INTRODUCTION: Tonsillectomy is one of the most common procedures in the field of ear, nose and throat procedures. In 2012, the annual incidence in Denmark was 129.4 per 100,000 inhabitants. A common complication is post-tonsillectomy haemorrhaging (PTH). The overall PTH rates vary widely among studies ranging from 0.5% to 33%.

METHODS: This was a nationwide open-population, retrospective and registry-based cohort study in Danes who underwent tonsillectomy complicated by PTH in hospitals and private otorhinolaryngology (ORL) offices in the period from 1991 to 2012.

RESULTS: In the 1991-2012 period, a total of 177,211 tonsillectomies were performed among which 9,221 had a registered PTH (rPTH) (5.2%). The annual incidence rate of rPTH increased from 3% in 1991 to 13% in 2012 (p less-than 0.05). Males aged 20-40 years had a significantly higher risk of rPTH with the highest increase in rPTH incidence rates from 9.0% in 1998 to 16.4% in 2012 (p less-than 0.05). Approx. 12% had a primary rPTH within the first 24 hours; the maximum incidence of rPTH was on day six (14%).

CONCLUSIONS: The rate of rPTH increased from 1991 to 2012 in hospitals and in private ORL office settings alike. There was a significantly higher rate of rPTH in the age group of 20-40 years and a significant geographical difference in rPTH. The highest risk of rPTH was observed on the day of surgery and on day six.

TRIAL REGISTRATION: The Danish Data Protection Agency (record number 2012-41-0158) approved this study.

FUNDING: The Olga Bryde Nielsen Foundation and H. Skouby & E. Skouby's Foundation supported this study financially.