Adding Empagliflozin to Liraglutide Did Not Improve Kidney Function in Advanced Diabetic Kidney Disease

Adding empagliflozin to liraglutide did not improve eGFR (primary outcome), urinary protein excretion, or glycemic control over 6 months. Empagliflozin significantly increased hemoglobin (12.9→13.7 g/dL, p<0.05) and decreased body weight (66.1→64.5 kg, p<0.05). No significant differences in blood pressure, lipids, or HbA1c.

Open-label RCT, 41 patients randomized 1:1. Liraglutide 0.3-0.9 mg/day subcutaneous. Empagliflozin 10 mg daily oral added at 6 months in treatment group. Primary outcome: eGFR change during months 6-12. Secondary outcomes: body weight, blood pressure, hemoglobin, lipids, glucose, HbA1c, urine protein/creatinine ratio.

Both GLP-1 RAs and SGLT2 inhibitors have shown kidney benefits individually. Clinicians increasingly combine these drugs, but evidence for their combined benefit in advanced kidney disease is lacking. This negative result suggests that in advanced-stage disease, the combination may not offer additive kidney protection over GLP-1 RA alone.

This is one of the first RCTs examining the combination of GLP-1 RA and SGLT2 inhibitor specifically for kidney outcomes in advanced diabetic nephropathy. The negative result is important — it suggests a ceiling effect or that advanced kidney disease may not respond to combination therapy the way earlier-stage disease does.

Very small sample (41 patients). Open-label design introduces bias. Short 6-month combination period may be insufficient to detect kidney benefit. Japanese population with liraglutide dosing (max 0.9 mg) lower than Western standards (1.8 mg). Advanced kidney disease may have limited reversibility.