Table 1.
Characteristics of warfarin users under study, by antihyperlipidemic cohort.
| Antihyperlipidemic of interest | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| atorva | ceriva* | feno | fluva* | gem | lova | pitava* | prava | rosuva | simva | ||
| Persons | 219 | ** | 24 | ** | 11 | 36 | ** | 68 | 22 | 235 | |
| Persons-days of observation period, median (Q1-Q3) per individual | 112.0 (45.0–197.0) | 79.5 (31.5–128.0) | 98.0 (57.5–217.0) | 66.0 (43.0–110.0) | 43.0 (29.0–126.0) | 74.5 (40.5–189.0) | 17.0 (17.0–17.0) | 102.0 (53.0–203.5) | 109.0 (57.0–171.0) | 100.0 (46.0–190.0) | |
| Person-days of observation period, total | 34,789 | 319 | 3,772 | 1,156 | 811 | 4,726 | 17 | 10,610 | 2,585 | 34,979 | |
| % person-days of observation period in risk segment | 13.5 | 23.2 | 13.2 | 23.8 | 28.0 | 12.5 | 0.0 | 12.6 | 11.7 | 10.6 | |
| Outcomes during observation period | 238 | ** | 27 | 11 | 11 | 38 | ** | 73 | 23 | 248 | |
| VTE | 170 | ** | ** | ** | ** | 26 | ** | 52 | ** | 162 | |
| IS | 68 | 0 | ** | ** | ** | 12 | 0 | 21 | ** | 86 | |
| Demographics | Group | % of persons (unless otherwise noted) | |||||||||
| Age in years at start of observation period | Median (Q1-Q3) | 68.9 (54.3–78.1) | 80.5 (72.0–86.5) | 61.3 (48.4–69.9) | 66.5 (51.8–84.0) | 57.3 (46.1–63.4) | 72.2 (57.1–80.2) | 62.5 (62.5–62.5) | 71.4 (57.2–78.7) | 63.8 (55.3–74.4) | 71.1 (59.4–80.0) |
| Sex | Female | 69.9 | ** | 66.7 | ** | ** | 61.1 | ** | 58.8 | 77.3 | 62.6 |
| Race | White | 60.3 | ** | 79.2 | ** | ** | 55.6 | 0.0 | 60.3 | ** | 51.9 |
| Black | 16.9 | ** | ** | 0.0 | ** | ** | ** | ** | ** | 23.8 | |
| Hispanic/Latino | 8.7 | 0.0 | 0.0 | ** | ** | ** | 0.0 | ** | ** | 11.5 | |
| Other/Unknown | 14.2 | ** | ** | ** | ** | ** | ** | ** | ** | 12.8 | |
| State of residence | California | 39.3 | ** | ** | ** | ** | 41.7 | 0.0 | 54.4 | ** | 29.8 |
| Florida | 14.2 | ** | ** | ** | ** | ** | ** | 17.6 | ** | 17.9 | |
| New York | 24.2 | 0.0 | ** | ** | ** | ** | 0.0 | ** | ** | 26.0 | |
| Ohio | 13.2 | ** | ** | ** | ** | ** | ** | ** | ** | 12.3 | |
| Pennsylvania | 9.1 | 0.0 | ** | ** | ** | ** | 0.0 | ** | ** | 14.0 | |
| Calendar year at start of observation period† | 1999 | ** | ** | ** | ** | 0.0 | ** | 0.0 | ** | 0.0 | ** |
| 2000 | ** | ** | 0.0 | ** | ** | ** | 0.0 | ** | 0.0 | ** | |
| 2001 | 10.0 | ** | ** | ** | ** | ** | 0.0 | ** | 0.0 | 5.5 | |
| 2002 | 9.6 | 0.0 | 0.0 | 0.0 | ** | ** | 0.0 | ** | 0.0 | 4.7 | |
| 2003 | 7.3 | 0.0 | ** | ** | 0.0 | ** | 0.0 | ** | 0.0 | 4.7 | |
| 2004 | 8.2 | 0.0 | 0.0 | ** | ** | ** | 0.0 | ** | 0.0 | ** | |
| 2005 | 10.5 | 0.0 | ** | 0.0 | ** | ** | 0.0 | ** | ** | ** | |
| 2006 | 12.3 | 0.0 | ** | 0.0 | 0.0 | ** | 0.0 | ** | ** | 4.7 | |
| 2007 | 9.1 | 0.0 | ** | ** | 0.0 | ** | 0.0 | ** | 0.0 | 11.5 | |
| 2008 | 10.5 | 0.0 | ** | 0.0 | ** | ** | 0.0 | ** | ** | 13.6 | |
| 2009 | 8.7 | 0.0 | ** | 0.0 | ** | ** | 0.0 | ** | ** | 14.5 | |
| 2010 | 5.5 | 0.0 | ** | 0.0 | ** | ** | 0.0 | ** | ** | 17.4 | |
| 2011 | ** | 0.0 | ** | 0.0 | 0.0 | ** | ** | ** | ** | 14.9 | |
| Medicare enrolled at start of observation period | Yes | 79.0 | ** | 75.0 | ** | ** | 88.9 | ** | 88.2 | 81.8 | 77.4 |
| Nursing home resident at start of observation period | 8.7 | ** | ** | ** | ** | ** | ** | ** | ** | 17.4 | |
| Pre-defined time-varying covariates | Group | % of person-days (unless otherwise noted) | |||||||||
| Major non-chronic risk factor for outcome | |||||||||||
| VTE in prior 90 days | Yes | 30.3 | 68.0 | 54.9 | 17.9 | 69.2 | 32.2 | ** | 30.9 | 38.4 | 28.9 |
| IS in prior 90 days | 9.0 | 0.0 | 3.2 | 12.5 | 5.5 | 7.5 | 0.0 | 8.5 | 20.0 | 12.4 | |
| Hospital discharge on current day or in prior 90 days | 31.6 | 49.2 | 41.6 | 35.7 | 70.4 | 36.1 | ** | 30.2 | 41.5 | 34.2 | |
| Major non-chronic disease that may affect coagulation | |||||||||||
| Acute infection on current day or in prior 14 days | Yes | 15.3 | 16.9 | 10.5 | 15.6 | 14.1 | 10.5 | ** | 16.7 | 16.1 | 15.3 |
| Drug that may affect coagulation† | |||||||||||
| anticoagulant, oral non-warfarin | Yes | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| anticoagulant, injectable/subcutaneous | 0.9 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.8 | 1.2 | 0.5 | |
| antiplatelet, oral | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| aspirin | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Drug that may interact with warfarin | |||||||||||
| interacting drug, oral, per Truven‡ | Yes | 29.3 | 42.9 | 30.4 | 10.4 | 26.3 | 38.6 | 0.0 | 30.7 | 12.4 | 17.3 |
| CYP2C9 inhibitor‡ | 11.0 | 42.6 | 15.6 | 0.0 | 7.5 | 10.3 | 0.0 | 8.4 | 2.3 | 5.0 | |
| CYP2C9 inducer† | 5.8 | 0.0 | 0.0 | 0.0 | 0.0 | 0.6 | 0.0 | 6.1 | 0.0 | 1.6 | |
| Drug that may increase risk of VTE alone† | Yes | 26.7 | 0.0 | 31.0 | 11.5 | 55.7 | 40.3 | 0.0 | 19.5 | 19.1 | 21.9 |
| Drug that may increase risk of IS alone‡ | Yes | 24.8 | 42.6 | 30.0 | 3.1 | 9.0 | 25.0 | 0.0 | 19.5 | 13.2 | 23.8 |
| Drug that may increase risk of VTE and IS† | Yes | 15.9 | 46.1 | 17.7 | 12.8 | 24.7 | 26.2 | 0.0 | 19.1 | 18.8 | 10.2 |
| Therapeutic drug monitoring for warfarin | Yes | 32.5 | 41.1 | 31.8 | 27.3 | 29.1 | 28.0 | 0.0 | 31.0 | 31.8 | 31.1 |
| Average daily warfarin dose, in milligrams | Median (Q1-Q3) | 4.8 (2.5–5.0) | 4.0 (4.0–4.0) | 3.0 (2.0–5.0) | 4.0 (2.5–5.0) | 5.0 (3.7–6.0) | 5.0 (2.5–5.0) | 7.5 (7.5–7.5) | 2.5 (1.5–5.0) | 3.0 (2.0–5.0) | 4.0 (2.0–5.0) |
Atorva = atorvastatin; CYP = cytochrome P450; feno = fenofibrate; gem = gemfibrozil; IS = ischemic stroke; lova = lovastatin; prava = pravastatin; Q = quartile; rosuva = rosuvastatin; simva = simvastatin; VTE = venous thromboembolism.
*Excluded from further study because few persons in cohort.
**Value suppressed to ensure subject anonymity, consistent with Centers for Medicare and Medicaid Services privacy rule for small cells; cell < 11 or would permit back-calculation of a cell < 11.
†If dispensed on current day or in prior 30 days.
‡If dispensed on current day or in prior 30 days for chronically-administered drugs (14 days for acutely-administered drugs).