Is There an Association Between Heparin-Induced Thrombocytopenia (HIT) and Autoimmune Disease?

BACKGROUND

Heparin-induced thrombocytopenia (HIT) is a drug-induced, immunoglobulin G medicated autoimmune disorder associated with several negative clinical outcomes including increased morbidity, mortality, and increased medical costs. Previous studies have shown associations between comorbid autoimmune diseases, but there is little known about associations between HIT and autoimmunity.

PURPOSE: To provide clinical data to suggest an association between HIT and autoimmunity.

METHODS

Retrospective chart review of 59 cases with a diagnosis of HIT and 251 matched controls without a HIT diagnosis, comparing the prevalence of autoimmunity in each group.

SETTING

A single, large upper Midwest health care system.

RESULTS

Patients with a diagnosis of HIT were significantly more likely to have a comorbid autoimmune disease than those without a HIT diagnosis (55.9% vs 10.8%, P < 0.001). In disease-specific analyses, patients with a diagnosis of HIT were significantly more likely to have a diagnosis of antiphospholipid syndrome (15.3% vs 0.0%, P < 0.001), systemic lupus erythematous (8.5% vs 0.4%, P = 0.001), rheumatoid arthritis (5.1% vs 0.0%, P = 0.007), Hashimoto's thyroiditis (13.6% vs 3.6%, P = 0.006), or nonischemic cardiomyopathy (5.1% vs 0.0%, P = 0.007). Patients diagnosed with HIT were significantly older than controls (P < 0.001).

CONCLUSION

This novel study gives evidence to suggest an association between HIT and autoimmune disease and suggests a need for more research into the relationship between HIT and autoimmunity. These results could alter the anticoagulation management of venous thromboembolism and acute coronary syndrome in patients with a previously identified autoimmune disease.