Both giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are age-associated diseases which appear to have an autoimmune basis. In GCA there is inflammation of the arterial wall and in PMR there is inflammation in and around the joints. In the case of GCA this often affects the blood supply to the eye, causing a variety of visual and ocular symptoms. Some patients with GCA develop irreversible visual loss.
The overlap between GCA and PMR remains somewhat controversial, but modern imaging studies reveal that a proportion of patients with a clinical diagnosis of PMR also have evidence of arterial inflammation very similar to that seen in GCA. Furthermore some patients who present initially with PMR later go on to develop clinical features of GCA. Both these diseases are treated with glucocorticoids, which can have substantial adverse effects, including diabetes, osteoporosis and glaucoma. Both GCA and PMR remain relatively under-researched and there is a need to build research capacity in these disease areas.
The data in UKBB may highlight potential associations of GCA and PMR that may stimulate further research into pathogenesis; some disease associations of GCA and/or PMR have been hypothesized or described in the literature and UKBB would be a good cohort in which to seek to test (or replicate) these. Describing the morbidity burden of individuals with a diagnosis of GCA and PMR, compared to people without these diseases, will also help to identify the health needs of this patient group.
We intend to perform a cross-sectional study to investigate associations of GCA and PMR within UKBB. Additionally, as a pilot study we wish to determine whether ocular imaging, including optical coherence tomography (OCT) and retinal vascular calibre measurements, reveals particular features of GCA/PMR.