Background: Constant high blood pressure leads to changes in the blood vessels of the kidneys, which can reduce blood flow and cause gradual kidney damage. The Renal Resistive Index (RRI), measured through Doppler ultrasound, is a safe and non-invasive method that shows the resistance of blood flow in the kidney vessels. It can help detect early signs of kidney problems before serious damage occurs. This study aimed to assess RRI in adults with clinically diagnosed hypertension and to compare the results with those of healthy individuals.

Materials and methods: Prospective experimental study was conducted among 201 participants, which comprises of hypertensive adults (experimental group) and 100 normotensive (healthy) as the control group. Renal Doppler ultrasound was performed using standard procedures to measure RRI from the interlobar arteries of both kidneys. Both descriptive and inferential statistical tools were used for data analysis and level of significance was set at p < 0.05.

Results: The mean age, height, weight and body mass index, were 48.8 years, 170.4cm 75.2kg and 25.78kg/m² respectively. The mean Systolic BP, Diastolic BP, Left kidney RI and Right kidney RI were 148.8 ± 25.7mmHg, 92.3 ± 18.5mmHg, 0.68 ± 0.07 and 0.67 ± 0.07 respectively for the participants, The mean age for hypertensive subject was 53.4 ± 12.9 years while that of normotensives was 44.2 ± 15.6 years, the mean height for hypertensive subjects was 170.2 ± 8.7cm while that of the normotensives was 170.6 ± 8.6cm. The average RRI values were found to be significantly higher in hypertensive patients than in the normotensive group (p < 0.001).

Conclusion: Hypertension increases renal vascular resistance, suggesting early changes in kidney function even before visible signs of disease appear. Measuring RRI using Doppler ultrasound is a simple, reliable, and non-invasive method that can be used to detect, evaluate, and monitor kidney changes in hypertensive patients.