Prevalence of Thrombophilia In Patients with Sickle Cell Disease and Osteonecrosis

Osteonecrosis (ON) of the femoral and humeral heads is frequently seen in patients with sickle cell disease (SCD). Earlier studies reported a high prevalence of thrombophilia in patients with ON.

To study the prevalence of thrombophilia in patients of SCD with ON.

Case records of SCD patients with ON were retrospectively reviewed for protein S, protein C, and anti-thrombin deficiency, along with activated protein C resistance (APCR).

A total of sixty-three patients were identified, 35 of whom were males, with a median age of 21 years (range 15to 46). Median haemoglobin, total white cell count and platelet counts were 10 g/dL (range 7.7to 13.3), 7.5 ×10⁹/L (range 3.4 to 16.7) and 302 ×10⁹/L (range 72 to 1101) respectively. Twenty-eight patients were on hydroxyurea. Thrombophilia testing showed that 29% (95% confidence interval: 17–40), 47% (95% CI: 29–64) and 79% (95% CI: 65–93) of the patients had low levels of functional (<60 unit/dl), total antigenic (<70 unit/dl) and free antigenic (<70 unit/dl) protein S respectively, while 21% (95% CI: 10–31) and 67% (95% CI: 46–87) had low levels of functional (<70 unit/dl) and antigenic (<70 unit/dl) protein C respectively. In addition, 14% (95% CI: 5–23) and 22% (95% CI: 0–56) of the patients had low levels of functional (<80 unit/dl) and antigenic (<80 unit/dl) anti-thrombin levels respectively. Only 2% (95% CI: 0–5) of these patients had an abnormally low APCR (APCR ratio ≤2.3).

Patients with SCD and ON have a high prevalence of thrombophilia. These results indicate that a prospective study with more detailed thrombophilia work-up, along with confirmatory DNA analysis, as well as a study of the role of prophylactic anticoagulation in such patients is highly warranted.

Pathare:Sultan Qaboos University: Employment, Research Funding. Alkindi:Sultan Qaboos University: Employment, Research Funding.