Evaluating risk factors for re-exploration due to postoperative neck hematoma after thyroid surgery: a nested case-control study

Purpose Postoperative bleeding after thyroid surgery remains a potentially lethal complication. Outpatient thyroidectomy is an increasing trend in the high volume centers. There is a need to identify risk factors for postoperative bleeding in order to select proper patients for outpatient thyroidectomy. This study aimed to investigate this issue using a national population-based register. Material and method A nested case-control study on patients registered in the Swedish national register for endocrine surgery (SQRTPA) was performed. Patients with postoperative bleeding were matched 1:1 by age and gender to controls. Additional information on cases and controls was obtained from attending surgeons using a questionnaire. Risk factors for postoperative bleeding were evaluated with logistic regression and are presented as odds ratios (ORs) with 95% confidence intervals (CIs). The time of bleeding in relation to surgery was also investigated. Results There were 9494 operations, and 174 (1.8%) of them involved postoperative bleeding. In the whole cohort, patients with postoperative bleeding were older, 58 (46–69) vs. 49 (37–62) years, than patients without, p