Statistical analysis
intraoperative nerve injury
POSTOPERATIVE HYPOPARATHYROIDISM
Statistical analyses were undertaken in accordance with the protocol. Incorrectly randomized subjects with violation of one or more entry criteria were excluded from the analysis if the criterion violated had been measured and documented before randomization. Patients who had a unilateral procedure on clinical grounds (mostly owing to suspected intraoperative nerve injury), were excluded from the analysis, because these patients by definition had no risk of postoperative hypoparathyroidism.The two-sided confirmatory null hypothesis for the primary endpoint and two-sided exploratory null hypotheses for other endpoints were analysed in between-group comparisons using Pearson’s χEstimated relative risks (RRs) are presented with 95 per cent confidence intervals, unstratified and stratified with Mantel–Haenszel weighting. Multivariable statistical models were computed using the proportional hazards model with constant follow-up and the Huber–White sandwich estimator to estimate RRs directly