Urine albumin-creatinine ratio may help predict Pre-clinical preeclampsia, finds Study
Pre-eclampsia (PE) is defined as a pregnancy-specific syndrome of reduced organ perfusion secondary to vasospasm and endothelial dysfunction. It is the second highest cause of maternal mortality, accounting for 12- 18% of deaths linked to pregnancy. Pre-eclampsia is diagnosed when the blood pressure is at or above 140/90 mmHg occurring on two occasions at least 6 h apart, associated with proteinuria greater than 300 mg / 24h after 20 weeks of gestation.
It appears to involve the systemic activation and injury of maternal endothelial cells, manifested by elevated blood pressure (BP), proteinuria, systemic inflammatory response, and the accumulation of antiangiogenic factors that appear to cause the disease by depriving essential growth factors of the glomerular endothelial cells. Permeability of the glomerular basement membrane to proteins, including albumin, is key to the diagnosis. While 24-hour urine collection is the gold standard for urinary albumin excretion quantification, it is tedious and the diagnosis results in delay of at least 24 hours.
A research was carried out by Pallavi Mahajan and Jyochnamayee Panda to evaluate the spot urinary albumin creatinine ratio (ACR) assessed in asymptomatic pregnant women between 20-28 weeks of gestation to predict preeclampsia.
This hospital based prospective, observational study was conducted with 150 patients to establish whether a spot urine albumin-creatinine ratio measured between 20-28 weeks gestation could predict pre-eclampsia in asymptomatic pregnant woman in Department of Obstetrics and Gynecology, Kalinga Institute of Medical Sciences and PBM Hospital, Bhubaneswar between September 2018 and April 2020.
At each visit, their blood pressure was assessed and all signs and symptoms of pre-eclampsia were evaluated. Urine ACR estimation was done by collecting spot mid stream urine sample and subjecting it to immunoturbidimetric microalbumin method for albumin and modified Jaffe's method for creatinine estimation.
In this prospective observational study of 150 patients, 28(18.7%) patients developed preeclampsia. Majority of the patients who developed preeclampsia were in the age group of 21-25 years (46.5%).
As per the distribution of the patients according to BMI, mean BMI of unaffected and preeclampsia patients were 24.62 ± 3.06kg/m2 and 24.78 ± 2.45kg/m2 respectively. As per the parity, incidence of preeclampsia was slightly higher in primigravida 16(57.2%) than multigravida 12(42.8%).
The mean urine albumin-creatinine ratio (UACR) value of unaffected patients was significantly lower compared to preeclampsia patients. The UACR cut off value was taken as 35.5mg/mmol as in the earlier study. The number of patients according to test positivity and negativity is 18.7% and 81.3% respectively.
Association of UACR with preeclampsia was seen out of 28 (18.7%) patients that were UACR positive, 25 (89.3%) patients developed preeclampsia and 3 (2.4%) patients remained unaffected, whereas among 122 (81.3%) patients that were UACR negative 3 (10.7%) patients developed preeclampsia. The sensitivity and specificity of UACR were calculated at 89.29% and 97.54% respectively. The positive predictive value was 89.29% and the negative predictive value was 97.54%.
Typically, preeclampsia manifests in third trimester of pregnancy, but the underlying mechanisms start functioning as early as 8-18 weeks of pregnancy. Although preeclampsia is not preventable, it is possible to prevent deaths occurring due to this condition. Women who do not receive prenatal care are more likely to succumb to the complications related to preeclampsia-eclampsia than those women who received.
In this study, the incidence of preeclampsia was 18.7% and it was shown that ACR is significantly higher in patients with preeclampsia than those who are unaffected. In developing countries the identification of risk groups for preeclampsia through accessible and effective technology will lead to better maternal and fetal health outcomes as prenatal care will be initiated prior to the disease process being identified.
In near future, UACR could be very useful test not only for the prediction of development of preeclampsia, but also predict its magnitude and fetomaternal outcomes.
This study showed that UACR values were higher in preeclamptic womens and UACR > 35.5mg/mmol predicted preeclampsia well before the clinical manifestations occurred. It is a simple, fast and reliable tool for prediction of preeclampsia.
Source: Pallavi Mahajan1, Jyochnamayee Panda; Indian Journal of Obstetrics and Gynecology Research;