277. Chronic Foot Problems in People with Gout: An Observational Study in Primary Care

Abstract

Background: Gout displays a remarkable predilection to affect the foot, particularly the 1st metatarsophalangeal joint. Chronic foot problems such as hallux valgus and great toe pain are also common in people with gout. Using baseline data from a primary care cohort, this study aimed to determine the prevalence and determinants of hallux valgus, foot pain and related disability in people with gout. Methods: All adults aged ≥18 years registered with 20 general practices in the West Midlands who had consulted their GP about gout or been prescribed allopurinol or colchicine in the preceding 2 years were mailed a questionnaire. The questionnaire included gout characteristics (duration, attack frequency, treatment), comorbidity, height, weight, mental health [Generalized Anxiety Disorder Assessment (GAD7), Patient Health Questionnaire (PHQ9)], and self-reported hallux valgus (validated linedrawing instrument). Foot pain was defined as reporting pain, aching or stiffness in the feet on most or all days in the past month, whilst disabling foot pain was assessed using the Manchester Foot Pain and Disability Index function subscale. The presence of tophi and serum uric acid (SUA) levels were ascertained from medical records. The prevalence of hallux valgus, foot pain and disabling foot pain in the mailed population were estimated by inverse-weighted logistic regression. Logistic regression was used to assess associations between socio-demographic, comorbid and gout-specific factors and hallux valgus, foot pain and disabling foot pain. For foot pain analyses, those with a current gout attack were excluded. Results: 1184 completed questionnaires were received (response 66%). Mean age was 65.6 years (S.D. 12.5); 476 (78%) were male. Responders were younger, less socio-economically deprived and more likely to be female than non-responders. Mean gout duration was 11.9 years (S.D. 12.1) and SUA 441 μmol/l (S.D. 116). 630 (56%) were currently taking allopurinol, 25 (2%) had tophi and 307 (27%) reported ≥3 attacks in the last year. Prevalence of hallux valgus in either foot was 36%, foot pain in the past month 22% and disabling foot pain 15%. Hallux valgus was associated with age (OR 1.47 per 10-year increase; 95% CI 1.26, 1.72) and female gender (2.03; 1.31, 3.15), but not BMI, socio-economics, co-morbid or gout characteristics. Foot pain in the past month was associated with age (1.25 per 10-year increase, 1.00, 1.55), higher BMI (BMI ≥30 1.96; 1.04, 3.68) and polyarticular attacks (1.86; 1.18, 2.94). Disabling foot pain was associated with older age (1.42; 1.08, 1.87), higher BMI (BMI ≥30 2.34; 1.09, 5.03) and ischaemic heart disease (2.44; 1.32, 4.51). Conclusion: Chronic foot problems are common in people with gout. Hallux valgus in gout has similar associations to the general population and does not appear to relate to disease-related factors. Foot pain in the past month associates with both disease and co-morbid characteristics whereas disabling foot pain associates with comorbidity.