Serum Albumin Modifies the Effect of Peripheral Blood Monocytes on Severity of Diabetic Nephropathy

Aims: To characterize clinical associations with peripheral blood immune populations, serum inflammatory markers, and diabetic nephropathy in persons with type 2 diabetes mellitus. Methods: We identified a cohort of clinically well-defined patients from a primary care clinic at a medium-sized academic medical center. We queried hospital records between 2018 and 2019 for complete blood counts with differentials, serum inflammatory markers, and urine microalbumin/creatine ratios. 198 patients met these criteria. We assessed univariable and multivariable associations between demographic, clinical, and peripheral blood predictors of kidney end-organ damage as determined by microalbumin/creatinine ratios or estimated glomerular filtration rate. All analyses used linear or logistic regression models. Results: Adjusted analyses demonstrated significant (p<0.01) associations between higher urine albumin-creatinine ratio and peripheral circulating monocytes independent of other established significant risk factors including blood pressure, hemoglobin A1c, age, and gender. We also identify serum albumin as an unexpected but potentially important modifying factor of kidney disease which interacts with monocytes. Conclusion: Circulating monocytes and serum albumin are significantly associated with diabetic nephropathy. These results support the potential role of the innate immune system in diabetic microvascular end-organ damage, and may be readily translatable clinical markers to incorporate into risk-assessment models for prognostication in diabetes.