AN ASSESSMENT OF FACTORS INFLUENCING RESISTIVITY AND PULSATILITY INDICES IN DIABETES MELLITUS

Abstract

common complication of diabetes mellitus, accounting for more than 25% of all end stage renal diseases and is the third most common cause of ESRD in sub-Saharan Africa. It has been shown that assessment of renal Doppler indices such as Resistivity Index (RI) and Pulsatility Index (PI) are effective methods of assessing renal functional status thus complementing the use of laboratory values and other imaging modalities. In this study, we assessed the effects of age, sex, hypertension and disease duration on renal Doppler indices in diabetic subjects. Subjects and Methods: Eighty adult diabetic subjects were recruited consecutively along with 80 apparently healthy non-diabetic controls matched for age, sex and body mass index (BMI). They were taken through socio-demographic, clinical and laboratory evaluation to assess BMI, Blood Pressure, Glycated Haemoglobin, etc. Thereafter pulsed Doppler indices (RI and PI) of the right renal artery were obtained from the spectral waveform of the interlobar or arcuate arteries at 3 different regions (upper, middle and lower poles) and the mean values recorded during arrested respiration. Doppler evaluations were performed by one investigator who was blinded to the biochemical parameters obtained from all study subjects. Data was analysed using SPSS package version 17. Results: The mean RI and PI values were significantly higher in diabetic patients than in controls (RI of 0.72 ± 0.06 Vs 0.63 ± 0.06, P < 0.0001 ) and (PI of 1.36 ± 0.24 Vs 1.08 ± 0.20, P< 0.0001). There was a graded increase in the mean values of the RI and PI with advancing age in diabetics as well as in controls. Significant positive correlation was also noted between the subjects ages and the renal Doppler values (p <0.05). Duration of diabetes, as well as that of hypertension, had a significant impact on the Doppler indices (RI and PI) which progressively increased with increasing duration. Gender did not have any influence on the renal Doppler indices. Conclusion: Renal RI and PI were significantly higher in diabetics as compared to the control subjects. Age caused a significant increase in renal PI values in both the diabetic and control groups but only in the renal arterial RI values in the control group when the age grouping method was used. Hypertension and disease duration were also noted to significant increase in renal Doppler indices in the diabetic subjects.