Thirty-nine patients fulfilled the criteria for PH. Mean ± SD age was 46.26 ± 13.4 years; 6 (15.4%) were males and 33 (84.6%) females. Mean follow-up was 6.13 ± 3.25 years. Mean calcium carbonate supplementation doses per day were 18.95 ± 17.5 g and 21.4 ± 19.3 g at 1 year and last follow-up, respectively. Hypocalcemic crisis was the most common complication (66.7%), followed by neuropsychiatric (38.5%) and gastrointestinal symptoms (33.3%). Ten patients showed a decrease in renal function (eGFR drop ≥25%) and 4 developed chronic kidney disease. The amount of calcium supplementation was the most relevant related risk factor. Conclusions PH is associated with multiple complications, including renal function impairment, gastrointestinal, neuropsychiatric and infectious complications. Lower calcium supplementation doses are related to lower complications rates.