Background/Purpose: With the growing awareness of disease course of ankylosing spondylitis (AS) and recent development of novel treatments which might be the most effective for early stage of disease, there is an unmet need for markers that can assess disease activity more simply in those individuals at the highest risk for a bad outcome. Bath ankylosing spondylitis disease activity index (BASDAI) has been the most widely used clinical disease activity measure in AS. However, the BASDAI has no consideration for laboratory inflammatory markers. Furthermore, an elevated ESR or CRP is present in only about 40-50% of patients with active AS. Glycated albumin (GA) was initially viewed as an adjunct to glycated hemoglobin (HbA1c), but it has recently been reported that chronic inflammation is positively correlated with HbA1c level, whereas it is negatively associated with GA. We evaluated the availability of the ratio of HbA1c and GA as an adjunctive marker to the Ankylosing Spondylitis Disease Activity Score (ASDAS) already proposed.

Methods: A total of 58 non-diabetic AS patients who met the modified New York classification criteria were included. ESR, CRP, ASDAS-ESR, ASDAS-CRP, BASDAI, and patient’s global assessment (BASG) were assessed.

Results: The median [interquartile range, IQR] HbA1c/GA ratio was 0.42 [0.40, 0.44]. The medians [IQR] of A1C, GA. ESR, CRP, ASDAS-ESR, and ASDAS-CRP level were respectively 5.5 [5.3, 5.6] %, 13.1 [12.4, 13.8] %, 17.5 [6.0, 32.5] mm/hr, 1.5 [0.7, 6.4] mg/l, 2.44 [1.38, 3.03], and 1.92 [1.22, 2.59] in the patients with AS. HbA1c significantly correlated with ASDAS-ESR, ASDAS-CRP, BASDAI and BASG (r = 0.328, p < 0.05;  r = 0.356, p < 0.05; r = 0.326, p < 0.05; r = 0.440, p < 0.01, respectively). GA showed a weak negative association with ESR, CRP and ASDAS score, but there was no significant difference statistically. There were significant correlations between the ratio of HbA1c/GA and disease activity based on ASDAS in AS patients (for ASDAS-ESR, r = 0.367, p < 0.05; for ASDAS-CRP, r = 0.462, p < 0.01; for ESR, r = 0.417, p < 0.01; for CRP, r = 0.356, p < 0.05).

Conclusion: In patients with AS, HbA1c/GA ratio correlate with disease activity, and consequently combination of these parameters may serve as a better marker of disease severity.

Table  Correlation between HbA1c/GA ratio, HbA1c, GA. ESR, CRP, ASDAS-ESR, and ASDAS-CRP in 58 patients with AS

HbA1c, glycated hemoglobin A1c; GA, glycated albumin; ASDAS, Ankylosing Spondylitis Disease Activity Score; ESR, erythrocyte sedimentation rate; CRP, C-reactive protein; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASG, Bath Ankylosing Spondylitis Patient Global Score

r is determined by Spearman’s rank correlation test

Bold characters indicate a statistically significant difference with a p-value < 0.05, and r values ≥ 0.4

^# Statistical significance p < 0.05

^* Statistical significance p < 0.01

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-ratio-of-glycated-hemoglobin-a1c-hba1c-to-glycated-albumin-ga-is-correlated-with-ankylosing-spondylitis-disease-activity-score-asdas-in-non-diabetic-patients-with-ankylosing-spondylitis/