HEROIC: a 5-year observational cohort study aimed at identifying novel factors that drive diabetic kidney disease: rationale and study protocol

INTRODUCTION

Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease worldwide and a major cause of premature mortality in diabetes mellitus (DM). While improvements in care have reduced the incidence of kidney disease among those with DM, the increasing prevalence of DM means that the number of patients worldwide with DKD is increasing. Improved understanding of the biology of DKD and identification of novel therapeutic targets may lead to new treatments. A major challenge to progress has been the heterogeneity of the DKD phenotype and renal progression. To investigate the heterogeneity of DKD we have set up The East and North London Diabetes Cohort (HEROIC) Study, a secondary care-based, multiethnic observational study of patients with biopsy-proven DKD. Our primary objective is to identify histological features of DKD associated with kidney endpoints in a cohort of patients diagnosed with type 1 and type 2 DM, proteinuria and kidney impairment.

METHODS AND ANALYSIS

HEROIC is a longitudinal observational study that aims to recruit 500 patients with DKD at high-risk of renal and cardiovascular events. Demographic, clinical and laboratory data will be collected and assessed annually for 5 years. Renal biopsy tissue will be collected and archived at recruitment. Blood and urine samples will be collected at baseline and during annual follow-up visits. Measured glomerular filtration rate (GFR), echocardiography, retinal optical coherence tomography angiography and kidney and cardiac MRI will be performed at baseline and twice more during follow-up. The study is 90% powered to detect an association between key histological and imaging parameters and a composite of death, renal replacement therapy or a 30% decline in estimated GFR.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Bloomsbury Research Ethics Committee (REC 18-LO-1921). Any patient identifiable data will be stored on a password-protected National Health Services N3 network with full audit trail. Anonymised imaging data will be stored in a ISO27001-certificated data warehouse.Results will be reported through peer-reviewed manuscripts and conferences and disseminated to participants, patients and the public using web-based and social media engagement tools as well as through public events.

Evaluation of iris and iridociliary body lesions with anterior segment optical coherence tomography versus ultrasound B-scan

Aims

To compare anterior segment optical coherence tomography (AS-OCT) with ultrasound B-scan (USB) in evaluating iris and iridociliary body lesions.

Methods

Image features and resolution comparison between AS-OCT and USB in 126 patients (126 eyes) presenting with iris or iridociliary body lesion. Bland–Altman plots were generated to assess the level of agreement between the two techniques.

Results

The three most common diagnoses were iris naevi (62 (49.2%)), iris pigment epithelial cysts (23 (18.3%)) and iris melanoma (11 (8.7%)). Image feature comparison for USB was better than AS-OCT in visualising all tumour margins (81 (64.3%) vs 59 (46.8%)), posterior tumour margin (54 (42.9%) vs 16 (12.7%)) and producing less posterior shadowing (121 (96%) vs 43 (34.1%)). Image resolution comparison revealed USB to be slightly better for resolving the overall tumour (45 (35.7%) vs 43 (34.1%)) and posterior tumour surface (70 (55.6%) vs 32 (25.4%)) but AS-OCT was better for resolving the anterior (62 (49.2%) vs 4 (3.2%)) and lateral tumour surface (62 (49.2%) vs 31 (24.6%)). Comparing the three most common diagnoses, USB was better for visualising iris pigment epithelial cysts (12 (52.2%) vs 2 (8.7%)) and iris melanoma (7 (63.6%) vs 1 (9.1%)) but AS-OCT was better (28 (45.2%) vs 15 (24.2%)) for visualising iris naevi. Bland–Altman plots showed good agreement between the two techniques for lesions smaller than 3 mm in base and 2 mm in elevation.

Conclusions

AS-OCT is superior to USB for imaging small lesions pertaining to the anterior iris but USB is better for imaging larger iris lesions with posterior or ciliary body extension.