Category intelligence | IQfs <−1 SD (n=60) | IQfs ≥−1 SD (n=66)‡ | p value* | IQv <−1 SD (n=55) | IQv ≥−1 SD (n=73)‡ | p value* | IQp <−1 SD (n=60) | IQp ≥−1 SD (n=68)‡ | p value* |
---|---|---|---|---|---|---|---|---|---|

*p value χ^{2} test; †number of patients; ‡in 2 patients only verbal IQ could be tested due to visual disabilities, and in 2 patients only performal IQ could be tested due to deafness (IQv n=128, IQp n=128; IQfs=126); §anaemia = Hb <5 mmol/l (<80 g/l); ¶RRT, renal replacement therapy. | |||||||||

Age at onset RRT¶: | |||||||||

<6 years (n)† | 2 | 3 | 1.0 | 2 | 3 | 1.0 | 2 | 3 | 1.0 |

≥6 years (n)† | 58 | 63 | 53 | 70 | 58 | 65 | |||

Duration of RRT¶: | |||||||||

<18 years (n)† | 30 | 31 | 0.85 | 25 | 36 | 0.72 | 33 | 30 | 0.29 |

≥18 years (n)† | 30 | 35 | 30 | 37 | 27 | 38 | |||

Duration of dialysis: | |||||||||

<4 (n)† | 34 | 51 | 0.02 | 32 | 53 | 0.09 | 36 | 50 | 0.13 |

≥4 (n)† | 26 | 15 | 23 | 20 | 24 | 18 | |||

Duration of anaemia§: | |||||||||

<1.5 y (n)† | 37 | 46 | 0.36 | 33 | 51 | 0.26 | 36 | 47 | 0.35 |

≥1.5 y (n)† | 23 | 20 | 22 | 22 | 24 | 21 | |||

Aluminium exposure: | |||||||||

Yes | 48 | 57 | 0.24 | 45 | 62 | 0.41 | 48 | 58 | 0.29 |

No | 12 | 9 | 10 | 11 | 12 | 10 | |||

RRT at investigation: | |||||||||

Dialysis (n)† | 15 | 13 | 0.54 | 10 | 19 | 0.39 | 14 | 15 | 0.52 |

Renal graft (n)† | 45 | 53 | 45 | 54 | 46 | 53 | |||

RRT onset: | |||||||||

1972–1981 (n)† | 32 | 38 | 0.38 | 31 | 41 | 0.56 | 29 | 41 | 0.12 |

1982–1992 (n)† | 28 | 28 | 24 | 32 | 31 | 27 | |||

Primary disease: | |||||||||

SLE, cystinosis (n)† | 4 | 0 | 0.05 | 4 | 0 | 0.03 | 4 | 0 | 0.05 |

Other disease (n)† | 56 | 66 | 51 | 73 | 56 | 68 |