Table 4

Characteristics of adults with diabetes and routine access to care who are FDA ineligible for metformin, NHANES 1999–2010

Metformin is contraindicated: MDRD eGFR <30
mL/min/1.73 m2
Indeterminant: MDRD eGFR 30–44
mL/min/1.73 m2
Metformin is likely safe: MDRD eGFR ≥45 mL/min/1.73 m2
Of study N = 122Of national estimate
N = 444,800
Of study
N = 170
Of national estimate
N = 734,900
Of study N = 50Of national estimate
N = 148,700
P2 or ANOVA)***
Male sex54 (44.3)158,30097 (57.1)384,53348 (96.0)139,200<0.001
Age (years)0.00
 20–391 (0.8)5,7000 (0.0)02 (4.0)8,100
 40–5918 (14.8)77,30013 (7.7)63,3005 (10.0)38,200
 60–6940 (32.8)117,60044 (25.9)206,40023 (46.0)64,400
 70+63 (51.6)244,200113 (66.5)465,20020 (40.0)38,000
Race/ethnicity**<0.001
 White41 (33.6)257,30096 (56.5)546,4005 (10.0)32,400
 Non-Hispanic black40 (32.8)103,10044 (25.9)125,90040 (80.0)86,400
 Hispanic33 (27.1)39,40022 (12.9)35,2003 (6.0)1,900
Yearly family income ($)2 (4.0)0.20
 <20,00038 (35.2)117,70072 (47.1)300,00014 (30.4)39,200
 20,000–44,99951 (47.2)214,00051 (33.3)220,00020 (43.5)43,300
 45,000–74,99914 (13.0)48,00019 (12.4)86,5008 (17.4)30,100
 ≥75,0005 (4.6)23,00011 (7.2)56,1004 (8.7)30,700
Has health insurance118 (96.7)438,600163 (95.9)701,50046 (92.0)136,5000.37
More than high school education49 (49.5)208,20066 (50.0)334,60022 (55.0)89,3000.82
Hypertension*100 (82.6)365,100127 (75.2)570,30040 (81.6)123,2000.27
Glycemic control: A1C0.32
<7% (<53 mmol/mol)74 (61.2)295,20099 (58.2)444,20027 (54.0)78,000
7–<8% (53–63 mmol/mol)27 (22.3)83,70040 (23.5)183,3007 (14.0)18,000
8–<9% (64–74 mmol/mol)20 (8.3)28,00016 (9.4)65,3007 (14.0)10,700
≥9% (>75 mmol/mol)10 (8.3)35,30015 (8.8)42,4009 (18.0)41,900
BMI (kg/m2), mean (SD)31.7 (6.5)33.3 (9.1)32.4 (8.9)0.31
Urine albumin-to-creatinine ratio (mg/g)<0.001
≤3018 (18.2)63,50066 (42.0)312,70019 (39.6)63,700
31–29932 (32.2)151,80060 (38.3)229,30019 (39.6)53,300
300–1,00014 (14.1)49,10013 (8.3)65,6006 (12.5)13,600
>1,00035 (35.4)117,30018 (11.5)78,8004 (8.3)14,000
  • Data are n (%) or n unless otherwise indicated. FDA ineligible for metformin: sCr ≥1.4 mg/dL for women and ≥1.5 mg/dL for men. Sample size = 342; weights used to produce U.S. national estimates. Diabetes is self-reported or A1C >6.5%.

  • ***P values refer to differences among actual study participants—not national estimates.

  • **“Other” not shown owing to small sample size but included in all analyses.

  • *Hypertension defined by average blood pressure >140/90 mmHg or self-reported antihypertensive use.