TTP is a rare disorder where clots form in the small blood vessels of the body, potentially resulting in a lack of blood supply to organs leading to tissue death or in extreme cases organ failure. There are two forms of the disease: an inherited form (congenital TTP [cTTP]) and an acquired form (idiopathic TTP [iTTP]), which is more common and is often triggered by factors such as infections or pregnancy. Following onset, the disease can progress rapidly without appropriate treatment and is associated with a high mortality rate. There is a lack of evidence reporting the resource use during an episode of TTP in the current literature. Furthermore, if treated and individuals survive, they may experience recurrences in the future. It is unclear how frequently recurrences occur and what the level of resource use is between episodes. Capturing this will help to more accurately estimate the impact any future treatment may have on managing the disease. For this study we wish to find the number of people with TTP using the Clinical Practice Research Datalink (CPRD) and Hospital Episode Statistics (HES) datasets. We will compare the resource use in the TTP population to a clinically similar population (for example in terms of age and gender) without TTP to estimate the cost impact. We will also aim to capture the frequency of episodes over time and the impact of TTP in specific subgroups (iTTP, cTTP, and pregnant population with TTP).
TTP is a rare blood disorder characterised by platelet-rich thrombi formation within smaller blood vessels resulting in tissue ischaemia. Evidence suggests that there is a link between TTP development and a deficiency in the ADAMTS13 enzyme. There are two forms of TTP: cTTP, where mutations in the gene encoding ADAMTS13 results in reduced or changed activity of the enzyme, and iTTP, where environmental factors such as pregnancy or HIV infection may trigger antibodies which block the action of ADAMTS13. TTP onset often occurs rapidly and can last from days to weeks. Due to how the disease manifests it can lead to a myriad of health consequences of varying severity that individuals may clinically present with, making prompt diagnosis difficult. Survival without treatment is also estimated to be less than 10%. Whilst mortality risk reduces with treatment, the disease is often episodic with 20-50% of individuals experiencing a recurrence. Therefore, individuals are often subject to lifelong monitoring so that any recurrences can be identified and treated as early as possible. Furthermore, there is widespread uncertainty around the rates of recurrences, and the management of disease during remission, for those who survive the initial episode. A better understanding of the true resource use and natural history of people with TTP, including organ failure, may help to capture the unmet need and the potential cost impact of any future treatments more accurately. We wish to use the CPRD linked to the HES datasets to identify patients who have TTP. Patients found in the CRPD and HES datasets will be compared with a matched non-TTP population to estimate differences in cost and resource use burden to the healthcare system. We wish to also explore the impact of TTP within specific subgroups (iTTP, cTTP, and pregnant population with TTP).
Patient demographics (age, sex, ethnicity, previous TTP diagnosis, previous organ damage, previous TTP-related treatment); health resource outcomes (appointments in primary care, prescriptions issued in primary care, inpatient admissions, inpatient length of stay, inpatient HRG codes, outpatient appointments, A&E attendances, A&E HRG codes, TTP-related treatment); average number of episodes; average time between episodes; duration of episodes; pregnancy during acute episodes; organ damage events (overall, by type, during an acute episode); disease prevalence; mortality.
Oliver Heard - Chief Investigator - Takeda UK Limited
Hayden Holmes - Corresponding Applicant - York Health Economics Consortium Ltd ( YHEC )
Erin Barker - Collaborator - York Health Economics Consortium Ltd ( YHEC )
Heather Riley - Collaborator - York Health Economics Consortium Ltd ( YHEC )
Indraraj Umesh Doobaree - Collaborator - Takeda UK Limited
Joe Moss - Collaborator - York Health Economics Consortium Ltd ( YHEC )
Monica Garrett - Collaborator - York Health Economics Consortium Ltd ( YHEC )
Sarah Campbell-Hill - Collaborator - Not from an Organisation
Stuart Mealing - Collaborator - York Health Economics Consortium Ltd ( YHEC )
Angel Varghese - Collaborator - York Health Economics Consortium Ltd ( YHEC )
Heather Riley - Collaborator - York Health Economics Consortium Ltd ( YHEC )
James Scott - Collaborator - York Health Economics Consortium Ltd ( YHEC )
Laura Kelly - Collaborator - York Health Economics Consortium Ltd ( YHEC )
Monica Garrett - Collaborator - York Health Economics Consortium Ltd ( YHEC )
Niamh Hogan - Collaborator - Takeda UK Limited
Oliver Heard - Collaborator - Takeda UK Limited
Sarah Campbell-Hill - Collaborator - Not from an Organisation
Stuart Mealing - Collaborator - York Health Economics Consortium Ltd ( YHEC )
Indraraj Umesh Doobaree - Collaborator - Takeda UK Limited
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;CPRD Aurum Pregnancy Register