Don't let flat SGLT2-inhibitor surrogates undermine their use in diabetic CKD

Design

Systematic review and meta-analysis of 17 randomised trials

Population

29,192 patients with diabetic chronic kidney disease

Primary outcome

Renal surrogate markers (eGFR, albuminuria) and metabolic/safety outcomes

Effect

eGFR +0.25 (−0.08 to 0.57) and albuminuria neutral; HbA1c −0.40%; volume-depletion RR 1.36 (1.16–1.59)

A meta-analysis of 17 randomised trials (29,192 patients) examined SGLT2 inhibitors specifically in diabetic CKD. They improved the things you would expect — HbA1c (−0.40%), weight (−1.36 kg) and systolic blood pressure (−2.98 mmHg) — but had no significant short-term effect on the surrogate markers eGFR (mean difference +0.25 mL/min/1.73 m²) or albuminuria, and raised volume-depletion events (relative risk 1.36).

The risk is that a clinician seeing a patient's albuminuria or eGFR fail to improve on an SGLT2 inhibitor concludes the drug is not working and stops it. That would be a mistake. As the authors stress, these neutral surrogate findings sit against large outcome trials that show clear long-term cardiorenal protection — fewer kidney-failure events and deaths.

The practice point is to keep SGLT2 inhibitors foundational in diabetic CKD, judge them by the outcome-trial evidence rather than a patient's short-term surrogate numbers, and manage the real volume-depletion risk with sick-day rules rather than by stopping the drug. In India, where these agents are now affordable, the implementation gap — eligible patients not on one — matters more than the surrogate readings.

• SGLT2 inhibitors in diabetic CKD improved HbA1c, weight and blood pressure but not short-term eGFR or albuminuria.
• Do not stop an SGLT2 inhibitor because albuminuria or eGFR has not improved.
• Trust the outcome trials showing long-term cardiorenal protection over short-term surrogates.
• Manage the higher volume-depletion risk with sick-day rules, not discontinuation.

Why it matters

It guards against stopping a proven cardiorenal drug because its surrogate markers look flat in an individual.

Don't overread it

Neutral short-term surrogate effects do not mean SGLT2 inhibitors lack benefit — the long-term cardiorenal protection comes from dedicated outcome trials, not these markers.

The statistics, in plain English

A mean eGFR difference of +0.25 with an interval crossing zero is genuinely neutral, but surrogate markers over months need not track the hard outcomes measured over years, which is where the benefit was shown.

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