Table 2.
Comparison of Propensity Matched Metformin Users and Nonusers Hospitalized With Pneumonia
| Variables | Metformin (n = 6899) | No Metformin (n = 6899) | P | Standardized Difference |
|---|---|---|---|---|
| Demographics | ||||
| Age, mean (SD) | 75.1 (6.6) | 75.1 (6.6) | .97 | 0.0005 |
| Men | 6806 (98.7%) | 6806 (98.7%) | 1.0 | 0.0000 |
| Race | ||||
| White | 5710 (82.3%) | 5729 (83.0%) | .20 | 0.007 |
| Black | 691 (10.0%) | 686 (9.9%) | .90 | −0.0024 |
| Hispanic | 526 (7.6%) | 525 (7.6%) | .97 | −0.0006 |
| Nursing home residence | 103 (1.5%) | 104 (1.5%) | .94 | 0.001 |
| Socioeconomic proxies | .91 | 0.005 | ||
| VA priority group 1 | 1553 (22.5%) | 1533 (22.2%) | ||
| VA priority groups 2–6 | 4619 (67.0%) | 4634 (67.1%) | ||
| VA priority groups 7–8 | 727 (10.5%) | 732 (10.6%) | ||
| No. of outpatient visits the year prior to admission, mean (SD) | 17.9 (13.3) | 18.0 (14.2) | .76 | −0.005 |
| Characteristics of hospitalization | ||||
| ICU admission | 1201 (17.4%) | 1156 (16.8%) | .31 | −0.02 |
| Invasive mechanical ventilation | 468 (6.9%) | 465 (6.7%) | .91 | −0.002 |
| Noninvasive mechanical ventilation | 367 (5.3%) | 353 (5.1%) | .60 | −0.009 |
| Vasopressors | 342 (5.0%) | 336 (4.9%) | .81 | −0.004 |
| Guideline-concordant antibiotics | 5727 (83.0%) | 5724 (83.0) | .95 | −0.001 |
| Comorbid conditions | ||||
| Tobacco use | 2952 (42.8%) | 2964 (43.0%) | .84 | 0.003 |
| Alcohol abuse | 193 (2.8%) | 190 (2.8%) | .88 | −0.003 |
| Illicit drug abuse | 77 (1.1%) | 76 (1.1%) | .94 | 0.001 |
| Myocardial infarction | 511 (7.4%) | 509 (7.4%) | .95 | −0.001 |
| Heart failure | 1661 (24.1%) | 1714 (24.8%) | .30 | 0.02 |
| Peripheral vascular disease | 1228 (18.0%) | 1271 (18.4%) | .34 | 0.02 |
| Stroke | 1232 (17.9%) | 1283 (18.6%) | .26 | 0.02 |
| Chronic obstructive pulmonary disease | 3398 (49.3%) | 3475 (50.4%) | .19 | 0.02 |
| Rheumatologic disease | 144 (2.1%) | 165 (2.4%) | .23 | 0.02 |
| Mild liver disease | 36 (0.5%) | 22 (0.3%) | .07 | −0.03 |
| Peptic ulcer disease | 163 (2.4%) | 171 (2.5%) | .66 | 0.008 |
| Dementia | 222 (3.2%) | 232 (3.4%) | .63 | 0.0078 |
| Diabetes | 6824 (98.9%) | 6834 (99.1%) | .40 | 0.01 |
| Diabetes with complications | 1904 (27.6%) | 1866 (27.1%) | .47 | −0.01 |
| Hemiplegia | 103 (1.5%) | 88 (1.3%) | .31 | −0.02 |
| Renal disease | 430 (6.2%) | 431 (6.3%) | .97 | 0.0006 |
| Any prior malignancy | 1583 (22.9%) | 1569 (22.7%) | .78 | −0.005 |
| Metastatic solid tumor | 261 (3.8%) | 72 (3.9%) | .63 | 0.008 |
| Hematologic malignancy | 163 (2.4%) | 180 (2.6%) | .35 | 0.02 |
| HIV | 4 (0.1%) | 5 (0.1%) | .73 | 0.005 |
| Outpatient medications | ||||
| Antipsychotic agents | 451 (6.5%) | 465 (6.7%) | .20 | 0.01 |
| Antiplatelet agents | 753 (10.9%) | 779 (11.2%) | .44 | 0.007 |
| Statins | 4004 (58.0%) | 3963 (57.4%) | .14 | −0.007 |
| ARBs | 780 (11.3%) | 768 (12.5%) | .47 | −0.004 |
| ACE inhibitors | 3888 (56.4%) | 3920 (56.8%) | .31 | 0.01 |
| Antiarrhythmics | 223 (3.2%) | 253 (3.7%) | .24 | 0.02 |
| B-Blockers | 3184 (46.2%) | 3202 (46.4%) | .22 | 0.009 |
| Calcium channel blockers | 2230 (32.3%) | 2253 (32.7%) | .45 | 0.01 |
| Diuretics | 4199 (60.9%) | 4324 (62.7%) | .15 | 0.03 |
| Nitrate antianginal medications | 1317 (19.0%) | 1357 (19.7%) | .69 | 0.01 |
| Other antihypertensive medications | 1708 (24.9%) | 1624 (23.5%) | .07 | −0.02 |
| Insulin | 1675 (24.3%) | 1679 (24.3%) | .94 | 0.001 |
| B-Agonist bronchodilators | 2468 (35.8%) | 2558 (37.0%) | .59 | 0.02 |
| Theophylline | 208 (3.0%) | 213 (3.1%) | .81 | 0.004 |
| Other cardiac medications | 5716 (82.9%) | 5658 (82.0%) | .13 | 0.02 |
| Other inhaled medications | 1822 (26.4%) | 1753 (25.4%) | .66 | 0.03 |
| Other injectable medications | 390 (5.7%) | 422 (6.1%) | .43 | 0.02 |
| Oral corticosteroids | 1324 (19.2%) | 1358 (19.7%) | .23 | 0.01 |
| Other pulmonary medications | 2634 (38.2%) | 2732 (39.6%) | .28 | 0.02 |
| Other bronchodilators | 2390 (34.6%) | 2449 (35.5%) | .27 | 0.01 |
| Antibiotics within 90 days prior to hospitalization | 1930 (28.0%) | 1964 (28.4%) | .52 | 0.01 |
Data are presented as no. (%) unless otherwise indicated. Abbreviations: ACE, angiotensin-converting enzyme; ARB, angiotensin II receptor blocker; HIV, human immunodeficiency virus; ICU, intensive care unit; SD, standard deviation; VA, Veterans Affairs.