Endocrine and metabolic · Hard
This case is fictional and exists for study. It describes no real patient.
62 years · male
A 62-year-old male presents for his annual diabetic review. He has a 10-year history of type 2 diabetes mellitus and suffered an acute myocardial infarction two years ago. He feels mildly fatigued but denies polyuria, polydipsia, or recent weight loss. His current medications include metformin 1000 mg twice daily, gliclazide 160 mg twice daily, ramipril 10 mg daily, aspirin 75 mg daily, and atorvastatin 80 mg daily. Physical examination reveals a BMI of 31 kg/m² and blood pressure of 134/82 mmHg. Chest is clear on auscultation, with normal heart sounds and no peripheral oedema.
Vital signs
- HR
- 72 bpm
- BP
- 134/82 mmHg
- RR
- 14/min
- Temp
- 36.6 °C
- SpO₂
- 98%
Examination findings
- BMI 31 kg/m²
- Normal heart sounds S1 and S2 with no murmurs
- No pedal oedema
Investigations
| HbA1c | 68 mmol/mol | reference: 20-42 |
| eGFR | 42 mL/min/1.73m² | reference: >90 |
| Serum creatinine | 145 µmol/L | reference: 60-110 |
| Serum potassium | 4.6 mmol/L | reference: 3.5-5.0 |
| ALT | 28 U/L | reference: 10-40 |
Question 1 of 3
Which of the following is the most appropriate add-on therapy to optimize this patient's glycaemic control and cardiovascular outcomes according to NICE guidelines?
According to UK NICE NG28 guidelines, for patients with type 2 diabetes mellitus and established cardiovascular disease (such as a previous myocardial infarction), an SGLT2 inhibitor with proven cardiovascular benefit (e.g., empagliflozin or dapagliflozin) should be added to metformin regardless of target HbA1c attainment. Option D (linagliptin) is a DPP-4 inhibitor that provides glycaemic lowering but lacks the proven cardiorenal risk reduction of SGLT2 inhibitors. Option A (liraglutide) is a GLP-1 receptor agonist that can be used if SGLT2 inhibitors are contraindicated, not tolerated, or if further glycaemic or weight reduction targets are needed, but SGLT2 inhibitors are prioritized for cardiorenal protection in dual/triple therapy. Option C (basal insulin) is unnecessary at this stage before utilizing targeted oral or injectable therapies with cardiorenal benefit.
Teaching point: NICE guidelines mandate adding an SGLT2 inhibitor with proven cardiovascular benefit for patients with type 2 diabetes and established cardiovascular disease.
Question 2 of 3
Regarding his current metformin regimen and an eGFR of 42 mL/min/1.73m², which of the following is the most appropriate action?
Metformin is renally cleared and poses an increased risk of lactic acidosis as renal function declines. Guidelines recommend reviewing and reducing the dose of metformin if eGFR falls below 45 mL/min/1.73m² (maximum total daily dose of 1000 mg, e.g., 500 mg twice daily). Metformin should only be completely discontinued if the eGFR falls below 30 mL/min/1.73m². Option C carries an elevated risk of lactic acidosis. Option D is premature because the patient's eGFR is still above 30 mL/min/1.73m². Option B does not address the overall daily dose reduction required for impaired excretion.
Teaching point: Reduce the maximum daily dose of metformin to 1000 mg daily when eGFR is 30–45 mL/min/1.73m², and stop it if eGFR falls below 30 mL/min/1.73m².
Question 3 of 3
Which of the following is the most appropriate next investigation to further stage and evaluate this patient's diabetic kidney disease?
Evaluating diabetic kidney disease (DKD) requires assessment of both renal function (eGFR) and quantitative protein excretion. A spot urinary albumin-to-creatinine ratio (ACR) on a morning urine sample is the initial and standard method to detect and monitor microalbuminuria/proteinuria. Option C (renal ultrasound) is indicated for rapid GFR decline, macroscopic haematuria, or suspected urinary tract obstruction, but not routine DKD evaluation. Option D (24-hour collection) is cumbersome, prone to collection errors, and obsolete compared to spot ACR testing. Option B (cystatin C) is not recommended for routine DKD staging in general primary care.
Teaching point: Annual evaluation of diabetic kidney disease requires measuring both eGFR and urinary albumin-to-creatinine ratio (ACR).
Key learning points
- Patients with type 2 diabetes and established cardiovascular disease should receive an SGLT2 inhibitor with cardiorenal benefit alongside metformin.
- Metformin dose must be reduced to a maximum of 1000 mg/day when eGFR drops between 30 and 45 mL/min/1.73m² and stopped if eGFR is <30 mL/min/1.73m².
- Diabetic kidney disease screening and monitoring require both estimated glomerular filtration rate (eGFR) and spot urinary albumin-to-creatinine ratio (ACR).
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