Non-invasive Diagnosis of Idiopathic Nephrotic Syndromes (DNI-SNI)

Non-invasive Diagnosis of Idiopathic Nephrotic Syndromes : DNI-SNI

Renal biopsy (RB) is the reference diagnostic procedure for Idiopathic Nephrotic Syndrome (INS). It is an invasive procedure, particularly risky during the acute phase of nephrotic syndrome when anticoagulation therapy is required.

By identifying serum antibodies that allow for the non-invasive diagnosis of the main differential diagnoses of INS, (Membranous Nephropathy), the development of a non-invasive diagnostic tool for INS could help reduce the morbidity associated with the invasive renal biopsy procedure, minimizing the risk of incorrect diagnosis. We developed a diagnostic score, the SNIT, from routine clinical and biological variables to allow INS diagnoses in patients for whom detection of blood antibodies of Membranous Nephropathy were negative. The main goal of this study is to validate this diagnosis score in a prospective study, to allow INS diagnosis without renal biopsy.

Study Overview

• Status: Recruiting
• Conditions: Idiopathic Nephrotic Syndrome (INS)

Detailed Description

Medical management will not be altered by the protocol, and patients will be treated according to the practices of each center.

The investigator will offer participation in the study to all eligible consecutive patients in their center. They will provide an information sheet and answer any questions the patient may have. After obtaining the patient's non-opposition, the following clinical and biological data will be collected:

(Age, sex, medical and surgical history, BMI at admission, systolic and diastolic blood pressure at admission, presence of lower limb edema, CBC, blood electrolyte levels, urea, creatinine, albumin levels, urinary electrolytes, proteinuria, albuminuria, urine culture, antinuclear antibodies, serum protein electrophoresis, serum protein immunofixation, complement fractions C3 and C4, lipid profile).

The SNIT calculation will be performed automatically in the CRF from the variables it comprises, but will not be visible to the investigator.

As part of patient care, patients will be followed up one month after inclusion. During this visit, the evolving biological data (creatinine, albumin levels, proteinuria, albuminuria) and the treatment administered will be collected from the patient's medical records.

The final diagnosis will be collected as soon as it is available (within a maximum of 4 months for the completion and reporting of the histopathological results). Histological data will be collected from the report of the pathologist who examined the renal biopsy (available in the medical record). (In the case of INS: presence or absence of segmental and focal hyalinosis lesions, percentage of fibrosis).

The objectives of this study will be :

1. Evaluate the diagnostic performance of SNIT compared to renal biopsy (reference examination) for the diagnosis of Idiopathic Nephrotic Syndrome (INS)
2. Evaluate the other diagnostic parameters of the SNIT test.
3. Evaluate the avoidable costs
4. Evaluate the theoretical risks of a misdiagnosis of INS (through diagnostic delay and its consequences, as well as the risk of unnecessary corticosteroid treatment).

Duration of participant involvement and study duration:

The inclusion period will be 24 months. The follow-up period for participants will be a maximum of 4 months (until the histological diagnosis is returned). Therefore, the total duration of the research will be a maximum of 28 months.

• Study Type: Observational
• Enrollment (Estimated): 265

Contacts and Locations

• Study Contact: Name: Alexandre LAHENS, Dr; Phone Number: +33 1 56 01 70 43; Email: alexandre.lahens@aphp.fr
• Study Contact Backup: Name: Jean-Jacques BOFFA, Pr; Phone Number: +33 1 56 01 60 29; Email: jean-jacques.boffa@aphp.fr

Study Locations

• France
  • Paris, France, 75020
    • Recruiting
    • Service de Néphrologie et Dialyses, Hôpital Tenon
    • Contact: Alexandre LAHENS, Dr; Phone Number: +33 1 56 01 70 43; Email: alexandre.lahens@aphp.fr
    • Contact: Jean-Jacques BOFFA, Pr; Phone Number: +33 1 56 01 60 29; Email: jean-jacques.boffa@aphp.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The diagnostic management of pediatric nephrotic syndrome is already covered by specific guidelines.

Therefore, the population of our study will consist of adults over 18 years of age presenting with a first episode of nephrotic syndrome, without detectable anti-PLA2r antibodies in the serum (since their presence indicates the diagnosis of MN), and for whom a renal biopsy is indicated and performed for diagnostic purposes

Description

Inclusion Criteria:

• Patients aged 18 years and older
• Hospitalized for a first episode of nephrotic syndrome (proteinuria greater than 3g/g and albumin level < 30g/L)
• Negative anti-PLA2r antibodies in the blood
• Requirement for a renal biopsy for diagnostic purposes

Exclusion Criteria:

• Patients with known lupus nephropathy (prior to the current episode)
• Patients with known IgA nephropathy (prior to the current episode)

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
The sensitivity and specificity of the SNIT score (threshold = 0.36) and their 95% confidence interval	4 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of biopsies avoided with the use of SNIT. Proportions of diagnostic errors. Negative and positive predictive values and likelihood ratios of SNIT.		4 months
Avoidable costs: costs of biopsies, impact on nephrology services.		4 months
Estimation of the number of hospitalization days with the use of SNIT, and comparison with the actual number of hospitalization days.	The theoretical number of hospitalization days with the use of SNIT (i.e., estimated from the CRH data, subtracting the days of hospitalization required for renal biopsy in the case of a positive test). Adverse effects of corticosteroid treatment: infections, edema syndrome, corticosteroid-induced diabetes, heart failure decompensation.	4 months

Collaborators and Investigators

• Sponsor: Assistance Publique - Hôpitaux de Paris
• Investigators: Principal Investigator: Alexandre LAHENS, Dr, Assistance Publique - Hôpitaux de Paris

Study record dates

Study Major Dates

• Study Start (Actual): April 15, 2025
• Primary Completion (Estimated): August 1, 2027
• Study Completion (Estimated): August 1, 2027

Study Registration Dates

• First Submitted: February 6, 2025
• First Submitted That Met QC Criteria: February 6, 2025
• First Posted (Actual): February 11, 2025

Study Record Updates

• Last Update Posted (Actual): August 14, 2025
• Last Update Submitted That Met QC Criteria: August 11, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Keywords: Kidney disease; Creatinine; Renal disease; Diagnostic score; Renal biopsy; DNI-SNI; Nephrotic Syndromes; Idiopathic Nephrotic Syndromes
• Additional Relevant MeSH Terms: Urogenital Diseases; Pathologic Processes; Male Urogenital Diseases; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Disease; Syndrome; Nephrotic Syndrome; Nephrosis; Nephrosis, Lipoid
• Other Study ID Numbers: APHP241612; 2024-A02829-38 (Other Identifier: IDRCB number)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No