Common co-morbidities in polymyalgia rheumatica and giant cell arteritis: cross-sectional study in UK Biobank

Objective The aim was to determine prevalent co-morbidities in cases with PMR or GCA compared with matched controls.Methods This was a nested, cross-sectional case-control study within the UK Biobank, which recruited participants aged 40-69 years. Case status was defined as self-reported prior diagnosis of PMR or GCA. Ten controls per case were matched for age, sex, ethnicity and assessment centre. Associations with selected self-reported co-morbidities were studied using conditional logistic regression.Results Of PMR (n = 1036) or GCA (n = 102) cases, 72% were female, 98% White, and 58% reported current use of glucocorticoids. Mean age was 63 years. At the time of the assessment visit, compared with controls, PMR/GCA cases were more likely to report poor general health and at least several days of low mood in the past 2 weeks. PMR was associated with hypothyroidism [odds ratio (OR) = 1.34; 95% CI = 1.07, 1.67] and ever-use of HRT (OR = 1.26; 95% CI = 1.07, 1.47). Regarding common co-morbidities, PMR and GCA were both associated with hypertension (PMR: OR = 1.21; 95% CI = 1.06, 1.39; GCA: OR = 1.86; 95% CI = 1.23, 2.81) and cataract (PMR: OR = 1.51; 95% CI = 1.19, 1.93; GCA: OR = 3.84; 95% CI = 2.23, 6.60). Additionally, GCA was associated with depression (OR = 3.05; 95% CI = 1.59, 5.85). Neither condition was associated with diabetes.Conclusion Participants with a history of PMR/GCA, including those not currently taking glucocorticoids, rated their health as poorer than matched controls. Some previously described disease associations (hypothyroidism and early menopause) were replicated. Hypertension and cataract, both of which can be exacerbated by long-term glucocorticoid therapy, were over-represented in both diseases, particularly GCA. What does this mean for patients?Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) are conditions that are often thought of as affecting older people. To manage these conditions, doctors prescribe long-term steroid treatment. We looked at a database from the UK Biobank study of half a million UK residents aged 40-69 years. In this database, there were 1036 people with PMR and 102 with GCA. We compared each of these people with PMR/GCA with 10 others of the same age and sex who did not have these conditions. We found that people with PMR/GCA had more general health problems and had low mood more often than people without these conditions. Depression was also seen more often in people with GCA than in people without GCA. People with PMR/GCA were also more likely to have high blood pressure and cataract. These are known side-effects of steroid treatment. People with PMR had higher rates of hypothyroidism and were also more likely to have used hormone replacement therapy. Other studies have found similar results. We still do not fully understand why this is. This study focused on people who were diagnosed with PMR or GCA at a younger age than usual. This patient group has not been studied much before. Our findings show that we need to pay attention to the physical and mental health needs of these patients.