A comparison between the CKD (n=92) and control (n =143) cohorts, demographic, clinical, and cognitive assessment outcomes (Mean ± SD, ratios)
| Controls (n=143) | G3* (n=48) | G4+5* (n=44) | P value† | |
| Age | 74.4±6.2 | 75.3±9.3 | 75.9±9.3 | 0.12‡ |
| Gender (male: female ratio) | 71:72 | 25:23 | 24:20 | 0.72¶ |
| Education years | 11.1 (1.8)§ | 11.1 (2.1)** | 10.6 (1.5)** | 0.007‡ |
| EQ-5D | 0.67 (0.19)§ | 0.55 (0.2)** | 0.53 (0.24)** | 0.03‡ |
| EQ-5D (visual analogue scale %) | 69.9 (14.3)§ | 63.8 (13.7)** | 50.1 (16.4)** | 0.04‡ |
| PHQ-9 | 2.5 (0.75) | 3.8 (1.7) | 4.1 (2.7) | 0.12‡ |
| ACE III (Global Score) | 91.9 (6.3) | 89.7 (6.8) | 88.3 (7.6) | 0.69‡ |
| ACE III cognitive subdomains | ||||
| Attention | 17.2 (1.4) | 17.3 (1.3) | 17.1 (1.5) | 0.69‡ |
| Memory | 22.6 (2.8) | 22.9 (2.1) | 22.5 (2.9) | 0.79‡ |
| Fluency | 11.1 (1.9) | 9.7 (1.6) | 9.7 (2.1) | 0.82‡ |
| Language | 24.8 (1.3) | 25.2 (1.3) | 24.9 (1.9) | 0.68‡ |
| Visuospatial | 14.6 (1.8) | 14.4 (2.0) | 13.9 (2.6) | 0.62‡ |
| Weigl Color Form Sorting Test | 3.6 (0.67) | 3.6 (0.72) | 3.5 (0.67) | 0.81‡ |
| TMT‡ (seconds) | 42.9 (9.2) | 44.2 (12.3) | 44.3 (12.7) | 0.38‡ |
| TMT¶ (seconds) | 101.1 (21.8)§ | 109.5 (20.1)** | 112.9 (31.4)** | 0.06‡ |
Categorical values are expressed as percentages or ratios. The mean ± SD and median values are reported for continuous variables. Lower mean scores represent a worse outcome for all tests except for the PHQ-9 and the TMT.
Because of the small numbers of patients in the Mild group (n= 10: eGFR 45 to < 60) they were combined with the Moderate group (N=38: 30 to <45) for ease of viewing.
*KIDIGO, Kidney Disease Improving Global Outcomes, stage of CKD: eGFR (estimated glomerular filtration rate) *Mild to Moderate 30 to <60: G3; Severe < 30: G4+5.
†Means across eGFR stages are equal = null hypothesis.
‡P-value calculated from ANOVA analysis of variance F-test.
§Numeric markers indicate significant differences between controls and CKD patients (by KIDIGO stage) within the same row, where ‘§’ marked on a row are different from any other group not marked ‘**’.
¶P value calculated from χ2 test.
ACE, Addenbrooke’s Cognitive Examination; ANOVA, analysis of variance; CKD, chronic kidney disease; PHQ-9, Patient Health Questionnaire-9; TMT, Trail Making Tests.