Sex- and Stage-Specific Predictors of Anemia in Chronic Kidney Disease: A Retrospective Cohort Study

Background: Anemia is a common complication of chronic kidney disease (CKD), yet no study has explored differences in anemia risk factors based on disease severity and gender. Therefore, this study investigates potential differences in anemia risk among individuals with varied kidney disease severities and sexes. Methods: This multicenter, longitudinal cohort study was conducted using data (2008-2016) from the Epidemiology and Risk Factors Surveillance of CKD database. This database was associated with Taiwan's National Health Insurance Research Database (for the 2008-2019 period). To identify predictive risk factors for anemia, we developed a subset multivariate logistic model using stepwise variable selection. Additionally, 10-fold cross-validation was conducted to facilitate model selection and internal validation. Results: Of the 5656 patients with CKD, 519 (9.18%) with anemia and 5137 (90.82%) without. After adjusting for age, sex, and serum creatinine, stepwise logistic regression analysis identified the main independent predictive factors for anemia in CKD patients. Notably, "Receive low sodium diet education" (OR: 0.66, 95% CI: 0.446-0.975), "DBP (mmHg)" (OR: 0.98, 95% CI: 0.965-0.999), "Gout" (OR: 1.86, 95% CI: 1.175-2.937), and "Congestive heart failure" (OR: 1.85, 95% CI: 1.131-3.028) was significantly associated with the presence of anemia among CKD patients. Conclusions: This study identifies gout and cardiovascular disease as important correlates of anemia in patients with CKD. Moreover, it reveals an inverse association between elevated diastolic blood pressure and receiving education on a low-sodium diet with the occurrence of anemia.