Diagnostic Accuracy of Urine Microalbumin and Serum Uric Acid: A Case-control Study of Patients with Preeclampsia in the Komfo Anokye Teaching Hospital, Kumasi, Ghana

Abstract

Background: There is increasing prevalence of preeclampsia coupled with the need to identify and institutionalize more sensitive diagnostic tools for preeclampsia. This study evaluated the diagnostic accuracy of urine microalbumin and serum uric acid as early markers of preeclampsia among Ghanaian women attending antenatal care at the Komfo Anokye Teaching Hospital (KATH). Methods: A case-control study was conducted among pregnant women at the Obstetrics and Gynaecology (O&G) department of the KATH, Kumasi-Ghana from October 2011 to May 2012. One hundred and twenty-three (123) participants were recruited for this study after written informed consent was obtained. Socio-demographic characteristics, medical history and previous obstetric history was obtained through medical records of the eligible participants. Blood pressure and anthropometrics were measured according to standard procedure; urine samples were collected for estimation of spot urine protein and microalbuminuria; and venous blood sample was taken for biochemical analysis and platelet count. Results: A significant positive linear correlation was observed between spot urine protein and urine microalbumin (r=0.324, p=0.006). A negative linear correlation was observed between uric acid and spot urine micro albumin (r=0.033, p=0.786). A urinary micro albumin value of 75.45 mg/g was identified as the best threshold to detect a spot urine protein of > +2 with a sensitivity of 92.7% and a specificity of 80.0%, PPV of 81.03% and NPV of 33.3%. Area under the curve = 0.835; asymptomatic p-value of 0.0001 at 95% CI (0.678-0.991). In contrast, serum uric acid level of 263.5 mg/g was identified as the best cut-off point to detect a spot urine protein of > +2 with sensitivity and specificity of 89.1% and 33.3% respectively (PPV of 77.2% and NPV) of 20.8%. Area under the curve = 0.552; asymptotic p-value of 0.538 at 95% CI (0.364-0.740). Conclusion: Urine levels of microalbumin, as a measure of proteinuria are elevated in preeclamptics and can be used in place of spot macro protein estimation to diagnose preeclampsia especially in the early stages.