National survey of heparin-induced thrombocytopenia in the haemodialysis population of the UK population

Background. Heparin-induced thrombocytopoenia (HIT) type II is an antibody-mediated, drug-induced thrombocytopenia which is associated with significant morbidity and mortality. Several case reports and small series have described the occurrence of HIT type II in the haemodialysis population and the challenges associated with it. Some of these reports raise the possibility of a recent increase in prevalence of this condition. But to date, there has never been a large study to estimate the prevalence, demography or treatment options for this syndrome in the haemodialysis population. Methods. The renal units in the UK were surveyed to establish the prevalence of HIT type II syndrome in the haemodialysis population. Demographic data for haemodialysis patients with HIT type II syndrome were gathered and current treatments assessed. Results. Fifty responses from the 81 UK renal units surveyed were received. The combined population for these units was 13 682 patients on dialysis of whom 10 564 were on maintenance haemodialysis. The prevalence and incidence of HIT type II syndrome in the UK haemodialysis population were 0.26 and 0.32 per 100 patients, respectively. The mean age of the patients with HIT type II syndrome was 62 years (range 22-86), 52% were females and 92% were Caucasians. Only 17% of patients have had complications of HIT syndrome. Thirty-six percent of renal units use danaparoid as anticoagulant of choice for patients on haemodialysis with HIT type II syndrome. Conclusion. This is the largest survey of HIT type II in the haemodialysis population to date. The prevalence is considerably lower (0.26 per 100 patients) than previous estimates, with only a minority of patients developing complications of the condition. Haemodialysis patients with HIT type II in the UK are predominately treated with danaparoid.