Proteinuria level tracks latency and maternal complications in preterm pre-eclampsia

Design

Secondary analysis of two randomised trials, single centre (South Africa)

Population

291 women with pre-eclampsia diagnosed at 26 to 32 weeks, managed expectantly

Primary outcome

Pregnancy latency and composite adverse maternal or perinatal outcomes

Effect

Median latency 15.3, 10.0 and 4.9 days; maternal complications 8.8%, 16.1% and 27.9% across proteinuria bands

A secondary analysis of two randomised trials from Cape Town included 291 women with pre-eclampsia diagnosed between 26 and 32 weeks and managed expectantly. Women were grouped by 24-hour proteinuria.

Median prolongation of pregnancy was 15.3 days with under 3 g, 10.0 days with 3 to 5 g and 4.9 days with 5 g or more. Maternal complications occurred in 8.8%, 16.1% and 27.9% respectively. There was no association with composite perinatal outcomes. Proteinuria predicted latency a little less well than the sFlt-1/PlGF ratio (AUC 0.67 vs 0.78) and maternal outcomes about as well (0.64 vs 0.67). Both predicted perinatal outcomes poorly.

The finding supports using the protein level as a prognostic aid where angiogenic tests are not available. It is a secondary analysis, so it generates a hypothesis rather than a management rule.

• Quantify proteinuria (24-hour or protein-creatinine ratio) when pre-eclampsia is managed expectantly before 32 weeks.
• Expect shorter latency and more maternal complications at 5 g/24 h or more.
• Do not use the protein level alone to predict perinatal outcome.
• Where sFlt-1/PlGF is unavailable, proteinuria gives broadly similar prognostic information for maternal outcomes.
• Delivery timing should still follow maternal and fetal status, not a protein threshold.

Why it matters

A cheap, universally available measurement carries prognostic information that resembles a costly biomarker.

Don't overread it

A secondary analysis of trial data shows association; it does not show that acting on proteinuria improves outcomes.

The statistics, in plain English

An AUC of 0.5 is chance and 1.0 is perfect. Values of 0.64 to 0.78 show modest discrimination, useful for context but not for deciding an individual woman's course. The analysis was not a test of a strategy.

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