Mini-Mental State Examination predicts mortality in patients on chronic hemodialysis

Background: No available and easy to administer cognitive test has been evaluated for the prediction of mortality in prevalent patients on chronic hemodialysis. The aim of the present study was to determine if the Mini-Mental State Examination (MMSE) was predictor of mortality in patients on chronic hemodialysis. Methods: One hundred twenty-seven prevalent patients on chronic hemodialysis were studied. All patients underwent assessment of cognitive function through the MMSE. The MMSE was administered during a midweek hemodialysis session, avoiding the beginning and the end of each treatment to minimize the effects of fluctuations in uremic syndrome or blood pressure in accordance with a previous study. An MMSE score ≤23 was used as indicative of cognitive impairment. Demographic, clinical, and laboratory parameters were recorded for each patient. Results: Mean (SD) MMSE was 23.2 ± 4.1. Median MMSE was 24 (min–max: 2–30). MMSE was ≤23 in 72 patients and >23 in 55. With data updated in March 2021, after a mean follow-up of 58.8 ± 41 months (range: 2–156 months), 75 patients died, and 17 were transplanted. None was lost to follow-up or was transferred to another unit. Dead participants, as compared with alive ones, were significantly older, had a higher Charlson Index score, had lower Activities daily living and Instrumental activities daily living, and had a lower MMSE score and lower serum albumin levels. Kaplan–Meier analysis showed that survival was significantly lower in patients with MMSE ≤23 than in those with MMSE >23 (log-rank χ2: 8.825, p = 0.003). According to Cox regression analysis, mortality was associated with age and inversely associated with MMSE. Conclusion: We show that the MMSE predicts mortality in prevalent patients on chronic hemodialysis.