|
The frequency of bleeding complications in patients with haematological malignancy following the introduction of a stringent prophylactic platelet transfusion policy |
Callow C R, Swindell R, Randall W, Chopra R |
|
|
Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology Indications for platelet transfusion among patients with haematological malignancies were examined. These were:
a platelet count of less than 10 x 10^9/L for stable patients;
a platelet count of less than 20 x 10^9/L for patients presenting with major bleeding or additional risk factors (pyrexia greater than 38 degrees C, coagulation disorder, or bone marrow biopsy);
a platelet count of greater than 20 - 50 x 10^9/L in the present and until the control of major bleeding, soft tissue bleeding requiring red blood cells (RBCs), fresh retinal haemorrhage with impaired vision, disseminated intravascular coagulation, or haemorrhagic cystitis; and
a platelet count of less than 50 x 10^9/L for patients undergoing invasive procedures.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised patients receiving intensive chemotherapy for haematological malignancies. The patients were not allowed to use aspirin or other non-steroidal anti-inflammatory drugs.
Setting The setting was a hospital. The economic study was conducted at the Department of Haematological Oncology, Christie Hospital NHS Trust, Manchester, UK.
Dates to which data relate The effectiveness and resource use data were collected during February to October 2000 and from November 2000 to January 2001. No price year was reported, but it is likely to have been 2000.
Source of effectiveness data The effectiveness evidence was derived from a single study.
Link between effectiveness and cost data The costing was assessed prospectively with the resource use collected for both groups of patients.
Study sample Power calculations to determine the sample size were not performed. All patients with haematological malignancy, who were admitted to the study hospital during November 2000 to January 2001 for the administration of cytotoxic therapy, were recruited for the intervention group in the study. The number of patients included for the control group, which was subjected to the old protocol, was not reported. A total of 2,147 study days was reported for the intervention group. This was used as the denominator of the ratio used to evaluate the comparison of bleeding episodes. A sample of 98 patients, corresponding to 2,147 patient days, was enrolled and no patient was excluded from the initial sample. The median age of these patients was 52 years (range: 16.6 - 78.2) and 36 were women. The patients where then divided into three study groups, depending on the platelet count (<10 x 10^9/L; >10 x 10^9/L and <20 x 10^9/L; and >20 x 10^9/L).
Study design This was a prospective case-control study that was conducted in a single centre, the Christie Hospital NHS Trust in Manchester (UK). No blinded assessment was performed. The assessment was conducted using anticoagulated blood samples, obtained at 06.00 hours each morning using automated analysis. Neither the length nor loss to follow-up were reported.
Analysis of effectiveness All patients included in the analysis were accounted for in the effectiveness analysis. The health outcomes estimated in the analysis were: the mean duration of neutropenia (white blood cell count <0.5 x 10^9/L) and thrombocytopenia (<20 x 10^9/L);
transplants;
minor bleeding episodes (mucocutaneous haemorrhages or haematomas not requiring RBC transfusion, retinal haemorrhage without impaired vision);
major bleeding episodes (melaena, haematemesis, petechiae, haematuria, haemoptysis, epistaxis, intercranial haemorrhage, retinal haemorrhage with impaired vision, soft tissue bleeding requiring red cell support); and
the number of patients who died during the study.
The comparability of the study groups was not reported.
Effectiveness results The mean duration of both neutropenia and thrombocytopenia was 6 days (range for neutropenia: 1 - 38; range for thrombocytopenia: 1 - 44).
There were 27 transplants from November 2000 to January 2001, and 73 from January to October 2000.
A total of 271 bleeding episodes occurred in the whole sample, of which 217 were observed in patients with platelet counts greater than or equal to 10 x 10^9/L.
There were 198 major bleeding episodes. Thirteen patients had major bleeding episodes on 1.39% (30 out of 2,147) of the study days when the platelet count was less than 10 x 10^9/L. Twenty-seven patients had major bleeding episodes on 2.32% (50 out of 2,147) of the study days when the platelet count was 10 - 20 x 10^9/L. There were 117 major bleeding episodes in 28 patients, observed on 5.45 of the study days, in patients whose platelet counts were greater than 20 x 10^9/L.
Major bleeding episodes occurred in 0.51% of the study days (11 out of 2,147) in the absence of any additional risk factors in patients with platelet counts greater than or equal to 10 x 10^9/L.
Four patients in the sample died.
Clinical conclusions The effectiveness analysis showed that a threshold of less than 10 x 10^9/L for platelet transfusion was safe in patients undergoing intensive chemotherapy, who were not actively bleeding or septic with acceptable relative risk of bleeding.
Measure of benefits used in the economic analysis The health outcomes were left disaggregated and no summary benefit measure was used. A cost-consequences analysis was therefore conducted.
Direct costs Discounting was not applied as all the costs were incurred during one year. The unit costs were not reported, but the quantities of resources were given. The health services included in the analysis were the costs of platelet units transfused, RBC, cytomegalovirus-testing supplement, and human leucocyte antigen-testing supplement. The cost of platelets units transfused was related to patient activity, as measured by the number of bed days occupied. Neither the cost/resource boundary adopted in the analysis, nor the source of cost data was reported. The resource use was collected from February 2000 to January 2001. No price year was reported, but it is likely to have been 2000.
Statistical analysis of costs The costs were treated deterministically.
Indirect Costs The indirect costs were not included.
Sensitivity analysis No sensitivity analyses were performed.
Estimated benefits used in the economic analysis See the 'Effectiveness Results' section.
Cost results The median monthly transfusion costs were 81.32 before and 49.60 after the introduction of the new transfusion policy.
The total annual costs were 848,054.01 before and 600,230.47 after the new transfusion indications. Thus, the new protocol led to cost-savings of approximately 450,000.
Synthesis of costs and benefits Not relevant as a cost-consequences analysis was conducted.
Authors' conclusions A threshold platelet count of less than 10 x 10^9/L for prophylactic platelet transfusions proved to be safe in patients being treated for haematological malignancy who were not actively bleeding or septic. In cases where additional risk factors were present, the most appropriate threshold platelet count was less than 20 x 10^9/L, and greater than 50 x 10^9/L in the presence of major bleeding complications. Such indications for platelet transfusion led to potential cost-savings.
CRD COMMENTARY - Selection of comparators The rationale for the choice of the comparator was clear. A platelet count of less than 20 x 10^9/L was selected since it represented the standard threshold before the introduction of a new transfusion policy. You should decide whether it represents a valid comparator in your own setting.
Validity of estimate of measure of effectiveness The analysis of effectiveness used a prospective case-control study, which was appropriate for the study question. The study sample was representative of the study population. However, selection bias and confounding factors may have affected the effectiveness analysis, given that no randomisation was performed to allocate the patients to the study groups. In addition, the study groups were not shown to have been comparable at baseline, and there were no details on the retrospective sample of patients partially used in the effectiveness analysis.
Validity of estimate of measure of benefit No summary benefit measure was used in the economic analysis. The analysis was therefore categorised as a cost-consequences study.
Validity of estimate of costs The perspective adopted in the study was not reported. Only the costs strictly related to transfusion were included in the analysis. The indirect costs were not considered. The costs were treated deterministically and no sensitivity analyses were conducted. The cost estimates were fairly specific to the study setting. Discounting was not relevant. The unit costs and the source of the cost data were not reported.
Other issues The authors compared their findings with those from other studies, but did not address the issue of the generalisability of the study results to other settings. The external validity of the analysis was fairly low as no sensitivity analyses were conducted. The study enrolled patients receiving intensive chemotherapy for haematological malignancies, and this was reflected in the conclusions of the analysis.
Implications of the study The authors noted that the more stringent transfusion policy would result in cost-savings and fewer risks of transfusion-associated immunological complications.
Source of funding Supported by Lilly Research Centre, Hologic, Novartis, and Roche.
Bibliographic details Callow C R, Swindell R, Randall W, Chopra R. The frequency of bleeding complications in patients with haematological malignancy following the introduction of a stringent prophylactic platelet transfusion policy. British Journal of Haematology 2002; 118(2): 677-682 Indexing Status Subject indexing assigned by NLM MeSH Adolescent; Adult; Aged; Clinical Protocols; Female; Hematologic Neoplasms /drug therapy /economics; Hemorrhage /economics /etiology /prevention & Humans; Male; Middle Aged; Platelet Count; Platelet Transfusion /economics /methods; Prospective Studies; Retrospective Studies; Risk Factors; Thrombocytopenia /prevention & control; control AccessionNumber 22002001338 Date bibliographic record published 31/07/2003 Date abstract record published 31/07/2003 |
|
|
|