Protein creatinine index: A possible predictor of nephropathy in hypertensives, in Northern India

Abstract

Background: >33% of the hypertensive Indians develops nephropathy. Proteinuria is an early indicator of nephropathy. Gold standard for determining proteinuria is 24-hour urinary protein excretion which is a troublesome task with poor patient compliance. Protein creatinine index (PCI) in a random urine sample has been advocated by some researchers as an alternative approach. Aim of this study was to evaluate the association of PCI with the severity and duration of hypertension, in North Indian population.

Methods: 120 Stage-1 hypertensives, 120 stage-2 hypertensives, 40 pre-hypertensives and 40 normotensives were included in this study. 240 Hypertensive subjects were divided into 3 sub-groups based on duration: <5years (n=80), 5-10years (n=80) and >10years (n=80). Urinary protein was estimated by sulfosalicylic acid method and urinary creatinine was measured using modified Jaffe's method. PCI was measured as described by Shaw et al. Data was statistically analyzed by ANOVA and Pearson's correlation test using SPSS v20.

Results: PCI of stage-2 hypertensives (157.83±51.53) was significantly higher than normo-, pre- and stage-1 hypertensives. PCI of stage-1 hypertensives (134.15±46.04) was significantly higher than normotensives only. PCI of hypertensives for 5-10years (137.29±49.55) and >10years (181.85±47.42) was significant higher than controls and pre-hypertensives. PCI showed significantly stronger association with severity (r=0.595) and duration (r=0.745) of hypertension as compared to urinary protein and creatinine concentration. Data also suggest that the risk of renal injuries against the backdrop of raised blood pressure (BP) increases after 5years of hypertension.

Conclusion: PCI can be used as a screening tool for early detection of hypertensive nephropathy. PCI monitoring should be incorporated in the routine checkup module of patients suffering from hypertension for >5years.

Keywords: Hypertension; Hypertensive nephropathy; Protein creatinine index; Proteinuria.