Prevalence and prognostic value of baseline and post-treatment renal insufficiency in colorectal cancer patients: a large retrospective cohort study of 10,581 patients in Shanghai, China (2019-2023).

Background: Baseline renal insufficiency (RI) and post-treatment renal insufficiency (PTRI) are prevalent comorbidities in patients with colorectal cancer (CRC). However, the prevalence, risk factors, and prognostic significance of these conditions remain controversial. Methods: This is a retrospective cohort study, which included all CRC patients treated at Shanghai Changhai Hospital (2019-2023). Multivariate logistic and Cox survival analyses were used to explore risk factors and prognostic value of baseline RI and PTRI. Results: Among 10,581 CRC patients, the prevalence rates of RI-related parameters were: baseline RI (32.4%), hematuria (31.2%), elevated serum cystatin C (CysC) (17.4%), proteinuria (12.3%), elevated serum uric acid (8.7%), elevated serum creatinine (4.3%), elevated blood urea nitrogen (BUN) (3.5%), reduced estimated glomerular filtration rate (eGFR) (2.2%), chronic kidney disease (CKD) diagnosed by ultrasonography(1.5%), and self-reported CKD (1.1%). Approximately half of RI cases (47.2%) were attributed to hematuria, and other RI-related parameters were complementary to hematuria in revealing RI. Among the 2,132 (20.3%) patients with PTRI, 14.8, 8.3, 4.4, 3.9 and 0.2% exhibited a ≥ 25% alteration in BUN, CysC, creatinine, eGFR and UA, respectively. Age ≥ 65 years and concomitant cardiovascular disease were independent predictors of baseline RI; open surgery, intestinal ostomy, postoperative complications and chemoradiotherapy were independent predictors of PTRI. Both baseline RI and PTRI were independent predictors of disease-free survival and overall survival. Conclusion: These results demonstrate that comprehensive RI assessment (incorporating eGFR, hematuria, proteinuria, and other RI-related parameters) provides clinically actionable insights. Given the high prevalence (baseline RI 32.4%, PTRI 20.3%) and significant survival impacts, early screening of RI and preventive strategies are critical for high-risk CRC patients.