Incidence and cause of aplastic anemia, hemolytic anemia, agranulocytosis and thrombocytopenia.

A total of 745 patients with cytopenia (aplastic anemia 157, hemolytic anemia 101, agranulocytosis 136, thrombocytopenia 351) were diagnosed during a 5-year period in a health care region comprising 16% of the Swedish population. The total incidence was for aplastic anemia 24.6, hemolytic anemia 15.8, agranulocytosis 21.3 and thrombocytopenia 55.0 cases per 10(6) and year. Compared to 10 years earlier, aplastic anemia and agranulocytosis have become more common, thrombocytopenia occurs with unchanged frequency while hemolytic anemia is rarer. The overall incidence is 5 times higher in elderly (greater than 65 y.) than in younger patients and 1.3 times higher in women than in men, figures that make total incidence figures rather meaningless. The most common cause is "unknown" (45%), the next drug-induced (25-36% including cytostatic drugs). Disregarding cytostatics, the drugs most often encountered are oral diuretics, analgesics, antiphlogistics and sulfonamides.