Increase in urine albumin-to-creatinine ratio as one of the earliest markers of renal damage in patients with hypertension and type 2 diabetes mellitus

Abstract

Background. The combination of hypertension and type 2 diabetes mellitus (T2DM) is associated with a particularly high risk of cardiovascular and renal complications. In accordance with current international guidelines, two criteria are used to diagnose chronic kidney disease (CKD): estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (ACR). However, at present, the nature and stages of changes in urine ACR and their relationship with changes in eGFR in hypertensive patients with T2DM have not been sufficiently studied. The purpose was to investigate the frequency and severity of increased urine ACR in hypertensive patients with T2DM. Materials and methods. We examined 44 patients with stage II hypertension grade 2–3 and T2DM aged 40 to 64 years: 20 (45 %) men, 24 (55 %) women. The examination was carried out using standard clinical, anthropometric, laboratory and instrumental methods. Diagnosis of hypertension, T2DM, cardiovascular diseases, their risk factors, CKD and categories of changes in eGFR and albuminuria were assessed in accordance with European and Ukrainian guidelines. eGFR was calculated using the CKD-EPI equation, taking into account serum creatinine levels; albuminuria was diagnosed by assessing ACR in the morning urine. Results. When analyzing changes in eGFR, 41 % of hypertensive patients with T2DM had a decrease in eGFR to G3a category, which indicates the presence of kidney damage as a target organ. Analysis of changes in urine ACR allows us to identify kidney damage as a target organ (a moderate increase in urine ACR to A2 category) in a significantly larger proportion of patients — 65 % of people. A moderate increase in urine ACR is diagnosed not only in most hypertensive patients with T2DM with a decrease in eGFR to G3a category (89 % of cases), but also in 55 % of individuals with a slight decrease in eGFR (G2 category), as well as in 25 % of patients with normal or high eGFR. Determining the risk of CKD progression based on simultaneous analysis of eGFR and urine ACR indicates that the vast majority of hypertensive patients with T2DM (72 %) have an increased risk of CKD progression, and only less than a third can be classified as those at risk of CKD progression. Conclusions. An increase in urine ACR can be considered as an earlier marker of kidney damage in hypertensive patients with T2DM than a decrease in eGFR, determined by the level of creatinine in the blood serum. Evaluation of urine ACR should be carried out in addition to the determination of eGFR in all patients in this category in order to diagnose kidney damage as early as possible and predict the risk of CKD progression and cardiovascular complications.

Keywords

• hypertension
• type 2 diabetes mellitus
• chronic kidney disease
• estimated glomerular filtration rate
• urine albumin-to-creatinine ratio