A 45-year-old man is evaluated during a new patient visit. He immigrated to the United States from Serbia 4 years ago and was diagnosed with Balkan endemic nephropathy at that time. His kidney function has remained stable, and his only symptoms are mild nocturia and urinary frequency. Medical history is otherwise unremarkable. He takes no medications.

On physical examination, temperature is 37.1 °C (98.7 °F), blood pressure is 138/82 mm Hg, pulse rate is 76/min, and respiration rate is 12/min. BMI is 26. The remainder of the examination is normal.

Laboratory studies:

Hemoglobin

9.6 g/dL (96 g/L)

Electrolytes

Normal

Creatinine

1.7 mg/dL (150.1 µmol/L)

Glucose

Normal

Estimated glomerular filtration rate

35 mL/min/1.73 m2

Urinalysis

Specific gravity 1.005; 2+ glucose; 10-20 erythrocytes/hpf

An increased risk of which of the following is most likely in this patient?