Role of cystatin C in the detection of sight-threatening diabetic retinopathy in Asian Indians with type 2 diabetes.

AIM: To study the association between cystatin C and sight-threatening diabetic retinopathy (STDR) in Asian Indians with type 2 diabetes (T2DM). METHODS: In a cross-sectional study carried out at two tertiary centres in India in 2022, individuals with T2DM underwent clinical and ophthalmic assessments and estimation of serum cystatin C. Grading of DR was done by retina specialists. STDR was defined by the presence of severe non-proliferative DR (NPDR), proliferative DR (PDR) and/or diabetic macular edema. Receiver operating characteristic (ROC) curves were used to identify cystatin C cut-off value for detecting STDR. RESULTS: Among 420 individuals with T2DM (mean age 56 ± 9 years; mean duration of diabetes 14.5 ± 7.9 years), 121 (24.1 %) had No-DR, 119 (28.3 %) had No-STDR and 200 (49.6 %) had STDR. Mean cystatin C level was significantly higher in individuals with STDR compared to those with no-STDR and No-DR (1.34 vs 1.06 vs 0.93 mg/L, p < 0.001). Cystatin C cut-off value ≥1.11 mg/L had a C statistic of 0.944 (95 % CI: 0.909-0.968, p < 0.001), 96.8 % sensitivity and 78.2 % specificity for detection of STDR. CONCLUSION: Elevated serum cystatin C was strongly associated with STDR and could possibly be used as a biomarker for screening for sight-threatening diabetic retinopathy.

Predominant peripheral lesions in patients with diabetic retinopathy and its association with systemic comorbidities.

Purpose: To determine the associations of predominant peripheral lesions (PPLs) with systemic comorbidities in individuals with diabetic retinopathy. Methods: This is a multicenter cross-sectional observational study conducted across three tertiary eye care centers in south India between January 2019 and July 2021. Ultra-widefield fundus images of consecutive patients with varying severity of diabetic retinopathy with data on systemic comorbidities were classified based on the presence or absence of PPL. Systemic comorbidities (hypertension, diabetic kidney disease, coronary artery disease, dyslipidemia, and anemia) were compared between the two groups. Results: A total of 879 participants (70.1% males) were included in the study, of which 443 (50.4%) patients had PPL. The mean age of the study participants was 56 ± 10 years, mean age of onset of diabetes was 41.24 ± 11.6 years, and mean duration of diabetes was 15.39 ± 7.6 years. The number of PPL increased with increasing severity of DR. Of all the systemic comorbidities analyzed, we found that coronary artery disease (CAD) had a significant association with PPL (Odds ratio [OR]-1.69; 95% confidence interval [CI], 1.12-2.55; P = 0.013) after adjusting for diabetic retinopathy severity, duration of diabetes, and age of onset of diabetes. Conclusion: The presence of PPL is a marker for coronary artery disease and early referral to cardiology is warranted.