Frequency and Severity of Cognitive Impairment Across Stages of Chronic Kidney Disease: A Cross-Sectional Study from A Tertiary Nephrology Centre in Rajasthan, India

Abstract

Background: Chronic kidney disease (CKD) is increasingly recognized as a risk factor for cognitive impairment, which may affect treatment adherence, daily functioning, and quality of life. Cognitive dysfunction may begin in earlier CKD stages and worsen with disease progression, but data across the full CKD stage spectrum remain limited. Objective: To evaluate the prevalence and severity of cognitive impairment across CKD stages and to identify clinical factors associated with lower Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scores. Methods: This cross-sectional study included 138 adults with CKD stages 2-5, including patients on maintenance hemodialysis (HD), recruited from a tertiary nephrology center in Rajasthan over 18 months. All participants underwent clinical and laboratory evaluation, estimated glomerular filtrations rate (eGFR) estimation by the Modification of Diet in Renal Disease (MDRD) equation, and cognitive assessment using the MMSE and MoCA. Associations were examined using correlation analysis and univariate and multivariable linear regression. Results: Mean MMSE and MoCA scores declined progressively with worsening CKD stage and were lowest in dialysis-dependent stage 5 disease. Cognitive impairment was identified in 67.4% of patients by MMSE and 49.3% by MoCA. In unadjusted analyses, older age, higher systolic blood pressure, lower hemoglobin, lower eGFR, and higher blood urea, serum creatinine, phosphate, and potassium levels were associated with worse cognitive scores. In adjusted analyses, blood urea remained independently associated with lower MMSE and MoCA scores, while eGFR remained an adjusted correlate of cognitive performance. Conclusion: Cognitive impairment increases with CKD severity and is most pronounced in dialysis-dependent patients. Routine cognitive screening using brief tools such as MMSE and MoCA may help identify at-risk CKD patients.