How often should renal function be assessed in patients with ADPKD, and what specific tests are recommended?

In patients with autosomal dominant polycystic kidney disease (ADPKD), renal function should be assessed regularly from age 18 onwards, with the frequency tailored to the individual's estimated glomerular filtration rate (eGFR), albumin:creatinine ratio (ACR), rate of disease progression, and other risk factors. The UK guidelines recommend using eGFR and ACR monitoring frequencies as outlined in chronic kidney disease (CKD) management, adjusting for the underlying cause such as ADPKD, and the rate of decline in renal function ¹,²,⁵.

Specifically, eGFR and ACR should be measured at least annually in patients with mild to moderate CKD (GFR categories G1-G2) and more frequently in those with more advanced CKD (G3a to G5), with monitoring frequency increasing with worsening eGFR and higher ACR categories. For example, patients with G3a CKD should have at least one eGFR and ACR check per year, while those with G4 or G5 CKD require monitoring 2 to 4 times per year depending on albuminuria severity ¹,⁵.

Monitoring should be intensified if there is evidence of accelerated progression, defined as a sustained decrease in eGFR of 25% or more and a change in CKD category within 12 months, or a sustained decrease in eGFR of 15 mL/min/1.73 m2 per year ¹,⁵. In such cases, further investigations including renal tract ultrasound are recommended to assess structural changes typical of ADPKD, such as cyst burden and kidney size, which are important for disease staging and management ¹,⁵[(Wołyniec et al., 2008)].

The specific tests recommended for renal function assessment in ADPKD include serum creatinine to calculate eGFR, urine albumin:creatinine ratio (ACR) to detect proteinuria, and renal ultrasound imaging to evaluate cystic changes and kidney morphology ¹,⁵[(Wołyniec et al., 2008)]. Additionally, a full blood count (FBC) should be arranged in patients with CKD stage G3 or worse to exclude renal anaemia ¹,⁵.

Overall, the frequency and scope of renal function assessment in ADPKD should be individualized based on disease severity, progression rate, and patient factors, with shared decision-making involving the patient. Regular monitoring allows timely identification of progression and complications, facilitating appropriate specialist referral and management ¹,⁵.