Table 1.
Characteristics (%) of ≥ 50 years old patients initiating metformin (MET) and sulfonylurea (SU) from the Veterans Health Administration (VHA; FY2002 to FY2012) and Kaiser Permanente Washington State (KPW; 1996–2012) health care systems
| Covariates | VHA (n=75,187) | KPWa (n=10,866) |
|---|---|---|
| Index year | ||
| 1996–1998 | - | 12.8 |
| 1999–2000 | - | 10.2 |
| 2001–2002 | - | 11.2 |
| 2002–2004 | 5.6 | - |
| 2003–2004 | - | 12.2 |
| 2005–2006 | 32.5 | 14.6 |
| 2007–2008 | 26.3 | 14.0 |
| 2009–2012 | - | 25.1 |
| 2009–2010 | 20.8 | - |
| 2011–2012 | 14.8 | - |
| Sociodemographic-related | ||
| Age, mean (±sd) | 60.8 (±8.5) | 63.1 (±9.5) |
| Age category | ||
| 50–64 | 66.8 | 61.7 |
| 65–74 | 24.6 | 23.9 |
| ≥ 75 | 8.6 | 14.3 |
| Male gender | 96.8 | 50.4 |
| Race | ||
| White | 84.1 | 74.4 |
| Black | 14.0 | 4.1 |
| Asian | -- | 7.5 |
| Other | 1.9 | 3.0 |
| Unknown | -- | 11.0 |
| Race (excluding unknown) | ||
| White | -- | 83.6 |
| Black | -- | 4.6 |
| Asian | -- | 8.4 |
| Other | -- | 3.4 |
| Married | 59.3 | - |
| Low nSES b | 50.0 | 49.8 |
| VHA only insurance | 45.9 | - |
| Medicaid/Medicare | - | 38.9 |
| High healthcare utilization | 25.0 | 24.9 |
| Diabetes-related | ||
| Diabetic nephropathy | 1.2 | 1.9 |
| Diabetic retinopathy | 5.2 | 3.1 |
| Diabetic neuropathy | 7.2 | 8.3 |
| HbA1c value, mean (±sd) | 7.2 (±1.4) | 8.6 (±2.0) |
| HbA1c category | ||
| < 7 | 51.2 | 17.8 |
| 7–8 | 31.0 | 29.2 |
| > 8 | 17.8 | 53.1 |
| Creatinine value, mean (±sd) | 1.0 (±0.2) | 0.9 (±0.2) |
| Other comorbidities | ||
| Obesity | 59.5 | 50.3 |
| Hypertension | 90.9 | 57.9 |
| Hyperlipidemia | 86.9 | 40.1 |
| Stroke | 6.8 | 2.2 |
| Ischemic heart disease | 47.7 | 15.9 |
| Congestive heart failure | 17.5 | 5.4 |
| Atrial fibrillation | 13.2 | 6.7 |
| Traumatic brain injury | 6.3 | 1.4 |
| Vitamin B12 deficiency | 4.9 | 0.8 |
| Psychiatric and substance comorbidities | ||
| Depression | 28.6 | 4.4 |
| PTSD | 19.5 | 0.4 |
| Other anxiety c | 13.7 | 2.8 |
| Bipolar disorder | 7.7 | 1.7 |
| Schizophrenia | 5.5 | 0.3 |
| Nicotine abuse/dependence | 53.1 | 17.2 |
| Alcohol abuse/dependence | 16.1 | 1.9 |
| Illicit drug abuse/dependence | 8.1 | 0.6 |
| Other medications d | ||
| Statins | 69.5 | 36.9 |
| Anticholinergics | 45.0 | 23.4 |
| NSAIDs | 56.1 | 19.1 |
| Antihypertensives | 87.7 | 44.5 |
KPW dynamic cohort – covariates measured for 2 year prior to every new metformin/sulfonylurea start; VHA=Veterans Health Administration; KPW=Kaiser Permanente Washington State; FY=Fiscal Year; MET=Metformin; SU=Sulfonylurea;
nSES = top 50th vs. bottom 50th percentile of neighborhood socioeconomic status based on information from 7 measures of SES obtained from 2009–2013 5-year census estimates from the American Community Survey
Other anxiety disorders = panic disorder, OCD, social phobia, GAD, Anxiety NOS
Other medications associated with dementia= sustained use prior to MET or SU (at least 2 fills in a 6 month period)