Introduction
Intravenous immunoglobulin (IVIg) is a common therapy for patients with immune thrombocytopenia (ITP). The initial response rate for IVIg is 80%1 and is typically rapid, with some patients responding in 24 hours, although usually in 2–4 days.2 When IVIg is used alone, the response is relatively short, averaging around 2–4 weeks. Potential side effects include headache, renal failure, thrombosis and transfusion-transmitted infection. The cost of IVIg is significant, averaging £400 for 10 g.3 Historic dosing regimens for IVIg are either 1 g/kg/day for 1–2 days or 0.4 g/kg/day for 5 days.4 There are data to suggest an increased likelihood of response with 1 g/kg/day for 1–2 days than with 0.4 g/kg/day for 5 days.5 Recent guidance from NHS England recommends 1 g/kg for 1 day, with a second dose of 1 g/kg at 7 days only if there is failure to achieve a haemostatically adequate platelet count.6 Using the optimal dosing regimen is important for maximum efficacy, the avoidance of side effects and prudent healthcare.
HaemSTAR (Haematology Specialty Trainee Audit and Research) is a UK-wide network of clinical haematology registrars that is supported by the National Institute of Health Research (NIHR) Haematology Clinical Research Network (CRN). We have members in each NIHR local CRN who coordinate local research activity and involvement of other participants as is needed. Our overarching aim is to promote clinical research in non-malignant haematology. One way that we intend to do this is by enabling effective transition of worthy local audits to a national scale.
Methods
This project aimed to audit the IVIg prescribing practices for treatment of ITP in the UK. Data from a 5-year period between 2013 and 2018 were eligible for inclusion. The primary outcome measure was the proportion of IVIg treatments that were dosed according to the 2011 American Society of Hematology guidelines.4 We also collected data on concomitant treatments and platelet count responses. We aimed to use this project to develop a generalisable methodology for future mass participation audits in non-malignant haematology.
With competitively won support of a data manager from the West Midlands Local CRN, we set up a data collection tool on a secure server running the Research Electronic Data Capture (REDCap) web application.7 With the help of our network, in late 2018, 134 collaborators across 39 hospital sites inputted data from the IVIg treatment episodes of 978 adult patients with ITP, over the course of just 80 days. This was all at no extra financial cost to the NHS.
Results and discussion
Nine hundred and fifty-six treatment episodes of IVIg were recorded with enough data for inclusion in the assessment of the primary outcome measure. Of these, 671 (70.2%) used the recommended dose of 1 g/kg/day, and 324 of these 671 (48.2%) were either given on a single day, or had a second dose after an adequate interval to allow for a response assessment. Three hundred and forty-seven (51.7%) treatments involved the use of additional doses given in a manner not endorsed by the guidelines; 324 had IVIg over two consecutive days, three were dosed over 5 days and 20 received a different dosing regimen. The platelet response following treatment with 1 g/kg on a single day was non-inferior to when IVIg was given over two consecutive days.
Not only do these data suggest that we may be spending more money than we should and exposing our patients to unnecessary risk by using significantly more IVIg than is recommended to treat ITP, but they also show that it is possible to collect valuable health data rapidly utilising minimal resources, by coordinating audit activity across the country with research networks such as HaemSTAR. We intend to repeat this national audit model annually with other important questions in haematology.
- © Royal College of Physicians 2019. All rights reserved.
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