The ratio of serum human nonmercaptalbumin (HMA) to human mercaptalbumin (HNA) may be a good indicator of systemic oxidative stress and a significant predictor of complications and disability in elderly patients with diabetes, according to study results published in Metabolism.

Human serum albumin, the most abundant protein in blood, is a radical-scavenging antioxidant that exists in 2 forms: HMA (reduced form) and HNA (oxidized form). In the current study, researchers investigated the association between the ratio of HNA to HMA plus HNA (HNA%) and oxidative stress, as well as the predictive value of this ratio for activities of daily living disability.

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The study included 126 elderly patients (aged ≥70 years) with diabetes treated at Yukuhashi Central Hospital in Japan between April 2018 and June 2018.

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Statistical analysis showed a significant association between serum bilirubin and albumin levels, 2 major endogenous antioxidants, and HNA% in elderly patients with diabetes (P =.007 and P =.004, respectively), thus supporting the theory that HNA% may be a good indicator of systemic oxidative stress. Chronic renal failure and hypertension were also significant determinants of HNA% (P =.009 and P <.001, respectively).

In a model that used HNA% alone, the ratio was found to be a significant determinant of activities of daily living disability (odds ratio [OR], 1.158; 95% CI, 1.077-1.244; P <.001). A model that incorporated HNA% and age showed both were significant determinants of activities of daily living disability (OR, 1.160 [95% CI, 1.069-1.268; P <.001] and 1.258 [95% CI, 1.110-1.427; P <.001], respectively). The receiver operating characteristic analysis showed that the area under the curve was 0.765 in the first model and 0.866 in the second model.

The study had several limitations, including its relatively small sample size, cross-sectional design, lack of comparison with other oxidative-stress markers, and inclusion of only elderly patients.

The researchers concluded that their results “strongly suggest that the ratio of HNA to (HMA+HNA) has clinical utility.”


Fukuhara S, Yasukawa K, Sato M, et al. Clinical usefulness of human serum  nonmercaptalbumin to mercaptalbumin ratio as a biomarker for diabetic complications and disability in activities of daily living in elderly patients with diabetes [published online October 29, 2019]. Metabolism. doi:10.1016/j.metabol.2019.153995