Calciuria and preeclampsia: a case-control study

Aim: Calciuria has been reported to decrease in preeclampsia. We compared calciuria among groups of normal, hypertensive and preeclamptic pregnant women, and assessed its correlation with the severity of the disease.

Material and methods: We conducted a case-control study of mild and severe preeclampsia, chronic hypertension, and normal pregnancy, with 14 patients in each group. The groups were analyzed by one-way anova (variance analysis) for symmetrical distribution and Kruskal-Wallis test for asymmetrical distribution when comparing quantitative variables, and by crossed tables when comparing qualitative variables.

Results: There were statistically significant differences between the groups when comparing severe preeclampsia with chronic hypertension, and severe preeclampsia with the control group (P < 0.0001). The calciuria medians were 81.5 mg/24 h for severe preeclampsia, 118 mg/24 h for mild preeclampsia, 226 mg/24 h for chronic hypertension, and 272 mg/24 h for the control group. In a ROC (receiver operating characteristic) curve analysis, the best cutoff point for preeclampsia diagnosis was 167 mg/24 h, with a sensitivity of 75% and a specificity of 85%. The outcomes were more severe as the level of calciuria dropped.

Conclusion: Measurement of calciuria can differentiate between severe preeclampsia and chronic hypertension, and hypocalciuria is also a marker for disease severity.