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SF | NEPHROLOGY
March 2021 | Vol. 21 No. 3 www.medicalacademic.co.za
Photo credit: Shutterstock.com
This article was independently sourced by Specialist Forum.
Diabetic nephropathy complexities
Hypertension is common among patients with diabetes. Hypertension increases their risk of chronic kidney disease (CKD) onset and progression, as well as cardiovascular (CV) morbidity and mortality.1,2
M
ore than 50% of patients with diabetes have hypertension, of whom 50% will develop some degree of renal impairment over time. A meta-analysis of 102 studies showed that patients with diabetes have a two-fold increase risk for CKD, coronary heart disease, major stroke, and mortality.1,3 In patients with diabetes, hypertension is defined as a systolic BP (SBP) ≥130mmHg or a diastolic BP (DBP) ≥80mmHg. The 2020 American Diabetes Association guideline recommends a BP target of <130/80mmHg for patients at high or very high CV risk (with atherosclerotic cardiovascular disease or 10year atherosclerotic CVD risk ≥15%), if it can be safely attained, while for those at lower risk for CVD (10-year atherosclerotic CVD risk <15%) a target of <140/90 mmHg is recommended.1,2,4
Diabetic nephropathy Kidney damage caused by diabetes – diabetic nephropathy – is the main cause of CKD and the leading cause of end stage renal disease (ESRD) in this patient population. 2,5 Although the mechanism of hypertension
in diabetic nephropathy is complex and incompletely understood, it has been postulated that it may be the result of excess sodium retention, activation of the sympathetic nervous and renin-angiotensin-aldosterone systems (RAAS), endothelial cell dysfunction, and increased oxidative stress. 2 The RAAS system plays a pivotal role in the regulation of BP. Apart from hypertension, the RAAS system is implicated in the pathogenesis and progression of numerous CV and renal pathologies, including structural cardiac remodelling, myocardial infarction, heart failure and CKD.6 Guidelines state that CKD can be attributed to diabetes in the presence of macroalbuminuria (>300mg/24 hr) or the presence of microalbuminuria (30mg300mg/24 hr) in the context of diabetic retinopathy or a history of diabetes exceeding 10 years. 2
Inhibition of RAAS system The inhibition of the RAAS system is the cornerstone of preventing diabetic neuropathy. The 2020 International Society of Hypertension
guideline recommends RAAS-inhibitors as first-line treatment in patients with diabetes and hypertension, because they reduce albuminuria in addition to BP. Calcium channel blockers (CCBs) and diuretics (loop-diuretics if estimated glomerular filtration rate <30 ml/ min/1.73m2) can be added, state the authors of the guideline.6,7 Angiotensin receptor blockers (ARBs) and ACE inhibitors (ACEIs) are the two major RAAS inhibitors. ARBs have been in clinical use since 1995. The efficacy and safety of ARBs as a potent antihypertensive agent have been shown in numerous studies.6,8 ARBs have been shown to be more effective than other traditional agents in reducing the onset of clinical proteinuria in individuals with both Type 1 Diabetes (T1DM) and Type 2 Diabetes (T2DM) as well as incipient nephropathy.13 The aim of the Program for Irbesartan Mortality and Morbidity Evaluation was to determine whether ARBs are effective in both preventing the development of clinical proteinuria and delaying the progression of nephropathy in T2DM. It consists of two large
