RISK OF CONTRAST-INDUCED NEPHROPATHY AMONG DIABETIC PATIENTS UNDERGOING FUNDUS FLUORESCEIN ANGIOGRAPHY - A PROSPECTIVE STUDY

Introduction:

The risk of contrast-induced nephropathy (CIN) with iodinated contrast media is well recognized. However, there is limited literature about the risk of acute kidney injury (AKI) following use of non-iodinated contrast like fluorescein which is used in fundus fluorescein angiography (FA). Since FA is often used in patients with diabetic retinopathy who may have concomitant diabetic nephropathy (DN), there is a concern whether fluorescein usage can deteriorate the kidney function. Therefore, we aimed to study the incidence and risk factors of CIN in diabetic patients undergoing FA.  

Methods:

A prospective, observational, single-center study of diabetic patients undergoing FA was conducted from July 2021 to August 2023. Baseline serum creatinine (sCr), and urinary NGAL (uNGAL) were done just before FA. Estimated glomerular filtration rate (eGFR) was calculated using Chronic Kidney Disease Epidemiology Collaboration equation. Patients received 2.5 mL of 20% solution of sodium fluorescein dye (500 mg) intravenously for FA. CIN was defined as ≥ 0.3 mg/dL increase in sCr within 2 days or ≥50% increase in sCr within 7 days after FA. sCr was repeated once at 48 to 72 hours after FA. Patients were stratified based on the presence of DN, baseline sCr [low-risk (sCr < 1.5 mg/dL), intermediate-risk (sCr 1.5- 2.0 mg/dL) and high-risk groups (sCr >2.0 mg/dL)], and baseline eGFR [normal eGFR (≥60 mL/min/1.73 m2), intermediate eGFR (30-59 mL/min/1.73 m2) and low eGFR groups (≤29 mL/min/1.73 m2)]. uNGAL was repeated within 4 hours of study, and >25% increase from baseline was considered as AKI. Demographics and co-morbidities were also analyzed to investigate any association with CIN.  

Results:

A total of 146 patients undergoing FA were studied. Of these, 71% were males and the mean age was 56.3 ± 10.1 years. CIN after FA was seen in 7 (4.79%) patients. No significant change was seen pre- and post-FA in mean sCr levels and eGFR (Table 1). Proportion of patients who developed CIN was significantly higher in sCr-based intermediate-risk (2.78%) and high-risk groups (12%) (p =0.007). eGFR risk category, degree of albuminuria or presence of DN had no association with CIN. uNGAL was done for 131 patients. Median uNGAL was significantly higher post-FA (Table 1). Sixty-six (50.38%) patients had ≥ 25% rise in uNGAL from the baseline. Multivariate analysis revealed no independent risk factors for CIN.

Conclusions:

In our study, fluorescein dye administration was not associated with an increased risk of CIN using traditional creatinine-based criteria. However, half of the study patients had >25% rise in level of novel biomarker uNGAL which could indicate development of subclinical AKI after FA. The clinical significance of rise in early sensitive biomarker post FA needs to be evaluated further in larger prospective studies with sufficient follow-up.

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.