Contrast-induced nephropathy (CIN) is an acute kidney injury manifests within 72 h post-administration of contrast media, excluding other kidney-damage etiologies. Despite the recognition of CIN, the complex interplay among high-risk factors remains poorly understood, and precision in the existing risk stratification models is lacking. This retrospective, observational cohort study included patients who underwent percutaneous coronary intervention (PCI) or computed tomography angiography (CTA) at four hospitals in Guangdong, China, between 2010 and 2018. Demographic and clinical characteristics of the patients of prognostic interest were collected. The main outcome was CIN occurrence. In total 12,376 patients were included in the final data analysis. Contrast media dosage was positively associated with CIN risk, with an adjusted odds ratio (OR) of 1.007 for each standard deviation increase in dosage. Doses above 140 ml significantly increased CIN risk (adjusted OR = 3.27). Notably, hypertensive and diabetic patients experienced greater risks at doses >
140 ml. Subgroup analyses underscored the importance of personalized dosage management. This study highlights the critical need for dosage management to mitigate CIN risk, particularly in high-risk patients. Individualized risk assessment and dose optimization strategies are essential to minimize the risk of CIN development and improve patient outcomes.