Impaired kidney function is associated with lower cognitive function in the elder general population. Results from the Good Aging in Skåne (GÅS) cohort study

Table 2 Results of the cognitive tests in relation to two groups based on eGFR

Cognitive test	Cognitive domain	Number of0020participants by eGFR		Test result by eGFR		Mean difference	95% CI of difference		P-value
Cognitive test	Cognitive domain	Number of0020participants by eGFR		Test result by eGFR		Mean difference	95% CI of difference		(2-tailed)
		eGFR < 60 mL/min/1.73 m²	eGFR ≥60 mL/min/1.73 m²	eGFR < 60 mL/min/1.73 m²	eGFR ≥60 mL/min/1.73 m²		Lower	Upper
MMSE	Global	778	1624	25.84 ± 3.08	27.34 ± 2.32	−1.5	− 1.74	−1.25	< 0.001
Digit span forward	Learning and memory	763	1616	5.95 ± 1.74	6.44 ± 1.86	−0.48	− 0.63	− 0.33	< 0.001
Free recall	Learning and memory	734	1595	5.77 ± 2.30	7.05 ± 2.35	− 1.28	− 1.48	− 1.07	< 0.001
Recognition	Learning and memory	711	1588	10.85 ± 3.49	11.88 ± 2.81	−1.03	− 1.32	− 0.74	< 0.001
Word fluency	Language	765	1611	10.73 ± 4.58	12.51 ± 4.93	−1.77	−2.18	− 1.37	< 0.001
Digit cancellation	Complex attention	711	1608	14.56 ± 4.17	17.75 ± 4.01	−3.18	−3.54	−2.83	< 0.001
Pattern comparison	Complex attention	692	1598	21.33 ± 7.20	28.22 ± 7.36	−6.9	−7.55	−6.25	< 0.001
TMT B-A	Executive function	499	1337	26.00 ± 23.38	15.12 ± 14.41	10.88	8.69	13.08	< 0.001
Digit span backwards	Executive function	760	1613	4.87 ± 1.84	5.54 ± 1.97	− 0.67	− 0.83	− 0.5	< 0.001
Mental rotations	Perceptual-motor	682	1580	0.56 ± 0.17	0.62 ± 0.19	− 0.06	− 0.07	− 0.04	< 0.001
Confidence judgement	Meta-memory	749	1594	0.11 ± 0.08	0.11 ± 0.08	− 0,005	− 0.01	0,002	0.185

Results of the cognitive tests in relation to impaired kidney function (eGFR < 60 mL/min/1.73 m²) and normal kidney function (eGFR ≥60 mL/min/1.73 m²)
Some participants did not participate in all of the cognitive tests. Every participant performed at least one of the cognitive tests
Equal variances assumed for free recall, digit cancellation, pattern comparison and confidence judgement
Equal variances not assumed for MMSE, digit span forward, recognition, word fluency, TMT B-A, digit span backwards and mental rotations
Values following ± represent SD
Abbreviations: eGFR estimated glomerular filtration rate, CI Confidence interval, SD Standard deviation