Essential thrombocythemia is a chronic disease common in people over age 50 and slightly more common in women. Young people can develop it as well. It is characterised by the overproduction of platelets by megakaryocytes in the bone marrow. Essential thrombocythemia is an uncommon disorder where the body produces too many blood platelets. This condition may cause to feel fatigued, lightheaded and to experience headaches and vision changes. It also increases the risk of blood clots.
The greatest health risk in patients with ET is an increased risk of developing blood clots. Blood clots can be in the deep vessels of the legs or lungs; ET patients are also more likely to experience strokes and heart attacks. ET patients can develop clots elsewhere, including within the abdomen, an otherwise rare site for clots to form. The risk of clotting increases with age, and disease-associated risks may be quite different for children than for adults, with children generally being at low risk for clots and other problems related to ET.
Patient survival was considerably lower in all MPN subtypes compared with expected survival in the general population, reflected in 10-year RSRs of 0.64 (95% CI, 0.62 to 0.67) in patients with PV, 0.68 (95% CI, 0.64 to 0.71) in those with ET, and 0.21 (95% CI, 0.18 to 0.25) in those with PMF. Excess mortality was observed in patients with any MPN subtype during all four calendar periods (P < .001). Survival improved significantly over time (P < .001); however, the improvement was less pronounced after the year 2000 and was confined to patients with PV and ET.