Table 5

Association between determinants and poor Full Scale Intelligence Quotient (IQfs <−1 SD), poor Verbal Intelligence Quotient (IQv <−1 SD), and poor Performal Intelligence Quotient (IQp <−1 SD): univariate analysis

Category intelligenceIQfs <−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 χ2 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)†231.0231.0231.0
    ≥6 years (n)†586353705865
Duration of RRT¶:
    <18 years (n)†30310.8525360.7233300.29
    ≥18 years (n)†303530372738
Duration of dialysis:
    <4 (n)†34510.0232530.0936500.13
    ≥4 (n)†261523202418
Duration of anaemia§:
    <1.5 y (n)†37460.3633510.2636470.35
    ≥1.5 y (n)†232022222421
Aluminium exposure:
    Yes48570.2445620.4148580.29
    No12910111210
RRT at investigation:
    Dialysis (n)†15130.5410190.3914150.52
    Renal graft (n)†455345544653
RRT onset:
    1972–1981 (n)†32380.3831410.5629410.12
    1982–1992 (n)†282824323127
Primary disease:
    SLE, cystinosis (n)†400.05400.03400.05
    Other disease (n)†566651735668