Table 2 –

Unadjusted and adjusted analysis to examine the association between duration of metformin use and development of peripheral neuropathy among older adults with Type 2 Diabetes Mellitus seeking outpatient care at U.S. Veterans Affairs Medical Centers, 2002–2015.

	Unadjusted Analysis		Adjusted Analysis*
	OR (95% CI)	P-value	OR (95% CI)	P-value
Months of metformin use
Continuous	1.01 (1.01–1.01)	<0.0001	1.009 (1.009–1.01)	<0.0001
Categorical
6–<18	Ref		Ref
18 –<44.1	1.78 (1.73–1.83)	<0.0001	1.57 (1.51–1.63)	<0.0001
44.1–< 61	2.45 (2.37–2.54)	<0.0001	2.05 (1.97–2.14)	<0.0001
61+	3.19 (3.09–3.29)	<0.0001	2.69 (2.58–2.79)	<0.0001
Age (years)	0.99 (0.99–0.99)	<0.0001	1.00 (0.99–1.00)	0.4218
BMI (kg/m2)	1.02 (1.02–1.03)	<0.0001	1.02 (1.017–1.02)	<0.0001
Duration treated at the VAMC (years)	1.07 (1.07–1.08)	<0.0001	1.02 (1.01–1.02)	<0.0001
eGFR (mL/min/1.73 m2)	1.005 (1.004–1.005)	<0.0001	1.00 (0.99–1.00)	0.3540
Race and Ethnicity
Non-Hispanic White	Ref		Ref
Non-Hispanic Black	0.84 (0.82–0.87)	<0.0001	0.82 (0.79–0.85)	<0.0001
Other	0.69 (0.64–0.76)	<0.0001	0.73 (0.67–0.79)	<0.0001
Sex
Female	Ref		Ref
Male	1.38 (1.30–1.47)	<0.0001	1.34 (1.26–1.43)	<0.0001
Smoking
Never Smoker	Ref		Ref
Ever Smoker	1.17 (1.14–1.21)	<0.0001	1.02 (0.99–1.05)	0.1931
Unknown smoking status	0.90 (0.84–0.97)	0.004	1.07 (1.00–1.15)	0.0605
Alcohol abuse
Absent	Ref		Ref
Present	1.64 (1.58–1.69)	<0.0001	1.34 (1.29 – 1.39)	<0.0001
Received vitamin B12 assessment
No	Ref		Ref
Yes	2.19 (2.14–2.25)	<0.0001	1.69 (1.64–1.73)	<0.0001
Serum vitamin B12 (pg/dL)
Unknown	0.45 (0.44–0.46)	<0.0001	–	–
<170	0.95 (0.88–1.03)	0.21	0.72 (0.67–0.78)	<0.0001
170-<300	0.97 (0.94–1.01)	0.09	0.86 (0.83–0.89)	<0.0001
≥300	Ref		Ref
Received vitamin B12 treatment
No	Ref		Ref
Yes	1.94 (1.89–1.98)	<0.0001	1.53 (1.49–1.57)	<0.0001

BMI: body mass index; VAMC: U.S. Veterans Affairs Medical Centers; eGFR: estimated glomerular filtration rate.

^*Each variable is adjusted for all other variables in the model.