Risk factors for diabetic retinopathy, diabetic macular edema, and sight-threatening diabetic retinopathy

To identify the risk factors for the development of diabetic retinopathy (DR), diabetic macular edema (DME), and sight threatening DR (STDR) based on a city-wide diabetes screening program. Diabetic patients were prospectively recruited between June 2016 and December 2022. All patients underwent dilated fundus photography centered on the disc and macula or macula spectral domain optical coherence tomography (SD-OCT) scan. Complete medical history was documented.Systematic examination, blood analysis, and urinalysis were performed. Multivariate logistic regression analysis adjusting for age and sex was conducted. Out of 7,274 diabetic patients, 6,840 had gradable images, among which 3,054 (42.0%) were graded as DR, 1153 (15.9%) as DME, and 1,500 (20.6%) as STDR. The factors associated with DR, DME, and STDR included younger age (odds ratio [OR]: 0.96, 0.97, and 0.96 respectively), lower BMI (OR: 0.97, 0.95, and 0.95 respectively), longer duration of diabetes (OR: 1.07, 1.03, and 1.05 respectively) and positive of urinary albumin (OR: 2.22, 2.56, and 2.88 respectively). Other associated factors included elevated blood urea nitrogen (OR: 1.22, 1.28, and 1.27 respectively), higher LDL-cholesterol, lower blood haemoglobin (OR: 0.98, 0.98, and 0.98), insulin intake, presence of diabetic foot pathologies and diabetic peripheral neuropathy. We also identified novel risk factors, including high serum potassium (OR: 1.37, 1.46, and 1.55 respectively), high serum sodium (OR: 1.02, 1.02, and 1.04 respectively). Better family income was a protective factor for DR, DME, and STDR. Alcohol consumption once a week was also identified as a protective factor for DR. This study revealed high serum sodium, high serum potassium, low blood haemoglobin, and the level of family income as novel associated factors for DR, which can help with DR monitoring and management.