The impact of the combination of kidney and physical function on cognitive decline over 2 years in older adults with pre-dialysis chronic kidney disease
No longitudinal study has investigated the impact of combination of kidney function (KF) and physical function (PF) on cognitive decline in these patients.
We conducted a 2-year prospective cohort study enrolling 131 patients ≥ 65 years with pre-dialysis chronic kidney disease (CKD). We assessed cognitive function with the Japanese version of the Montreal Cognitive Assessment (MoCA-J). We calculated %MoCA-J based on the rate of change between baseline and follow-up MoCA-J scores, and defined cognitive decline over 2 years as a %MoCA-J of less than the first quartile value. We defined eGFR ≥ 30 as mild-to-moderate and eGFR < 30 mL/min per 1.73 m2 as severe. In addition, low PF was defined as low handgrip strength (< 26 for men and < 18 kgf for women) and/or low gait speed (< 0.8 m/s). Patients were classified into four groups: group 1, patients with mild-to-moderate impairment in KF and high PF; group 2, with mild-to-moderate impairment in KF and low PF; group 3, with severe impairment in KF and high PF; and group 4, with severe impairment in KF and low PF.
Eighty-four patients completed follow-up assessment. Multivariate logistic regression analysis showed that the combination of severe impairment in KF and low PF was significantly associated with cognitive decline (odds ratio 5.73). However, no significant cognitive decline was observed in patients with either severe impairment in KF or low PF alone.
We may need to focus on maintaining PF in older patients with advanced CKD may help to prevent cognitive decline.
KeywordsChronic kidney disease (CKD) Cognitive decline Kidney function Physical function
The authors are grateful to Ms. M. Nakanome and Ms. Y. Sawamura for their contributions to the assessment of patient management in this study, and to Mr. S. Koyama, Mr. S. Ohji, Mr. T. Tanaka, Mr. A. Sato, Mr. N. Tani, Mr. Y. Kimura, and Mr. M. Yamada for their insightful advice on earlier drafts of this manuscript.
Compliance with ethical standards
Conflict of interest
All authors have no conflicts of interest to disclose.
All procedures performed in studies involving human participants were in accordance with ethical standards of the institutional and national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The study protocol was reviewed and approved by the Institutional Committee on Human Research of St. Marianna University School of Medicine (IRB approval no. 2691).
Informed consent was obtained from all individual participants included in this study.
- 3.Foley RN, Parfrey PS, Sarnak MJ. Epidemiology of cardiovascular disease in chronic renal disease. J Am Soc Nephrol. 1998;9(12 Suppl):16–23.Google Scholar
- 14.National Kidney Foundation. K/DOQI clinical practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Am J Kidney Dis. 2002;39(2 Suppl 1):1–266.Google Scholar
- 16.KDIGO 2012 clinical practice guideline for the evaluation and management of chronic kidney disease: Definition and classification of CKD. Kidney Int Suppl. 2011;3(1):19–62Google Scholar
- 20.Mahoney FI, Barthel DW. Functional evaluation: the Barthel Index. Md State Med J. 1965;14:61–5.Google Scholar