An international study of variation in attitudes to kidney biopsy practice

Background:
A kidney biopsy is an essential investigation for diagnosis but is invasive and associated with complications. Delaying or missing the opportunity to diagnose kidney disease could result in adverse patient outcomes. This study aimed to examine attitudes to kidney biopsy across the world.

Methods:
An online questionnaire for nephrologists was designed based on the existing literature with input from patients. Anonymized data was collected on individual and institutional demographics, indications and contraindications for biopsy, and attitudes and barriers to access. A propensity-to-biopsy score was generated from responses which allowed clinicians to compare their practice with international colleagues. A higher score was associated with an increased likelihood of recommending biopsy. The questionnaire was disseminated through international nephrology societies including the National Kidney Foundation and by social media.

Results:
Participants responding to the questionnaire included 1181 clinicians from 83 countries, making it the largest international study in this area to date. The propensity-to-biopsy scores were significantly different between the thirteen countries with over twenty clinicians participating (P<0.001) and was highest in Mexico and lowest in the Philippines.

Kidney biopsy was most often recommended in cases with higher proteinuria levels and most often avoided in patients with small kidneys. An adjusted linear regression model demonstrated that a significantly higher propensity-to-biopsy score was found in males, younger clinicians, frequent performers of kidney biopsy, increased job seniority and larger institution size (P=0.05).

Conclusions:
Kidney biopsy practice is varied internationally and is subject to human and systemic factors. Further research is required to understand the variances behind clinical decision making.