Hereditary haemorrhagic telangiectasia: a population-based study of prevalence and mortality in Danish patients.

Hereditary haemorrhagic telangiectasia (HHT) is a dominantly inherited disease characterized by telangiectatic lesions. The disease manifestations are variable and include epistaxis, gastrointestinal bleeding, pulmonary arteriovenous malformations and cerebral arteriovenous malformations. Early death due to these complications has been described. We report a study on the prevalence and mortality of HHT in a Danish population based on two cross-sectional surveys in combination with a long-term follow-up study. Prevalent cases of HHT as of 1 January 1974 in the County of Fyn, Denmark, were identified. In 1995-97 a follow-up study of mortality was performed of the initial patient sample, and a new point prevalence rate of HHT as of 1 January 1995 was calculated. All live patients and their families were invited to attend a detailed clinical examination. The prevalence of HHT in the County of Fyn was 13.8 per 100,000 on 1 January 1974 and 15.6 per 100,000 on 1 January 1995. In the HHT group as a whole, we found a slightly increased mortality; however, amongst the HHT patients younger than 60 years at inclusion the mortality of HHT patients was twice the expected. The excess mortality could be fully explained by severe HHT symptoms. This study suggests that HHT is more prevalent than previously believed. In young patients the disease is associated with an excess mortality which is fully attributable to HHT. Future research should aim at the identification of HHT patients at particular risk of developing severe complications.