Table 1.

Eligible criteria based on PICOS.

	Inclusion criteria	Exclusion criteria
Participant	Patients with DKD diagnosed clinically or biopsy-proven DN	Patients receiving dialysis; patients with diabetes and other chronic kidney disease
Exposure	DKD/DN	–
Comparator	DKD vs. Non-DKD, including diabetes mellitus, non-diabetic kidney disease, and healthy controls	–
Outcomes	Gut microbial diversity and composition	Insufficient data for analysis; not high-throughput sequencing technology for detecting gut microbiome
Study design	Observational study	–

DKD, diabetic kidney disease; DN, diabetic nephropathy.