Essential thrombocythaemia

How common are myeloproliferative neoplasms? A systematic review and meta-analysis

Myeloproliferative neoplasms (MPNs) are a heterogeneous group of diseases including polycythemia vera (PV), essential thrombocythemia (ET), and primary(idiopathic) myelofibrosis (PMF). In this systematic review, we provide a comprehensive report on the incidence and prevalence of MPNs across the globe. Electronic databases (PubMed, EMBASE, MEDLINE, and Web of Science) were searched from their inception to August 2012 for articles reporting MPN incidence or prevalence rates. A random effects meta-analysis was undertaken to produce combined incidence rates for PV, ET, and PMF. Both heterogeneity and small study bias were assessed. Thirty-four studies were included. Reported annual incidence rates ranged from 0.01 to 2.61, 0.21 to 2.27, and 0.22 to 0.99 per 100,000 for PV, ET, and PMF, respectively. The combined annual incidence rates for PV, ET, and PMF were 0.84, 1.03, and 0.47 per 100,000. There was high heterogeneity across disease entities (I(2) 97.1-99.8%) and evidence of publication bias for ET and PMF (Egger test, P = 50.007 and P ≤ 0.001, respectively).The pooled incidence reflects the rarity of MPNs. The calculated pooled incidence rates do not reflect MPN incidence across the globe due to the high unexplained heterogeneity. Improved, widespread registration of MPNs would provide better information for global comparison of the incidence and prevalence of MPNs.

Interferon therapy in primary care

Interferons are proteins produced by human blood cells in response to stimulation (viral infection). The natural roles of interferons are host defense and modulation of the immune system. Therapeutic uses are based on these roles. Interferon-alpha has been widely used for malignancies, skin conditions, viral infections, and myeloproliferative disorders. Interferon-beta is a standard treatment for relapsing multiple sclerosis. Interferon-gamma therapy is currently used for chronic granulomatous disease and skin lesions (human papilloma virus related and keloids), but further research is ongoing. Side effects of interferon therapy are common and limit utility. Flulike symptoms are reported by more than 75% and depression by 10-40% of interferon users. Severe adverse effects are less common but may be life threatening, including autoimmune diseases, thrombotic-thrombocytopenic purpura, and acute renal failure. Limited use of interferon therapy during pregnancy has been described, with successful maternal and neonatal outcomes. Use of interferon therapy during early pregnancy is not an indication for termination.