Table 3.

Predictors of HbA1c using a linear multilevel regression model

Variable	Category	HbA1c Estimate	95% CI	Category P value	Variable P value
Age	–	−0.02	(−0.02, −0.01)	–	<0.001
Townsend	–	0.02	(0.01, 0.03)	–	<0.001
Serum cholesterol	–	0.23	(0.22, 0.25)	–	<0.001
BMI	–	−0.002	(−0.005, 0.001)	–	0.227
Year	2004 (ref)	−	−	–	<0.001
	2005	−0.17	(−0.25, −0.1)	<0.001
	2006	−0.33	(−0.4, −0.26)	<0.001
	2007	−0.28	(−0.35, −0.21)	<0.001
	2008	−0.49	(−0.56, −0.42)	<0.001
	2009	−0.42	(−0.49, −0.35)	<0.001
Ethnicity	White (ref)	−	−	–	<0.001
	S Asian	0.36	(0.27, 0.44)	<0.001
	Black	0.32	(0.22, 0.42)	<0.001
Treatment	Metformin Only (ref)	−	−	–	<0.001
	Combined oral	0.42	(0.39, 0.45)	<0.001
	Insulin	1.05	(1.01, 1.09)	<0.001
Sex	Female (ref)	−	−	–	<0.001
	Male	0.11	(0.07, 0.15)	<0.001
Smoking status	Non–Smoker (ref)	−	−	–	<0.001
	Smoker	0.18	(0.13, 0.24)	<0.001
Ethnicity*Year	S Asian*2009	−0.11	(−0.19, −0.03)	0.007	<0.001
	Black*2009	−0.20	(−0.3, −0.09)	<0.001