Splenectomy and the Incidence of Venous Thromboembolism and Sepsis In Patients with Immune Thrombocytopenia,

Splenectomy is efficacious for many patients with chronic immune thrombocytopenia (ITP) refractory to initial corticosteroid therapy. However, there are concerns about short and long term complications, especially venous thromboembolism (VTE) and sepsis. Information regarding the incidence and risk factors for these complications might inform therapeutic decisions.

Using the California Office of Statewide Health Planning and Development Patient Discharge Dataset, we identified all the records of Californians discharged with a diagnosis of ITP from 1991–2009. Similarly, all records with a procedure code for splenectomy, or principal or secondary diagnosis of VTE or sepsis were identified. The resultant datasets were then merged with the ITP dataset so that incident splenectomy, VTE, and sepsis could be determined for the ITP cohort.

A total of 37,780 unique patients were initially identified with an ITP code, of which 13,798 were in the principal position. Records where the first ITP code was on the same date as a splenectomy were then excluded as we wished to study a cohort of ITP cases that warranted admission but may or may not have undergone splenectomy later. This resulted in 10,752 cases that constitute the ITP analysis cohort. This cohort was 60% female, 57% White, 23% Hispanic, 9% Asian, and 8% African-American with a median age of 54 years. One thousand nine hundred fifty-five ITP patients underwent splenectomy subsequent to their first ITP hospitalization; 8,797 did not. The cumulative incidences of VTE were 4.4% and 1.8%, and for sepsis were 7.9% and 6.7%, for patients who did and did not undergo splenectomy, respectively. Cox proportional hazard models for VTE and sepsis are given in the tables.

In this large cohort of cases with ITP, splenectomy was associated with hazard ratios (HR) of 2.6 to 4.8 for VTE and a HR of 8.2 in older patients for sepsis, confirming the results of smaller studies. Age and diagnosis of lupus also increased the risk of VTE. Asians had a lower risk of VTE, consistent with previous findings. The absolute risk of VTE was < 5% and would not seem to warrant long-term primary prophylaxis. Age, lupus, and co-morbidities also increased the risk of sepsis in patients with ITP. The increased risk of sepsis in Asians is unexplained. Of note, the cumulative incidence of sepsis in patients that did not undergo splenectomy was still considerable and may have reflected the use of immunosuppressive therapy.

Wun:Glycomimetics, Inc.: Research Funding; Eli Lilly, Inc.: Research Funding.