Characteristics of patients in the propensity score–matched cohort*
| Characteristic | No. (%) of patients† | ||
|---|---|---|---|
| Metformin + sulfonylurea n = 12 180 | Metformin + insulin n = 2 436 | Standardized difference‡ | |
| Age, median (IQR), yr | 60 (54–68) | 60 (55–68) | 0.02 |
| Sex, male | 11 521 (95) | 2 315 (95) | 0.02 |
| Race | |||
| White | 8 612 (71) | 1 726 (71) | 0.00 |
| Black | 2 028 (17) | 400 (16) | −0.01 |
| Other | 512 (4) | 111 (5) | 0.02 |
| Missing | 1 028 (8) | 199 (8) | −0.01 |
| Time to intensification,§ median (IQR), mo | 14 (6–31) | 14 (5–30) | −0.01 |
| HbA1C, median (IQR), % | 8.1 (7.2–9.9) | 8.1 (6.9–9.9) | −0.07 |
| eGFR, median (IQR), mL/min | 82 (70–98) | 82 (70–98) | 0.01 |
| Systolic blood pressure, median (IQR), mm Hg | 131 (120–143) | 131 (120–142) | 0.01 |
| Body mass index, median (IQR) | 32.3 (28.6–37.0) | 32.6 (28.4–37.1) | 0.00 |
| Baseline comorbidities¶ | |||
| Malignant disease | 1 115 (9) | 223 (9) | 0.00 |
| Congestive heart failure | 1 053 (9) | 209 (9) | 0.00 |
| Cardiovascular disease | 4 125 (34) | 825 (34) | 0.00 |
| Serious mental illness | 3 878 (32) | 768 (32) | −0.01 |
| Chronic obstructive pulmonary disease | 2 378 (20) | 481 (20) | 0.01 |
| Arrhythmia | 1 274 (10) | 255 (10) | 0.00 |
| Use of medications | |||
| ACE inhibitor or ARB | 8 576 (70) | 1 727 (71) | 0.01 |
| Antihypertensive medication | 8 894 (73) | 1 762 (72) | −0.02 |
| Statin or nonstatin lipid-lowering agent | 9 250 (76) | 1 858 (76) | 0.01 |
| Anticoagulant, platelet inhibitor | 1 849 (15) | 363 (15) | −0.01 |
| Nitrate | 1 472 (12) | 297 (12) | 0.00 |
| ASA | 3 411 (28) | 666 (27) | −0.02 |
| Antipsychotic | 1 436 (12) | 279 (11) | −0.01 |
| Indicators of health care use | |||
| Admitted to hospital in last year | 3 274 (27) | 631 (26) | −0.03 |
| Nursing home encounter | 24 (0.2) | 4 (0.2) | −0.01 |
| Outpatient visits in past year, median (IQR) | 7 (4–12) | 7 (4–12) | −0.03 |
| Medicare use in last year | 4 191 (34) | 843 (35) | 0.00 |
| Medicaid use in last year | 590 (5) | 122 (5) | 0.01 |
Note: ACE = angiotensin-converting enzyme, ARB = angiotensin-receptor blocker, ASA = acetylsalicylic acid, eGFR = estimated glomerular filtration rate, IQR = interquartile range.
↵* Full table of characteristics available in Appendix 1, Supplemental Table 2 (www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.150904/-/DC1).
↵† Unless stated otherwise.
↵‡ Standardized differences are the absolute difference in means or percent divided by an evenly weighted pooled standard deviation, or the difference between groups in number of standard deviations. In the matched cohort, all standardized differences were insignificant except HbA1C at p = 0.05.
↵§ Time to treatment intensification represents the median number of months taking metformin monotherapy. It is an approximation of diabetes duration since patients were free of all hypoglycemic medications for 180 days prior to starting metformin.
↵¶ Definitions of comorbidities available in Appendix 1, Supplemental Table 1.