Systemic sclerosis in the UK: what is the disease burden and are there associations with other serious health outcomes?

Application Number
17_109
Lay Summary

Systemic sclerosis (SSc) is a disease which in its more serious form, affects the skin and internal organs through the immune system and the connective tissue. While some work has been done to estimate the number of new and existing cases of this disease in different areas of the UK, these estimates are lower than those found in Europe and the US. This suggests underreporting or a lower disease burden in the UK.

SSc may predispose patients to developing other diseases: greater knowledge about this is needed to inform patient care. For example, the burden of cancer may be greater in patients with SSc, but few studies have fully investigated this link. It has been found that some cancers (particularly breast) occur before a diagnosis of SSc whereas other cancers (oropharyngeal, oesophageal, lung) occur after SSc diagnosis: this relationship needs to be looked at in more detail. Increased rates of other serious diseases that arise due to damage to blood vessels supplying the heart and brain in those with SSc must also be considered and evaluated. This study will use national healthcare databases to describe the disease burden of SSc and investigate potential associations between SSc and other serious diagnoses.

Technical Summary

This study will investigate the incidence and prevalence of systemic sclerosis (SSc) in the UK. Cohort studies will be used to investigate serious outcomes: people with SSc will be matched to those who do not have SSc by age, sex, GP practice and calendar time will be accounted for. The outcomes investigated in separate studies will be cancer, myocardial infarction, cerebrovascular disease, peripheral vascular disease and pulmonary hypertension. Time to diagnosis of these outcomes and death will be compared using survival analysis. Covariates including smoking, alcohol, BMI, comorbidities and co-prescribing will be adjusted for.

The temporal relationship between cancer and SSc is less well understood than in other diseases: in some patients cancer pre-dates the diagnosis of SSc and this could be a factor in the development of SSc. This will be investigated using a case control study where the cases have an incident diagnosis of SSc and the controls do not, cases and controls will be matched as before. The analysis will use logistic regression and backdating of the index date to investigate this further. Where patients have a diagnosis of cancer and SSc at similar time points, inclusion in the analytical studies may not be possible.

Collaborators

Anita McGrogan - Chief Investigator - University of Bath
Anita McGrogan - Corresponding Applicant - University of Bath
Alison Nightingale - Collaborator - University of Bath
John Pauling - Collaborator - Royal National Hospital For Rheumatic Diseases
Julia Snowball - Collaborator - University of Bath
Neil McHugh - Collaborator - University of Bath

Linkages

HES Admitted Patient Care;HES Outpatient;NCRAS Cancer Registration Data