Abstract
Background and Aims
Chronic kidney disease (CKD) is a global healthcare problem associated with several comorbid conditions including, cardiovascular disease, and diabetes, all of which are strong risk factors for the development of significant cognitive impairment. We recently reported the baseline outcomes of our older adult cohort with mild to moderate CKD (stages 3-4) and diabetes, where 48% were found to have a cognitive impairment ranging from mild to severe symptoms. [1] This study reports the outcomes at 36-months post baseline of the prevalence and incidence of cognitive impairment in this cohort the patients who at baseline were considered to have normal cognitive function.
Method
Cognitive function was assessed in patients over aged 55 years, with an estimated glomerular filtration rate < 45ml/min/1.73m 2, attending a renal and diabetes outpatient clinic, at baseline and at 36-months. The diagnosis of cognitive impairment was based upon patient and informant interview, case note review, neuropsychological assessment and application of Diagnostic and Statistical Manual of Mental disorders version 5 (DSM-5) and Petersen’s criteria for mild cognitive impairment (MCI). The incidence of cognitive impairment was calculated by dividing the number of new cases during study follow-up, by the person-time at risk throughout the observation period. Since it is not possible to precisely determine when a person actually develops cognitive impairment between baseline and follow-up, the midpoint of time between having normal cognition and becoming a case is assumed.
Results
Ninety-two patients without cognitive impairment at baseline, were included in this investigation (mean age of 75.8 + 9.1; 49 males: 43 female). Upon neuropsychological assessment and the application of DSM-5 criteria at follow-up, it was revealed that 25/92 (27%) of the cohort had developed a cognitive impairment ranging from MCI (n=19), to major symptoms (n = 6). The crude prevalence for MCI was 20.6%, and for dementia it was 6.5%. The total person years in the study were 237.38 years, with an overall incidence rate of 10.53 (95% Confidence interval 6.82-15.55) per 100 person-years.
Conclusion
This longitudinal cohort investigation reports the prevalence and incidence of new cases of cognitive impairment ranging from MCI to dementia in CKD. The crude prevalence in the current investigation for the development of cognitive impairment was 27%. The overall incidence rate for new cases of NCD was just over 10%. In other words, for every 100 patients in our current investigation we would estimate that around 10 will develop some a cognitive impairment ranging from MCI to dementia per year. Our findings from this and our previous investigation suggest that a significant number of CKD patients are at risk for the development of significant neurodegenerative conditions and in view of this cognitive function should be screened and monitored routinely in clinical practice. This will assist with appropriate health service planning, service development, clinical interventions and the assessment of the effectiveness of new and existing treatments services.
Cognitive Impairment in Chronic Kidney Disease-Prevalence, Mechanisms and Consequences