High prevalence of undiagnosed impaired glucose tolerance in patients with rheumatoid arthritis

OBJECTIVES: Although the risk of diabetes mellitus has been recognised in rheumatoid arthritis, undiagnosed dysglycaemia remained under-reported. The study aimed to determine the prevalence and associated factors of dysglycaemia among patients with rheumatoid arthritis, utilising the oral glucose tolerance test. METHODS: This cross-sectional study involved patients with rheumatoid arthritis, aged ⩾30 years. Following an oral glucose tolerance test, they were divided into two: dysglycaemia and normoglycaemia. Demographic and laboratory parameters were compared using logistic regression analyses. RESULTS: There were 35.5% (55/155) patients with dysglycaemia (including 25.8% impaired glucose tolerance, 7.1% diabetes mellitus and 1.9% with both impaired fasting glucose and impaired glucose tolerance). Patients with dysglycaemia were heavier (65.5 ± 12.3 versus 60.7 ± 10.6 kg, p = 0.01), had wider waist (89.0 ± 12.5 versus 83.1 ± 9.6 cm, p < 0.01), lower high-density lipoprotein cholesterol (1.4 ± 0.3 versus 1.5 ± 0.4 mmol/L, p = 0.02), higher triglyceride (1.3 (0.9–1.8) versus 0.9 (0.8–1.2) mmol/L, p < 0.01) and intercellular adhesion molecule-1 (361.79 (290.38–481.84) versus 315.92 (251.45–407.93) ng/mL, p = 0.01). History of smoking (odds ratio: 5.70, confidence interval: 1.27–25.7), elevated triglyceride (odds ratio: 2.87, confidence interval: 1.33–6.22) and intercellular adhesion molecule-1 (odds ratio: 1.003, confidence interval: 1.001–1.006) were significantly associated with dysglycaemia. CONCLUSIONS: Prevalence of undiagnosed dysglycaemia, particularly impaired glucose tolerance, was high in these patients with rheumatoid arthritis, using a 75-g oral glucose tolerance test, which was not associated with disease activity or corticosteroid use. Those with high triglyceride, history of smoking and elevated intercellular adhesion molecule-1 were the two significant predictors for dysglycaemia in our patients with rheumatoid arthritis. Oral glucose tolerance test could be an important laboratory investigation for dysglycaemia in these high-risk patients.