Abstract
Background and Aims
Cognitive impairment is correlated with increased mortality of chronic kidney disease patients and hypertension is a well known comorbidity. While transplantation offers various general health and cognitive function improvement over dialysis, kidney transplant recipients (KTRs) still show greater cognitive impairment than healthy control. Researched pathophysiological mechanisms in KTR population include infection and immunosuppressive induced neurotoxicity. The aim of this study was to determine what impact do body composition, dietary habits and muscular strength have on cognitive impairment of hypertensive KTRs.
Method
48 (52.17 %) men and 44 (47.83%) women, aged 59.7 (range25-83) years were included. For each patient data about duration after Ktx, duration of dialysis before Ktx, age, gender, body weight and height were collected and BMI and waist-to-height ratio (WHtR) were calculated. Tanita MC780 Multi Frequency segmental body composition analyser was used to measure content of body fat, muscle mass, and visceral fat each study subject measured in kilograms (kg) and percentage (%.) Peripheral muscle strength of KtR was measured by using a standardized handgrip dynamometry protocol. The Mini Mental State Exam (MMSE) was used as an indicator of cognitive impairment. Mediterranean Diet Serving Score (MDSS) questionnaire was used to determine adherence to Mediterranean Diet (MeDi) considering the consumption of foods and food groups per meal, day or week.
Results
Out of 92 KTR patients with hypertension, 5 of them scored ≤ 24 points on MMSE scale implying serious cognitive dysfunction. Mean score of MMSE was 28.2, (range 22-30) Regarding MDSS score, 11 patients scored ≥ 16 meaning highest adherence, while 67 KTRs scored < 16 meaning low adherence to MeDi, (results range 2-18) . Positive correlations were found between MMSE score (higher score meaning better cognitive functioning) and MDSS score ( higher score implying better adherence to MeDi)( R=0,282, p=0,012), consuming 1-2 portions of fruits( R=0,266,p=0,016) or ≥ 2 portions of vegetables ( R=0,241,p=0,03) per main meal, skeletal muscle mass (%) (R=0,278, p=0,008), peripheral muscular strength( R=0,325,p=0,003) and fat free mass (kg)(R=0,212,p=0,045). On the other hand we found statistically significant negative correlation between MMSE score and WHtR ( R=-0,255, p= 0,023) . as well as PWV(R=-0,244, p=0,022).
Conclusion
Cognitive impairment correlations in this study are similar to ones in general population specially regarding Mediterrranean diet and muscle mass . Possible explanation of positive MeDi impact on cognitive function in KTRs could be its low phosphate intake which prevents vascular calcification and negative effects of hyperparatiroidism. Although benefits of MeDi in CKD patients can be argued due to high pottasium levels, after kidney Tx it should not be an obstacle anymore. These results suggest that lifestyle interventions such as following MeDi, building more muscle and reducing fat could provide hypertensive KTR patients with longer preservation of cognitive function.
Low skeletal muscle mass is associated with mortality in kidney transplant recipients