Table 1.

Fractional polynomial models for effect of cumulative duration of past amiodarone use on the risk of thyroid dysfunction

Model	Deviance D	P	Step	Comparison	Deviance difference	p-value
FP2	16 772.87	1, 1	1	FP2 versus null	371.72	<0.0001 (4 d.f.)
FP1	16 783.91	0	2	FP2 versus linear	103.80	<0.0001 (3 d.f.)
Linear	16 876.67	1	3	FP2 versus FP1	11.04	0.0040 (2 d.f.)
Null	17 144.59