eGFR dips with added thiazide in heart failure were not linked to worse outcomes

Design

Secondary analysis of a randomised controlled trial (CLOROTIC)

Population

About 220 patients admitted with acute decompensated heart failure

Primary outcome

Mortality by early eGFR change

Effect

eGFR −14.4% (thiazide) vs 0% at day 4; mortality HR per 30% decline 0.86 (0.48–1.55)

CLOROTIC randomised patients admitted with acute decompensated heart failure to hydrochlorothiazide or placebo on top of loop diuretics. This secondary analysis examined whether early eGFR falls, at day 2 (225 patients) and day 4 (218 patients), predicted death or heart failure readmission over about three months.

Median eGFR fell 9.7% at day 2 and 14.4% at day 4 with thiazide, against essentially no change with placebo. Yet the eGFR decline was not associated with mortality in either arm (HR per 30% decline 0.86–0.96 with thiazide), nor with the composite outcome.

This supports the view that a creatinine rise during effective decongestion often reflects haemodynamic change rather than kidney injury. Stopping diuresis because creatinine rises can leave patients congested, which is itself harmful. The numbers were small, so a modest association cannot be excluded.

• Expect eGFR to dip when a thiazide is added to loop diuretics during decongestion.
• Do not stop effective decongestion solely because creatinine rises modestly.
• Judge diuretic response by weight, urine output, congestion and electrolytes, not creatinine alone.
• Watch potassium and sodium closely with combination diuretics.

Why it matters

Fear of rising creatinine often halts diuresis before patients are decongested.

Don't overread it

With about 220 patients and three months' follow-up, the analysis cannot rule out a small harm from larger falls.

The statistics, in plain English

An HR near 1 with wide intervals (for example 0.48 to 1.55) means no association was seen, but the data are compatible with modest benefit or harm.

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