What is the significance of a 55-year-old male with prediabetes having impaired renal function, as indicated by elevated creatinine levels and microalbumin/creatinine ratio?

From the Guidelines

The patient's laboratory values indicate normal kidney function with no evidence of microalbuminuria, and I recommend continuing regular monitoring of kidney function with annual microalbumin-to-creatinine ratio testing, maintaining good glycemic control to prevent progression to diabetes, and following lifestyle modifications including a balanced diet, regular exercise, and weight management if needed. The microalbumin-to-creatinine ratio has remained consistently below 30 mg/g creatinine (specifically <5, <8, and <7) over the past year, which is within normal limits 1. While the urine creatinine has increased from 71.4 mg/dL to 139.7 mg/dL, this variation is not clinically concerning as the microalbumin levels remain low (<7.0 mg/L). According to the American Diabetes Association, annual diabetic kidney disease screening should be performed via urine albumin–creatinine ratio on a spot urine sample and eGFR in patients with comorbid hypertension or diabetes 1.

Some key points to consider in the management of this patient include:

• The importance of early detection of microalbuminuria as it can be the first sign of diabetic nephropathy 1
• The use of ACE inhibitors or ARBs to slow the progression of kidney disease in hypertensive patients with diabetes with an eGFR less than 60 mL/min/1.73 m2 and a urine albumin–creatinine ratio greater than 300 mg/g 1
• The recommendation for referral to a nephrologist when there is uncertainty about the cause of kidney disease or advanced kidney disease 1
• The importance of maintaining good glycemic control to prevent progression to diabetes and following lifestyle modifications including a balanced diet, regular exercise, and weight management if needed 1

Overall, the patient's kidneys appear to be functioning normally at present, and with continued monitoring and lifestyle modifications, the risk of developing diabetic kidney disease can be minimized.

From the FDA Drug Label

Metformin hydrochloride tablets are contraindicated in patients with an eGFR less than 30 mL/min/1.73 m 2[see Contraindications ( 4) ]. Initiation of metformin hydrochloride tablets is not recommended in patients with eGFR between 30 to 45 mL/min/1. 73 m 2.

The patient's eGFR is not provided, but based on the creatinine levels, we can estimate the eGFR.

• Creatinine, Urine mg/dL: 139.7 (1 day ago), 85.3 (1 year ago), 71.4 (1 year ago) However, the eGFR cannot be calculated with the provided information. To determine if metformin is contraindicated, an eGFR should be calculated. Key points:
• Renal function should be assessed before initiating metformin.
• Metformin is contraindicated in patients with eGFR < 30 mL/min/1.73 m^2.
• Initiation of metformin is not recommended in patients with eGFR between 30-45 mL/min/1.73 m^2. Since the eGFR is not provided and cannot be calculated, no conclusion can be drawn regarding the use of metformin in this patient. 2

From the Research

Prediabetes and Associated Risks

• Prediabetes is an intermediate stage between normal glucose regulation and diabetes, affecting 1 in 3 adults in the US and approximately 720 million individuals worldwide 3.
• It is defined by a fasting glucose level of 100 to 125 mg/dL, a glucose level of 140 to 199 mg/dL measured 2 hours after a 75-g oral glucose load, or glycated hemoglobin level (HbA1C) of 5.7% to 6.4% or 6.0% to 6.4% 3.
• Prediabetes is associated with increased risk of diabetes, cardiovascular events, and mortality, with approximately 10% of people with prediabetes progressing to having diabetes each year in the US 3.

Management of Prediabetes

• First-line therapy for prediabetes is lifestyle modification that includes weight loss and exercise or metformin, with lifestyle modification associated with a larger benefit than metformin 3.
• Intensive lifestyle modification has been shown to decrease the incidence of diabetes by 6.2 cases per 100 person-years during a 3-year period, while metformin decreased the risk of diabetes among individuals with prediabetes by 3.2 cases per 100 person-years during 3 years 3.
• Many studies have shown that lifestyle modification and metformin are effective in preventing the development of type 2 diabetes, although lifestyle modification seems to have a more sustainable effect 4.

Kidney Disease Risk

• Prediabetes is modestly associated with an increase in chronic kidney disease risk, with a summary relative risk of chronic kidney disease of 1.12 (95% CI 1.02-1.21) in a meta-analysis of 9 cohort studies 5.
• Chronic kidney disease screening among people with prediabetes, and aggressive management of prediabetes in those with chronic kidney disease may be warranted 5.
• The provided lab results show an increase in creatinine and microalbumin levels over time, which may indicate an increased risk of kidney disease 5.

Lab Results

• The provided lab results show the following values:
  • Creatinine, Urine: 139.7 mg/dL (1 day ago), 85.3 mg/dL (1 year ago), 71.4 mg/dL (1 year ago)
  • Microalb, Ur: <7.0 mg/L (1 day ago), <7.0 mg/L (1 year ago), <5.0 mg/L (1 year ago)
  • Microalb/Creat Ratio: <5 mg/g creat (1 day ago), <8 mg/g creat (1 year ago), <7 mg/g creat (1 year ago)
• These results should be interpreted in the context of the individual's overall health and medical history, and may indicate an increased risk of kidney disease or other complications associated with prediabetes 5.