What to do about elevated creatinine (serum creatinine) levels confirmed 6 weeks apart, indicating impaired renal function?

From the Guidelines

If you have elevated creatinine levels confirmed 6 weeks apart, you should consult with a nephrologist promptly for a comprehensive evaluation and management plan. The first step will be to identify the underlying cause through additional tests including a complete metabolic panel, urinalysis, urine protein-to-creatinine ratio, renal ultrasound, and possibly a kidney biopsy in some cases 1. While awaiting specialist care, make immediate lifestyle modifications including limiting dietary sodium to 2-3g daily, moderating protein intake to 0.8g/kg body weight per day, staying well-hydrated, and avoiding nephrotoxic medications like NSAIDs and certain antibiotics. Some key points to consider in the management of elevated creatinine levels include:

• Blood pressure control is crucial, with a target below 130/80 mmHg typically achieved using ACE inhibitors or ARBs like lisinopril (10-40mg daily) or losartan (50-100mg daily) 1.
• These medications not only lower blood pressure but also reduce protein excretion and slow kidney disease progression.
• Regular monitoring of kidney function every 3-6 months will be necessary to track disease progression.
• Elevated creatinine indicates reduced kidney filtration capacity, which can result from various conditions including diabetes, hypertension, glomerulonephritis, or medication effects, making proper diagnosis essential for targeted treatment 1. It is essential to follow the most recent guidelines for the management of kidney disease, such as those provided by the KDIGO 2022 clinical practice guideline for diabetes management in chronic kidney disease 1.

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. If renal dysfunction develops during treatment with lisinopril (serum creatinine concentration exceeding 3 mg/dL or a doubling from the pretreatment value) then the physician should consider withdrawal of lisinopril. Evaluation of patients with hypertension, heart failure, or myocardial infarction should always include assessment of renal function.

Elevated Creatinine Levels:

• If a patient has elevated creatinine levels confirmed 6 weeks apart, indicating impaired renal function, the physician should consider withdrawal of lisinopril if the patient is currently taking it.
• Assessment of renal function is crucial in patients with hypertension, heart failure, or myocardial infarction.
• Dosage reduction and/or discontinuation of the diuretic and/or lisinopril may be required in patients with pre-existing renal impairment.
• Patients with acute myocardial infarction should be initiated with caution on lisinopril if they have evidence of renal dysfunction, defined as serum creatinine concentration exceeding 2 mg/dL 2.
• The GISSI-3 trial showed that patients with acute myocardial infarction treated with lisinopril had a higher incidence of renal dysfunction in-hospital and at six weeks 2.

From the Research

Elevated Creatinine Levels: Next Steps

Elevated creatinine levels confirmed 6 weeks apart indicate impaired renal function, which requires prompt attention and management. The following steps can be taken:

• Referral to a Nephrologist: Earlier referral to a nephrologist is expected to lead to better health care outcomes and lower costs for both the patients and the health care system 3.
• Investigations: All patients with newly discovered renal insufficiency must undergo investigations to determine the potential reversibility of disease, to evaluate the prognosis, and to optimize planning of care 3.
• Monitoring: Patients with an established, progressive increase in serum creatinine level should be followed by a nephrologist, and adequate preparation for dialysis or transplantation requires at least 12 months of relatively frequent contact with a renal care team 3.
• Cardiovascular Risk Reduction: Optimal management of chronic kidney disease (CKD) includes cardiovascular risk reduction, treatment of albuminuria, avoidance of potential nephrotoxins, and adjustments to drug dosing 4.
• Ultrasound Imaging: Ultrasound imaging is a key investigatory step in the evaluation of CKD and can help assess both structural and functional aspects of kidneys 5.

Key Considerations

When managing elevated creatinine levels, it is essential to consider the following:

• Interpretation of Serum Creatinine Results: Interpretation of serum creatinine results is not always easy, and analytical limitations, such as reference intervals, standardization, and analytical interferences, must be taken into account 6.
• Systematic Approach: A systematic approach to finding the underlying cause of an elevated creatinine level is crucial, including history, physical examination, baseline tests, and complementary blood tests and imaging studies 7.
• Staging and Risk Assessment: Staging and new risk assessment tools that incorporate glomerular filtration rate and albuminuria can help guide treatment, monitoring, and referral strategies 4.