Guidelines for the diagnosis, investigation and management of polycythaemia/erythrocytosis

Traditionally, polycythaemia has been used to identify a group of varied disorders with an increase in circulating red cells that are typified by a persistently raised haematocrit (Hct). Since only the red cell lineage is involved, the term erythrocytosis has more validity and will be used throughout this article. Polycythaemia will be retained in relation to the clonal disorder, polycythaemia vera (PV), in which three cell lineages are involved. The purpose of this guideline is to provide a rational approach to the diagnosis, investigation and management of patients with an erythrocytosis. This will include recommendations on the management of PV, apparent and relative erythrocytosis, idiopathic erythrocytosis and the secondary erythrocytoses because of high oxygen affinity haemoglobin, hypoxia because of chronic lung disease, congenital cyanotic heart disease and postrenal transplantion. The guideline group was selected to include UK-based medical experts. The drafting group met (real or virtual) on four occasions and communicated by e-mail. Each member of the group was allocated responsibility for the preparation of a selected component of the first draft. Medline, CANCERLIT and EMBASE were systematically searched for publications in English from 1966 to June 2004. Relevant literature in group members own collections and older references generated from initial papers were also examined. The Cochrane controlled trials register and the Cochrane optimal search strategy for randomised controlled trials was searched but no additional material was identified. Randomised trials and series of patients and single case reports were considered if appropriate. Meeting abstracts were not included in the systematic search strategy. The group leader synthesised the draft components, which were subsequently revised by consensus. No recommendations are included for which full consensus was not achieved. The guideline was reviewed by sounding boards, and British Committee for Standards in Haematology (BSCH) and comments were incorporated where appropriate. Criteria used to quote levels and grades of evidence are outlined in Table I. Patients with a persistently raised venous haematocrit (Hct) (>0·52 males, >0·48 females for >2 months) should, in general, be investigated by measurement of their red cell mass (RCM). A number of physiological factors have been shown to influence the Hct value, although in practice the use of only minimal or no venous occlusion when taking the blood sample is the most important. In addition, Coulter ‘S’ and Coulter ‘S Plus’ analysers are known to underestimate Hct approximately 7% at reduced mean cell haemoglobin (MCH) values. As a result, a correction factor should be applied (Guthrie Tatarsky & Sharon, 1997), up to 15% (Najean & Rain, 1997a) at years. leukaemia is of the of PV, in patients and in those with venesection only (Berk et al, 1986). PV a as shown by an & where the median in patients was with the cause of The of of PV are therefore the of and the of transformation to acute leukaemia and which may occur including haemorrhage and and These were used when the evidence and management There have been randomised clinical trials of for PV (Table Most trials have used the for the diagnosis of PV as the that the are of the trials are without Most of these in studies of any disease with a patient and significant It also difficult to patients on allocated when information No an of the They have also been reported in ways. The of incidence of leukaemia is particularly as in some cases the incidence of acute leukaemia of a group of patients on a is reported and in the on an to is These are not However, there are about the and of various that can be from of the clinical The venesection as the first for PV. In with and was significantly in the venesection and associated with of leukaemia and An increased of was seen in the venesection but this was the first when the Hct was (Berk et al, 1995). In it was reduced to There was a large degree of between with of patients randomised to venesection having to by in the of patients in the (Najean et al, the of using venesection as for PV is was a that compared with venesection high of and et al, 1986). The for this was to use to the increased of that was initially in the of The haemorrhage and was significantly increased in the venesection and and the was therefore In the majority of cases a high count was found at the time of haemorrhage but the count was controlled by in the other The European Organisation for on of a to was in to the Hct between and was significantly in the with the major for the an increase in vascular There were no between the for other such as myelofibrosis or The Polycythaemia Study Group randomised trials in The first was a of alone with known as in patients over the age of (Najean & Rain, of patients between the was not significantly No were for vascular or progression to The of leukaemia was significantly greater for the and with the apparent after 5 and the to up to the In addition, the of was also greater for the and with a The from the was a of with in patients the age of (Najean & Rain, was in the at compared with an for the and There were no between the in vascular or rates of leukaemia or was significantly increased in the and to occur The (Najean et al, also very in their patients They patients in on 60 in and in on in and in with the patients randomised to were with or The are small that any of is of very However, the patients in the myelofibrosis but very Therefore, to is not The of myelofibrosis was higher if by The European on in Polycythemia vera the of in PV et al, and an (Gruppo Italiano Studio Policitemia, 1997). Patients were randomised between and significantly reduced the of the of thromboembolic or from The of major or minor was also significantly There was no significant increase in The results of this the about the and of that were raised by the et al, and evidence for the use of in the management of PV. secondary to the raised Hct is a cause of in PV. There is a and between the Hct and rates of (Pearson & 1978). However, platelets may also be of the evidence for the of the count is by studies in essential where the count significantly reduced the incidence of vascular events et al, 1995). In the there was no between a raised count and events (Berk et al, 1986). However, reduced the incidence of in PV et al, a for platelets in thromboembolic events. vary in the of myelofibrotic although one randomised a greater incidence for compared with (Najean & Rain, In this of the count was associated with progression to This that the count will thromboembolic events and influence the of transformation to An Hct has been associated with increased and in patients & and therefore the Hct should be controlled for can be used to the Hct in PV. In a patients with PV who were with venesection and the incidence of arterial and venous thromboembolic events increased as the Hct increased. The cerebral blood was significantly below normal in PV patients with a raised Hct and by when the Hct was than et al, that the Hct is reduced to below by There is currently no evidence to a level of Hct in males and females. has been used to the RCM et al, 1997). be used it would have significant but it be used in the very patient with an the Hct should be maintained at than by The volume should be with the patient's and B level The was included in the randomised (Berk et al, as listed in Table It was associated with a higher of acute The of acute leukaemia was higher with higher of is not now recommended in the of PV. The was used in the randomised and found to be to (see Table although both a low incidence of acute leukaemia at a median of 8 years. A single (Messinezy et al, patients with venesection and low The median was years. leukaemia and myelofibrosis were significantly increased above the normal but there were some with These studies that low is in PV since is an it should be reserved for the elderly. is a of to which and and of It has been used in but not in the It has been used in a number of series of patients and one randomised (Najean & Rain, of acute leukaemia from to have been in one series where a of was et al, and in which some patients were also with other of myelofibrosis from to have been by a by the which has a in the of It has been used in a and a number of case The was a that included and patients et al, was in the patients and in the This showed that was but recommended reduction because of The patients in this were compared with randomised to venesection in et al, with the Hct maintained at than There was including the after the of and no in the of With prolonged there was no in the incidence of myelofibrosis between the et al, 1997). Therefore, is using the There has been on the of In a series of reports on the use