Spot Urine Protein-to-Creatinine Ratio Compared with Dipstick Proteinuria as a Primary Screening Tool for Renal Disease in a Community Setting

The Kidney Disease: Improving Global Outcomes (KDIGO) advocates the use of dipstick proteinuria as a primary screening tool. However, the performance of dipstick urinary for proteinuria has been adjudged to be weak, unreliable with poor predictive value. This study aimed to determine and compare significant proteinuria (SP) using spot urinary protein-to-creatinine ratio (UPr/UCr) as a primary screening tools with dipstick proteinuria among the high-risk African children. This study was a cross-sectional study, involving 33 schools in Ogbomoso land, Southwestern Nigeria. A total of 1316 apparently healthy children were recruited through a multistage sampling technique from both rural and urban communities using a semi-structured questionnaire. Dipstick urinalysis was performed on early morning urine samples. Urinary protein was determined using a turbidimetric method, while Jaffe's reaction was used to measure urinary creatinine concentration. Statistical analysis was performed using IBM SPSS Statistics version 23.0 for Windows. The prevalence of SP using spot UPr/UCr (>= 0.2) and dipstick proteinuria (>= 1+) was 18.0% and 0.8%, respectively (P < 0.001). Of the 224 subjects with SP using UPr/UCr, the females (140; 20.1%) had higher proportion of SP compared to males (84; 15.4% - P = 0.032). Nephrotic range proteinuria was detected in 9/10 (90%) using UPr/UCr, while urinary dipstick method identified only 3/10 (30%). A biserial correlation coefficient (r = 0.092; P =0.001) and inter-rater agreement (Cohen's Kappa = 0.01) were poor and McNemar's test was P < 0.0001. In the community, UPr/UCr ratio appeared to perform better than dipstick as a primary screening tool for renal disease and may be adopted in the early detection of SP as a marker of kidney disease against the current KDIGO guideline of dipstick proteinuria.