Ig Overused in Immune Thrombocytopenia, Flash Mob Audit Shows

Liam Davenport

April 02, 2019

GLASGOW — Immune thrombocytopenia (ITP) patients in the UK are not being given intravenous immunoglobulin (IVIg) in line with current recommendations, potentially exposing them to risks, showed researchers in a novel form of audit presented at the British Society for Haematology (BSH) Annual Scientific Meeting.

Immune thrombocytopenia patients in the UK have traditionally been given IVIg either as 1g/kg per day for 1–2 days or 0.4 g/kg per day for 5 days.

In a move that attracted some controversy, NHS England recently followed the 2011 American Society of Hematology practice guideline for immune thrombocytopenia in recommending IVIg be given as a single1g/kg dose, with a second dose given more than 24 hours later, if necessary.

Novel Research Technique

To examine current IVIg use in the UK, the team developed a novel research technique in which physicians participated en masse in a national audit, each collecting a relatively small amount of health data over a short period of time, to minimise resource utilisation, while creating a large overall dataset.

Likened to a 'flash mob’, in which people assemble suddenly, briefly perform an act and then quickly disperse, they recruited 134 registrars from 39 centres across Great Britain, who inputted data on 978 patients over a total of just 80 days.

The findings showed only approximately 70% of immune thrombocytopenia patients were given the recommended dose of IVIg, and only about half of those received it on a single day, or with a sufficient gap to judge the response.

Dr Phillip Nicolson, a clinical lecturer at the University of Birmingham, and haematology registrar at University Hospitals Birmingham NHS Foundation Trust, led the research.

He said that the study showed that "mass participant research activity is possible, it can be done quickly, and with minimal cost".

More crucially for clinical practice, it also demonstrated that "we are probably exposing patients with ITP to more intravenous immunoglobulin than necessary".

'Fascinating Method'

Dr Patrick Carrington, consultant haematologist at Trafford General Hospital, Manchester, and a former president of the British Society of Haematology, co-chaired the session.

He told Medscape News UK that the study is "a fascinating method for doing a nationwide audit in a very small amount of time".

Dr Carrington said that the study was borne out of the 2017 BSH Annual Meeting and funded by the National Institute of Health Research (NIHR) as "a way of getting registrars interested in the research concept".

For Dr Nicolson, "the most logical way to go about this was to recruit registrars and mentor consultants in each region of the UK".

The resulting network, known as HaemSTAR, consists of at least one registrar in each of the NIHR’s local clinical research networks in England, Scotland and Wales, allowing research activity to be communicated and coordinated across the country, "and, importantly, this can be done quickly".

Dr Nicolson explained that, as all doctors are required to be involved in audit, the question them became: "Why not do this in a coordinated way, so that we can use the same amount of effort to collect a much more meaningful dataset than is normally done when we do audits individually at individual trusts?"

Consequently, the central steering committee set up the audit protocol, developed the data collection forms, piloted the audit "to iron out any niggles", and then helped sites set it up with their audit departments.

Study Details

They recruited a total of 134 investigators across 39 sites, gathering a total of 1469 IVIg treatment episodes in 978 patients with immune thrombocytopenia over an 80-day period between October and December 2018.

Limiting the analysis to first treatments, the team identified 933 evaluable episodes, 670 of which involved a dose of 1g/kg and the remainder a different dosing regimen.

Among the 670 episodes, the dose was given on a single day, or a sufficient gap was left between doses to allow an assessment of response, in 322 cases.

The other 348 cases were characterised by doses being given on 2 or more consecutive days, and so not in line with the guidelines.

While the vast majority of patients had an indication for IVIg recorded in their notes in line with best practice, no reason was apparent in 6.4% of cases.

Dr Nicolson said that 35.7% of patients had a complete response, defined as a platelet count of ≥100 on two separate occasions at least 7 days apart, while 29.9% had a partial response, defined as a platelet count of ≥30, and 34.4% had a less than partial response.

There was no significant difference in overall platelet responses over time between patients given IVIg in line with current recommendations and those treated on 2 or more consecutive days.

The researchers said that these findings suggest not only that "we may be spending more money than we should be, and exposing our patients to unnecessary risk, by using significantly more IVIg than is recommended to treat immune thrombocytopenia but they also show that it is possible to rapidly collect valuable health data utilising minimal resources by coordinating audit activity across the country with research networks such as HaemSTAR".

Next, Dr Nicolson and his colleagues would like to look further into the data for associations that might predict response to IVIg, and use the findings to design a prospective study.

In addition, they would like to take the study methodology and apply it to other disease areas and specialties.

The research was supported by the National Institute of Health Research.

Nicolson discloses research grant funding from the British Heart Foundation, and industry support from Rigel, Novartis, Principia Biopharma.

BSH 2019: Abstract BSH19-OR-009. Presented April 1.

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