(451) Urinary calcium to creatinine ratio for the prediction of preeclampsia: a systematic review and meta-analysis

Objective: To assess the diagnostic accuracy of the urinary calcium-to-creatinine ratio as an early predictor of preeclampsia in pregnant patients without pre-existing hypertensive disorders.

Study Design: We conducted a systematic search of several electronic databases from inception to March 31, 2023, to identify pertinent studies assessing the diagnostic accuracy of the urinary calcium-to-creatinine ratio. These studies involved pregnant patients who were at risk for preeclampsia but were not diagnosed with the condition at the time of their participation in the study. We compiled combined measures of diagnostic accuracy, including diagnostic odds ratios, sensitivity, specificity, likelihood ratios, and hierarchical summary receiver-operating characteristic plots, to compare the performance of the calcium-to-creatinine ratio.

Results:

The meta-analysis included 33 studies, totaling 6,454 patients. The urinary calcium-to-creatinine ratio demonstrated a combined sensitivity of 69% (95% CI: 0.60-0.76) and a specificity of 94% (95% CI: 0.92-0.96) for the prediction of preeclampsia. The positive likelihood ratio was 12.3, and the negative likelihood ratio was 0.33, resulting in a diagnostic odds ratio of 37. Subgroup analysis of 23 studies using a common cut-off value of < 0.04 showed enhanced sensitivity (75%, 95% CI: 0.67-0.82) and specificity (96%, 95% CI: 0.95-0.97). The hierarchical summary receiver-operating characteristic curve indicated superior overall test accuracy, with an area under the curve of 0.91 (95% CI: 0.88-0.93) for all studies and 0.97 (95% CI: 0.95-0.98) for studies that employed a urinary calcium-to-creatinine cut-off value of < 0.04.

Conclusion: The urinary calcium-to-creatinine ratio is a useful screening tool for the early prediction of preeclampsia in pregnant patients without any underlying hypertensive disorders. It displays high sensitivity and specificity, offering the potential to improve clinical decision-making and fast-track the management of preeclampsia, leading to enhanced maternal and neonatal outcomes.