An observational study in Diabetic Nepheopathy, sponsored by Assiut University. Not yet recruiting. Open to participants aged 8 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-08.
Sponsored by Assiut University · Observational
Diabetes mellitus (DM) is a globally prevalent metabolic disorder with an escalating burden on renal health. Diabetic kidney disease (DKD) represents the leading cause of end-stage renal disease (ESRD) worldwide, affecting approximately 20-40% of all diabetic patients . The pathophysiology of DKD involves progressive microvascular injury characterized by glomerular hyperfiltration, mesangial expansion, tubular damage, and ultimately interstitial fibrosis, culminating in irreversible loss of renal function . Despite advances in management, a substantial subset of diabetic patients develop significant renal structural damage while remaining normoalbuminuric, rendering conventional biomarkers such as urinary albumin-to-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR) inadequate for early detection .
Conventional renal screening relies heavily on serum creatinine and albuminuria thresholds; however, these markers reflect filtration loss that occurs only after considerable parenchymal injury has already taken place . Novel tubular biomarkers such as neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) have shown promise in detecting early tubular damage, yet their routine clinical applicability remains limited by cost and lack of standardized thresholds . Renal biopsy, the gold standard for histological staging of DKD, is invasive, carries hemorrhagic risk, and is entirely impractical as a population-level screening tool .
Renal Duplex Doppler ultrasonography has emerged as a valuable, safe, non-invasive modality for assessing intrarenal hemodynamics. The Renal Resistive Index (RRI), calculated as (Peak Systolic Velocity - End Diastolic Velocity) / Peak Systolic Velocity, and the Pulsatility Index (PI), defined as (Peak Systolic Velocity - End Diastolic Velocity) / Mean Velocity, reflect downstream microvascular impedance and arteriolosclerosis . Elevated RRI values have been independently associated with progressive renal functional decline, systemic arterial stiffness, and adverse cardiovascular outcomes across multiple patient populations .
In the context of Type 2 Diabetes Mellitus (T2DM), elevated RRI has been consistently demonstrated to correlate with disease duration, poor glycemic control, microalbuminuria, and declining eGFR, with a diagnostic cut-off of approximately 0.65-0.70 proposed in several studies . Mahmoud et al. (2023) demonstrated that diabetic patients exhibited significantly higher mean RRI values compared to healthy controls, underscoring the utility of intrarenal Doppler indices in detecting early nephropathy before overt albuminuria manifests . In Type 1 Diabetes Mellitus (T1DM), particularly in pediatric and young adult cohorts, RRI has been shown to rise in parallel with glycemic variability and tubular injury markers, preceding the onset of microalbuminuria by years .
The relationship between RRI and systemic microvascular complications such as retinopathy and neuropathy has also been explored, with evidence suggesting that elevated RRI may serve as a surrogate marker of global microvascular disease burden in diabetic patients . Furthermore, dynamic RRI assessment following physiological stimulation has demonstrated predictive value for long-term renal outcome in both T2DM and hypertensive patients . The prognostic significance of RRI extends beyond renal function, with studies reporting its independent association with major adverse cardiovascular events and all-cause mortality in chronic kidney disease populations .
Despite this accumulating evidence, a critical gap remains: the vast majority of published studies have examined T1DM and T2DM populations independently, under heterogeneous Doppler acquisition protocols and with varying patient selection criteria. No adequately powered, three-arm comparative study has simultaneously evaluated RRI and PI across T1DM, T2DM, and matched healthy controls under a single, rigorously standardized protocol. Furthermore, data specific to the Egyptian population, which carries one of the highest global burdens of adult diabetes and diabetic nephropathy, are remarkably scarce. This study is therefore designed to address this methodological gap by conducting a structured comparative cross-sectional analysis of RRI and PI across all three groups, with comprehensive correlation to clinical, glycemic, and renal parameters, to establish locally validated diagnostic thresholds and advance the role of renal duplex sonography as a frontline early screening tool for diabetic renal microvascular disease.
A. Clinical and Demographic Assessment
A structured data collection sheet will be completed for each participant by the enrolling physician prior to the Doppler examination, covering the following domains:
(i) Demographic data: Full name (coded for anonymity), age, sex, residence (urban/rural), educational level.
(ii) Anthropometric measurements: Height (cm) via calibrated stadiometer; weight (kg) via calibrated digital scale; Body Mass Index (BMI) = weight(kg)/height²(m²); waist circumference (cm) at the umbilical level.
(iii) Blood pressure: Measured in the right arm after 5 minutes of seated rest using a standardized sphygmomanometer (mean of two readings taken 5 minutes apart). Hypertension defined as SBP ≥140 mmHg and/or DBP ≥90 mmHg, or current antihypertensive therapy.
(iv) Diabetes history: Type (T1DM/T2DM), date of diagnosis, total disease duration (years), current antidiabetic treatment regimen (insulin type/regimen, oral hypoglycemic agents), history of hypoglycemic episodes, and self-monitoring practice.
(v) Complication screening: Diabetic retinopathy assessed by dilated fundoscopy performed within the preceding 12 months (classified as: none, non-proliferative, or proliferative). Diabetic peripheral neuropathy assessed clinically using the Michigan Neuropathy Screening Instrument (MNSI) including foot inspection and vibration/monofilament testing, confirmed by nerve conduction studies where available.
(vi) Current medications: Antihypertensives (ACE inhibitors, ARBs, calcium channel blockers, diuretics), statins, aspirin, and any potentially nephrotoxic agents.
B. Laboratory Investigations Venous blood samples and mid-stream urine specimens will be collected from all participants on the morning of the Doppler examination following a minimum 8-hour overnight fast. All analyses will be performed at the Central Clinical Laboratory, Assiut University Hospital, using standardized validated methods.
(i) Glycemic Parameters: Fasting blood glucose (FBG) by enzymatic hexokinase method (mg/dL); Glycated hemoglobin (HbA1c) by high-performance liquid chromatography (HPLC) method (%). Poor glycemic control defined as HbA1c ≥8% per ADA 2023 guidelines.
(ii) Renal Function Parameters: Serum creatinine (mg/dL) by Jaffe kinetic method (IDMS-traceable); Blood urea nitrogen (BUN, mg/dL) by urease-glutamate dehydrogenase method; estimated GFR (eGFR) calculated using the CKD-EPI 2021 creatinine equation (mL/min/1.73 m²); serum uric acid by uricase-peroxidase method; serum electrolytes (sodium, potassium, bicarbonate).
(iii) Albuminuria Assessment: Spot urinary albumin-to-creatinine ratio (UACR) from a first-morning void mid-stream urine specimen. Urinary albumin by immunoturbidimetry; urinary creatinine by Jaffe method. UACR expressed as mg/g creatinine. Classification: normoalbuminuria (\<30 mg/g), microalbuminuria (30-300 mg/g), macroalbuminuria (>300 mg/g). Two separate UACR measurements on two different occasions required to confirm persistent albuminuria.
(iv) Lipid Profile: Total cholesterol, LDL-cholesterol (Friedewald equation if TG\<400 mg/dL), HDL-cholesterol, and triglycerides (mg/dL) by standardized enzymatic colorimetric methods.
(v) Complete Blood Count (CBC): Hemoglobin, white blood cell count, and platelet count by automated hematology analyzer.
C. Renal Duplex Doppler Ultrasound Protocol (i) Equipment: All examinations will be performed using a high-resolution ultrasound machine (GE LOGIQ E10 or equivalent) equipped with a curved-array transducer operating at 3.5-5 MHz, with colour flow Doppler and pulsed-wave Doppler capabilities.
(ii) Patient Preparation and Positioning: Minimum 6-8 hours fasting prior to examination to reduce bowel gas and ensure adequate renal visualization. Patients void prior to the examination. Participants initially placed in supine position, with subsequent transition to lateral decubitus (flank approach) for optimal renal windows. Both kidneys assessed systematically in all participants.
(iii) B-Mode Morphological Assessment (Pre-Doppler): Before Doppler sampling, the following B-mode parameters are recorded for each kidney: renal length (cm) on the longitudinal axis; anteroposterior (AP) diameter and width (cm); cortical thickness (cm) at mid-pole; cortical echogenicity graded relative to the adjacent liver/spleen; corticomedullary differentiation (preserved or lost); presence of renal stones, cysts, or focal lesions; assessment of renal pelvis for hydronephrosis.
(iv) Colour Flow Doppler Assessment: Colour Doppler is first applied to identify the main renal artery, segmental arteries, interlobar arteries, and arcuate arteries. Colour gain and scale (PRF) are adjusted to optimally display low-velocity intrarenal flow without aliasing. Filter setting is set to the lowest level to capture low-velocity signals in arcuate vessels.
(v) Pulsed-Wave Doppler Sampling and Index Calculations: The sample volume gate (1.5-3 mm) is placed over the interlobar arteries at the corticomedullary junction (primary sampling site) and arcuate arteries as the secondary site. Three separate arterial waveform measurements are obtained from each of the upper, mid, and lower poles of each kidney. Doppler angle is maintained at \<60° (ideally ≤30°). At least three clean, reproducible waveforms are accepted per sampling site. The ultrasound machine software automatically calculates: Peak Systolic Velocity (PSV, cm/s); End Diastolic Velocity (EDV, cm/s); Renal Resistive Index (RRI) = (PSV - EDV) / PSV (normal range 0.55-0.70); Pulsatility Index (PI) = (PSV - EDV) / Mean Velocity. The final RRI and PI for each participant is the mean of all nine readings from each kidney, then averaged across both kidneys.
(vi) Quality Control Measures: All Doppler examinations will be performed by a single experienced radiologist (the principal investigator, under direct supervision of the supervising professors) to minimize inter-observer variability. All measurements will be re-reviewed by the supervising radiologist in a blinded fashion for quality assurance. Any examination deemed technically inadequate (Doppler angle>60°, poor waveform quality, motion artefact) will be repeated within 48 hours.
Assiut University is the lead sponsor of 4,916 studies on the registry; 2,113 are open to participants now.
Of its 13 completed or terminated interventional studies of FDA-regulated products, 0 (0%) have results posted.
Counted across the registry records on this site, refreshed daily.
All gender patients with minimum age of 8 years old
Inclusion criteria
1- known non_diabetic renal parenchymal disease 2-single functioning kidney 3- severe uncontrolled hypertension 4- any cardiac conditions
Difference in renal resistive index (RRI) and pulsatility index (PI) measured by renal Doppler ultrasonography among patients with T1DM, patients with T2DM, and matched non-diabetic controls.
Time frame: Baseline
1-Correlation of RRI and PI with Clinical and Laboratory Parameters 2-Association of RRI and PI with Diabetic Microvascular Complications 3-Diagnostic Performance of RRI and PI in T1DM and T2DM
Time frame: Baseline
No study locations are listed for this record.
Plan to share: Undecided
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Assiut University