New-onset glucocorticoid (GC)-induced glucose intolerance is prevalent, and patients — even persons without diabetes — should be screened via oral glucose tolerance tests (OGTTs), according to research results published in Rheumatology.
To clarify which patients should undergo an OGTT, researchers sought to understand the prevalence and risk factors of new-onset glucose metabolism impairment in patients on long-term GC treatments.
The total study population included 150 consecutive adult patients (mean age, 59.5±14 years; 125 women) with systemic connective tissue diseases who were on GC therapy (daily dose, ≤10 mg) for >3 months between April 2015 and January 2019. Participants did not have diabetes and were not treated with glucose-lowering drugs.
Oral glucose tolerance test results identified normal glucose tolerance in 102 participants (Group 1). Isolated impaired fasting glucose, isolated impaired glucose tolerance, combined impaired fasting glucose and impaired glucose tolerance, and diabetes were diagnosed in 7, 29, 7, and 5 participants, respectively. In total, 32% of participants were diagnosed with new-onset glucose metabolism impairment and 20% had either impaired glucose tolerance or diabetes diagnosed exclusively via the OGTT without impaired fasting glucose (Group 2). Patients in group 2 were significantly older, had a higher body mass index, higher trunk fat percentage, higher glycated hemoglobin, and higher postload insulin concentration at 90 and 120 minutes. No differences in total cholesterol, low- or high-density lipoprotein cholesterols, or triglycerides were noted between groups.
Investigators performed a stepwise logistic regression analysis to determine which baseline factors were predictive of glucose metabolism impairment in participants without impaired fasting glucose. Variables — including age, sex, current and cumulative GC doses, time of treatment, type of GC, body mass index, waist circumference, trunk fat percentage, weight gain during therapy, fasting insulin concentration, and others — were included in a univariate analysis. Increased age was significant in both univariable and multivariable analyses (odds ratio [OR] 1.06; 95% CI, 1.02-1.1; P =.003 and OR 1.05; 95% CI, 1.01-1.09; P =.005).
Connective tissue diseases, excluding rheumatoid arthritis, did not reach the significance threshold in the univariate model.
In the multivariable model, only age and trunk fat percentage were significant factors for the occurrence of either impaired glucose tolerance or diabetes in the OGTT. Participants aged ≥50 years had a nearly 4-fold higher risk of having impaired glucose tolerance (OR 3.84; 95% CI, 1.03-14.23; P =.04) compared with an increase of 1 percentage point of trunk fat percentage (OR 1.09; 95% CI, 1.03-1.16; P =.006).
Study limitations include the small number of participations with disease activity score 28-joint count C-reactive protein values available.
“To the best of our knowledge, the present OGTT screening study is the first one performed in a large number of patients chronically treated with mainly low doses of GCs,” the researchers concluded. “The question whether, and if so when, OGTT should be repeated is open for further studies.”
Nowak KM, Rdzanek-Pikus M, Romanowska-Próchnicka K, Nowakowska-Płaza A, Papierska L. High prevalence of steroid-induced glucose intolerance with normal fasting glycaemia during low-dose glucocorticoid therapy: An oral glucose tolerance test screening study [published online November 30, 2020]. Rheumatology. doi:10.1093/rheumatology/keaa724