Hypertension and diabetes mellitus management in kidney disease
Mercy Ezhil Rani
Clinical Educator, Kauvery Hospital, Hosur, Tamil Nadu
Introduction
Hypertension is the most common comorbidity in patients with CKD, affecting 67–92% of patients. The prevalence of hypertension increases with declining renal function. Control of hypertension is a major priority in the management of CKD and represents an important modifiable factor in slowing further loss of kidney function. Elevated blood pressure can occur as a result of CKD but is also a potent risk factor for CKD progression
Hypertension
Hypertension in kidney disease refers to high blood pressure that occurs as a result of kidney dysfunction or disease. The kidneys play a key role in regulating blood pressure by controlling fluid balance, sodium levels, and the release of hormones like renin. When the kidneys are damaged or diseased, they may not be able to regulate blood pressure effectively, leading to hypertension.
- Primary Hypertension (Essential Hypertension):
- Secondary Hypertension: This type of hypertension is directly caused by an underlying kidney condition.
Secondary Hypertension
- Chronic Kidney Disease (CKD): As kidney function declines, the kidneys may not be able to excrete enough sodium or regulate fluid balance, leading to high blood pressure.
- Renal Artery Stenosis: Narrowing of the arteries that supply blood to the kidneys can trigger high blood pressure due to reduced blood flow to the kidneys.
- Other kidney diseases: Conditions like polycystic kidney disease, glomerulonephritis, and diabetic nephropathy can also contribute to the development of hypertension.
Kidney Disease leading to Hypertension
kidney disease can also contribute to high blood pressure. Damaged kidneys may struggle to regulate blood volume and salt balance, leading to increased fluid retention and elevated blood pressure. Renin-Angiotensin-Aldosterone System (RAAS): When kidneys are damaged, they may release an excess amount of a hormone called renin, which triggers a chain reaction that leads to increased blood pressure.
Fluid retention: Impaired kidney function leads to the buildup of excess fluid in the body, which can raise blood pressure.
Hypertension as a Cause of Kidney Disease
High blood pressure is one of the leading causes of chronic kidney disease (CKD). When blood pressure is consistently elevated, it puts excess pressure on the blood vessels in the kidneys, causing damage over time. This damage can result in reduced kidney function and, if untreated, can progress to kidney failure.
Kidney damage: The small blood vessels in the kidneys become damaged and thickened, which affects the kidneys’ ability to filter waste and excess fluid properly. Glomerular damage: Hypertension can cause damage to the glomeruli (tiny filtration units within the kidneys), leading to protein leakage into the urine and further worsening kidney function.
Risk Factors of Hypertension in CKD
- Older age
- Overweight or obesity
- Increased risk of heart disease
- End-stage renal disease (ESRD)
Management
- Sodium restriction
- Diuretics
- Thiazide diuretics become less effective when the GFR is less than 30 mL/min
- Loop diuretics are preferred as initial therapy
- Antihypertensive therapy in proteinuria CKD
- Angiotensin inhibitors as first-line therapy
- Calcium Channel Blockers and diuretic with angiotensin-converting enzyme inhibitors
- (ACE inhibitors) or angiotensin II receptor blockers (ARBs)
- Antihypertensive therapy in non-proteinuria CKD with edema, initial therapy with a loop diuretic without edema, an ACE, and then add a dihydropyridine CCB
- Benefit from nocturnal therapy: Management of blood pressure in chronic kidney disease that goal blood pressure depends upon the degree of proteinuria:
- Proteinuric CKD, (500 mg/day or higher), the BP < 120/80 mmHg.
- Nonproteinuric CKD, (<500 mg/day), the BP < 140/90 mmHg.
- Isolated systolic HTN, systolic pressure <150 mmHg
- Proteinuria goal of less than 1000 mg/day
Diabetic Nephropathy
Diabetic nephropathy is a serious complication of type 1 diabetes and type 2 diabetes. It’s also called diabetic kidney disease. Diabetic nephropathy affects the kidneys’ usual work of removing waste products and extra fluid from the body. The best way to prevent or delay diabetic nephropathy is by living a healthy lifestyle and keeping diabetes and high blood pressure managed.
Diabetes as a Leading Cause of Kidney Disease
Diabetes is one of the most common causes of chronic kidney disease (CKD). High blood sugar levels, over time, can damage the blood vessels in the kidneys, affecting their ability to filter waste products and fluids from the body.
Damaged blood vessels: Consistently high blood sugar levels can damage the small blood vessels in the kidneys, particularly the glomeruli (the tiny filtration units in the kidneys). This damage leads to impaired kidney function.
Protein leakage: One of the earliest signs of diabetic nephropathy is the presence of protein (particularly albumin) in the urine. The kidneys are no longer able to retain protein properly, and it starts to leak into the urine. This is known as albuminuria.
Symptoms
- High blood pressure that gets harder to control.
- Swelling in the feet, ankles, or legs due to fluid retention.
- Frequent urination at night.
- Fatigue and feeling generally unwell.
- Loss of appetite.
- Nausea and vomiting.
- Foamy urine (indicating protein).
Stages of Diabetic Nephropathy
- Stage 1: Hyper filtration: In the early stages of diabetes, the kidneys may filter more blood than usual, a phenomenon known as hyper filtration. This stage usually doesn’t show any symptoms, but kidney damage begins to accumulate.
- Stage 2: Silent stage: No albuminuria
- Stage 3: Microalbuminuria: The kidneys begin to leak small amounts of protein into the urine, but the levels are not high enough to be detected in a routine urine test. This stage often goes unnoticed without regular screening for albumin in the urine.
- Stage 4: Macro albuminuria: At this stage, the kidneys leak larger amounts of protein (macro albuminuria) into the urine, and kidney function begins to decline. This is often detected through a urine test, and it signifies the worsening of kidney function.
- Stage 5: Kidney Failure (End-stage Renal Disease – ESRD): If the damage progresses without intervention, kidney function deteriorates to the point where the kidneys can no longer function properly. In this stage, patients may require dialysis or a kidney transplant.
Risk Factors
- Uncontrolled high blood sugar, also called hyperglycemia.
- Uncontrolled high blood pressure, also called hypertension.
- Smoking.
- High blood cholesterol.
- Obesity.
- A family history of diabetes and kidney disease.
Treatment of Diabetic Nephropathy
- Medications: Medications to control blood sugar (insulin and oral medications), blood pressure (ACE inhibitors, ARBs), and cholesterol levels may be used.
- Dialysis: In cases where kidney function declines significantly, dialysis may be necessary to perform the kidneys’ filtration functions artificially.
- Kidney transplant: In severe cases of kidney failure, a kidney transplant may be the best option for restoring kidney function.
Advance Treatment in Diabetic Nephropathy
- Sodium-Glucose Cotransporter-2 (SGLT2) Inhibitors: It can slow the progression of kidney disease, reduce the risk of kidney failure, and lower the incidence of heart failure hospitalizations in patients with diabetic nephropathy.
- Mineralocorticoid Receptor Antagonists (MRAs): Lower the risk of kidney failure and cardiovascular events.
- Glucagon-Like Peptide-1 (GLP-1) Receptor Agonists: Recently Food and Drug Administration approved to slow kidney disease progression.
Management
- Blood sugar control: Keeping blood sugar levels within target range through diet, exercise, and medication (e.g., insulin, oral medications).
- Blood pressure management: Medications like ACE inhibitors or ARBs (angiotensin receptor blockers) are commonly used to control high blood pressure and protect the kidneys.
- Regular screening: Kidney function should be monitored regularly through urine tests (checking for albumin) and blood tests (checking for creatinine and glomerular filtration rate or GFR).
- Dietary changes: A healthy diet low in salt, saturated fats, and protein can help prevent further kidney damage.
- Weight management: Maintaining a healthy weight can reduce the strain on both kidneys and overall health.
- Exercise: Regular physical activity can help improve blood sugar control, reduce blood pressure, and protect kidney health.
Complications
Complications of diabetic nephropathy can come on slowly over months or years.
- Body fluid buildup. This could lead to swelling in the arms and legs, high blood pressure, or fluid in the lungs, called pulmonary edema.
- A rise in the levels of the mineral potassium in the blood, called hyperkalemia.
- Heart and blood vessel disease, also called cardiovascular disease. This could lead to a stroke.
- Fewer red blood cells to carry oxygen. This condition also is called anemia.
- Pregnancy complications that carry risks for the pregnant person and the growing fetus.
- Damage to the kidneys that can’t be fixed. This is called end-stage kidney disease.
- Treatment is either dialysis or a kidney transplant.
