Predictor Variables | Subhazard Ratio | [95% CI] | P |
---|---|---|---|

Men | 1.96 | 1.39 to 2.76 | 0.001 |

Estimated GFR (FP)^{a} | 0.05 | 0.04 to 0.07 | 0.001 |

LDL cholesterol (FP)^{a} | 1.01 | 1.00 to 1.01 | 0.001 |

Duration of diabetes (years) | 0.97 | 0.95 to 0.99 | 0.028 |

HbA_{1c} (%) | 1.31 | 1.15 to 1.48 | 0.001 |

Body mass index (FP)^{a} | 281 | 5.13 to 1548 | 0.006 |

Insulin dose (FP)^{a} | 0.87 | 0.79 to 0.97 | 0.010 |

Insulin dose (FP)^{a} | 0.30 | 0.13 to 0.69 | 0.005 |

For graphical interpretation, see Figure 2. FP, fractional polynomial. Fractional polynomials are extensions of the conventional polynomial, allowing unique and repeated powers of a (positive) continuous variable, the powers being (−2, −1, −0.5, 0, 0.5, 1, 2, 3) and the power 0 = logarithm. Thus, a 2,2 fractional polynomial has the general form: β

_{0}+ β_{1}*x*^{2}+ β_{2}*x*^{2}log*x*, where β_{0}is the intercept and*x*the continuous covariate.^{26}Duration of diabetes and HbA_{1c}are parameterized as linear variables. Baseline category for gender = female. The coefficient effects represented by FP are not subject to literal effect interpretation (compared with other coefficients) as the underlying scale was further transformed in the process of FP generation.↵

^{a}GFR, 0 (log); LDL cholesterol, 3rd degree; body mass index, −2; insulin dose, −2 3.