Heavier proteinuria in pre-eclampsia marks higher later kidney risk

Design

Nationwide population-based cohort, Denmark 1998 to 2018, follow-up to 2021

Population

286,078 pregnancies of at least 20 weeks; 9,538 (3.3 percent) with pre-eclampsia

Primary outcome

10-year risk of hypertension, chronic kidney disease and cardiovascular disease by proteinuria level

Effect

Chronic kidney disease 5.1% (4.3 to 5.9) with moderate or severe vs 1.2% (0.9 to 1.6) with no or mild proteinuria

A nationwide Danish cohort followed 286,078 women who were pregnant between 1998 and 2018, of whom 9,538 (3.3 percent) developed pre-eclampsia, through 2021. Pre-eclampsia was associated with higher 10-year risks of hypertension, chronic kidney disease and cardiovascular disease. The new detail is what the urinary protein level adds.

With no or mild proteinuria, the 10-year chronic kidney disease risk was 1.2 percent; with moderate or severe proteinuria it was 5.1 percent. Hypertension risk rose from 11.9 to 16.0 percent across the same groups. Cardiovascular risk at 10 years was similar either way, at about 1.1 to 1.2 percent.

The message for follow-up is to stratify. Every woman who had pre-eclampsia warrants blood-pressure and cardiometabolic review, but the proteinuria level recorded at the time points to who carries the higher chronic kidney risk and may need closer renal surveillance.

• Nationwide cohort of 286,078 pregnancies; 3.3 percent developed pre-eclampsia.
• 10-year chronic kidney disease risk was 5.1 percent (95% CI 4.3 to 5.9) with moderate or severe proteinuria versus 1.2 percent (0.9 to 1.6) with no or mild proteinuria.
• 10-year hypertension risk was 16.0 percent versus 11.9 percent across the two proteinuria groups.
• Cardiovascular risk at 10 years was similar, about 1.1 to 1.2 percent, regardless of proteinuria level.
• Arrange blood-pressure and renal review after any pre-eclampsia; prioritise closer renal follow-up where proteinuria was heavy.

Why it matters

Pre-eclampsia follow-up is often one-size-fits-all, yet proteinuria severity separates who carries the higher chronic kidney risk.

Don't overread it

This was observational — the proteinuria level marks risk, it does not prove it causes the later disease.

The statistics, in plain English

The confidence intervals for kidney risk in the two proteinuria groups do not overlap, so the higher risk with heavier proteinuria is unlikely to be chance; this is an adjusted association from routine data, not proof of cause.

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