Table 2.

Competing-risk model of variables associated with the cumulative incidence of ESRD in patients with type 1 diabetes and macroalbuminuria from the FinnDiane cohort

Predictor VariablesSubhazard Ratio[95% CI]P
Men1.961.39 to 2.760.001
Estimated GFR (FP)a0.050.04 to 0.070.001
LDL cholesterol (FP)a1.011.00 to 1.010.001
Duration of diabetes (years)0.970.95 to 0.990.028
HbA1c (%)1.311.15 to 1.480.001
Body mass index (FP)a2815.13 to 15480.006
Insulin dose (FP)a0.870.79 to 0.970.010
Insulin dose (FP)a0.300.13 to 0.690.005
  • 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: β0 + β1x2 + β2x2 log x, where β0 is the intercept and x the continuous covariate.26 Duration of diabetes and HbA1c 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.

  • aGFR, 0 (log); LDL cholesterol, 3rd degree; body mass index, −2; insulin dose, −2 3.