The Histiocytic diseases are rare but have potentially very serious consequences in affected individuals.
Researching them is challenging because of:
- a lack of accurate information on how new cases are recorded, diagnosed and registered across England;
- incomplete information about the occurrence and natural course of the disease;
- poor understanding of the reasons why these diseases occur; and
- the difficulty in identifying large enough numbers of cases to meaningfully answer research questions.
We intend to use high quality, routinely collected information from the National Health Service (collated by general practitioners, hospitals, and national registrations of rare diseases, cancer and deaths) to find out when, where and in which groups of people histiocytic diseases occur (with specific focus upon Langerhans cell histiocytosis, Malignant Histiocytosis, Erdheim-Chester disease and Haemophagocytic Lymphohistiocytosis) have occurred during the last 20 years across the whole of England. We will also investigate what happened to the groups of people with histiocytic diseases. We will be able to detect any inequalities in diagnosis and survival in relation to age, sex, social characteristics and geographical area. Our ultimate aim is to bring greater understanding of these rare diseases, facilitate early diagnosis, improve outcomes and the quality of life of patients.
There are few population-based studies examining the epidemiology of histiocytic diseases, due to the difficulty in identifying large enough numbers of cases. Routinely collected electronic health data from the UK National Health Service provides a potential opportunity to research these diseases. The objectives of this study therefore are to assess the occurrence of Langerhans cell histiocytosis (LCH), Malignant Histiocytosis (MH), Erdheim-Chester disease (ECD) and Haemophagocytic Lymphohistiocytosis/Haemophagocytic syndrome (HLH) as recorded in electronic health records in England between 2000 and 2018, and to measure the incidence, point prevalence and long-term outcomes.
We will determine LCH, MH, ECD and HLH from CPRD primary care, HES inpatients and Cancer Registry datasets. We will assess the extent of ascertainment of identified cases between the three datasets. Having assessed our case ascertainment, we will carry out incidence and mortality analyses for LCH, MH, ECD and HLH. We will analyse and describe trends over time and the known alterations in coding structures and algorithms of the recording of histiocytosis. We will examine the rates of new diagnoses (incidence) and point prevalence of LCH, MH, ECD and HLH by age, sex, socioeconomic status and region using Poison regression. We will also calculate the 30-day, 1 and 5-year survival. Cox regression will be used to calculate the hazard ratios and a Fine & Gray regression model will be used to estimate cause-specific mortality adjusting for the competing risk of death from other causes.
Incidence, point prevalence, all cause and cause specific mortality
Joe West - Chief Investigator - University of Nottingham
Joe West - Corresponding Applicant - University of Nottingham
Colin Crooks - Collaborator - University of Nottingham
Johann Visser - Collaborator - Cambridge University Hospitals
Judith Rankin - Collaborator - Newcastle University
Lu Ban - Collaborator - University of Nottingham
Lucy Ellis-Brookes - Collaborator - National Cancer Intelligence Network - NCIN
Mark Bishton - Collaborator - Nottingham University Hospitals
Mary Bythell - Collaborator - Public Health England
Peter Lanyon - Collaborator - Nottingham University Hospitals
Timothy Card - Collaborator - University of Nottingham
Vasanta Nanduri - Collaborator - West Hertfordshire Hospitals NHS Trust
HES Admitted Patient Care;NCRAS Cancer Registration Data;NCRAS Systemic Anti-Cancer Treatment (SACT) data;ONS Death Registration Data;Patient Level Index of Multiple Deprivation