From the Guidelines
Early detection of kidney disease is crucial, and the most recent guidelines recommend testing people at risk for and with chronic kidney disease using both urine albumin measurement and assessment of glomerular filtration rate (GFR) 1. The early signs of impaired renal function can be subtle and may go unnoticed without proper screening. These signs typically include:
- Increased fatigue
- Swelling in the ankles and feet (edema)
- Decreased urination or changes in urine appearance
- Increased blood pressure
- Persistent itching You might also experience nausea, decreased appetite, trouble concentrating, and muscle cramps, particularly at night. Laboratory findings often show elevated blood urea nitrogen (BUN) and creatinine levels, decreased estimated glomerular filtration rate (eGFR), protein or blood in the urine, and electrolyte imbalances. Regular screening is crucial, especially for those with risk factors like diabetes, hypertension, or family history of kidney disease. These early symptoms occur because kidneys are responsible for filtering waste products from blood, regulating fluid balance, and producing hormones that control blood pressure and red blood cell production. When kidney function declines, these processes become impaired, leading to the accumulation of waste products and fluid imbalances that manifest as the symptoms described. Early detection through routine blood and urine tests can significantly improve outcomes by allowing for timely intervention before permanent kidney damage occurs, as recommended by the latest guidelines 1. It is essential to note that the definition and classification of chronic kidney disease have been established, and the guidelines provide a framework for the evaluation and management of chronic kidney disease 1. However, the most recent and highest-quality study 1 should be prioritized when making recommendations. In clinical practice, the use of simplified MDRD equations to estimate GFR and the measurement of urinary albumin-to-creatinine or protein-to-creatinine ratios can help identify early renal dysfunction 1. Overall, early detection and intervention are critical in preventing the progression of kidney disease and improving patient outcomes.
From the FDA Drug Label
In patients with severe congestive heart failure whose renal function may depend on the activity of the renin-angiotensin-aldosterone system, treatment with angiotensin converting enzyme inhibitors, including lisinopril, may be associated with oliguria and/or progressive azotemia and rarely with acute renal failure and/or death In hypertensive patients with unilateral or bilateral renal artery stenosis, increases in blood urea nitrogen and serum creatinine may occur. Patients with acute myocardial infarction in the GISSI-3 trial treated with lisinopril had a higher (2.4% versus 1. 1%) incidence of renal dysfunction in-hospital and at six weeks (increasing creatinine concentration to over 3 mg/dL or a doubling or more of the baseline serum creatinine concentration). If renal dysfunction develops during treatment with lisinopril (serum creatinine concentration exceeding 3 mg/dL or a doubling from the pretreatment value)
The early signs of impaired renal function include:
- Oliguria (decreased urine output)
- Progressive azotemia (elevated levels of nitrogen waste products in the blood)
- Increases in blood urea nitrogen and serum creatinine levels
- A doubling or more of the baseline serum creatinine concentration or an increase in creatinine concentration to over 3 mg/dL 2
From the Research
Early Signs of Impaired Renal Function
The early signs of impaired renal (kidney) function can be identified through various methods, including:
- Screening for microalbuminuria using the spot urine albumin-to-creatinine ratio 3, 4
- Estimating glomerular filtration rate (GFR) in patients with type 2 diabetes 3
- Monitoring serum creatinine and potassium levels in patients receiving angiotensin-converting enzyme inhibitors or angiotensin receptor blockers 4, 5
- Checking for low levels of albumin (microalbuminuria) in the urine, which is a common indicator of diabetic nephropathy 4
Diagnostic Criteria
The diagnostic criteria for impaired renal function include:
- Results of two of three tests for microalbuminuria showing more than 30 mg per day or 20 mcg per minute in a three- to six-month period 4
- Elevated urinary albumin excretion, confirmed by repeated testing 6
- Reduced GFR, which can be estimated using various formulas 3, 7
Risk Factors
Certain risk factors can increase the likelihood of developing impaired renal function, including: