Table 1.

Preoperative demographic, clinical and biochemical characteristics of patients in the study.

Factor	N=88 patients and 98 reoperations
Disease, No. (%)
pHPT	57 (64.8)
rHPT	31 (35.2)
Initial parathyroid surgery, No. (%)
At our institution, total	16 (18.2)
pHPT	6 (6.8)*
rHPT	10 (11.4)*
Outside our institution, total	72 (81.8)
pHPT	51 (60.0)*
rHPT	21 (23.8)*
Sex (F / M); No. (%)	69 (78.4)/19 (21.6)
Age, mean (range); years
Female	50.3 (24–78)
Male	40.4 (17–81)
Calcium, mean (range); mmol/l	2.71 (2.30–4.24)
Phosphate, mean (range); mmol/l	0.77 (0.40–1.38)
Kreatinine, mean (range); μmol/l	95.26 (35.36–268.74)
Alkaline phosphatase, mean (range); IU/l	120.38 (50.0–167.0)
Urea, mean (range); mmol/l	5.93 (2.99–20.92)
iPTH, mean (range); ng/l	322.75 (70.34–1137.0)
Symptomatic disease, No (%)	66 (75.0)
Renal stones	39 (44.3)
Osteoporosis	31 (35.2)
Arterial hypertension	17 (19.3)
Risk of hyperkalcemic crisis	15 (17.0)
GI symptoms	14 (15.9)
Impaired renal function	14 (15.9)
Asymptomatic disease, No. (%)	22 (25.0)
Calcium, mean (range); mmol/l	3.04 (2.62–4.24)
iPTH, mean (range); ng/l	285.06 (87.64–509.0)
Previous surgery before referral, No. (%)
1	80 (90.9)
2	8 (9.1)
Time from initial surgery to reoperation, months (range)	35.2 (0.13–192.0)
pHPT	17.5 (0.13–84.0)
rHPT	77.3 (15.0–192.0)
Solitary disease	31.0 (0.13–156.0)
MEN 1	55.0 (12.0–132.0)
MEN 2A	0.13 (0.13–0.13)
Preoperative unilateral RLN injury, No. (%)	4 (4.5)

^*p=0.011 (χ²-test); pHPT – persistent primary hyperparathyroidism; rHPT – recurrent primary hyperparathyroidism; iPTH – intact parathormone; MEN – multiple endocrine neoplasia; RLN – recurrent laryngeal nerve; reference ranges: total serum calcium (2.15–2.60 mmol/l); total serum phosphate (0.81–1.45 mmol/l); serum creatinine (60.0–130.0 μmol/l); serum alkaline phosphatase (38.0–126.0 IU/l); urea (2.5–6.7 mmol/l); iPTH (15.0–65.0 ng/ml).