Table 1.
Patient characteristics before and after inverse probability treatment weighting (IPTW).
| Patient characteristics | Before IPTW | After IPTW | ||||
|---|---|---|---|---|---|---|
| Warfarin Use (n = 1,651) | No use (n = 4,114) | Standardized difference | Warfarin Use | No use | Standardized difference | |
| Demographics | ||||||
| Age at AF diagnosis, mean (year) | 73.9 | 75.1 | −0.180 | 74.4 | 74.7 | −0.043 |
| Female sex, % | 56.4 | 57.0 | −0.011 | 57.0 | 56.8 | 0.003 |
| Non-white, % | 35.6 | 37.9 | −0.048 | 37.3 | 37.3 | −0.001 |
| Hispanic, % | 19.0 | 18.8 | 0.003 | 18.6 | 18.8 | −0.006 |
| Year of AF diagnosis, % | ||||||
| 2007 | 24.7 | 22.8 | 0.042 | 23.8 | 23.4 | 0.009 |
| 2008 | 28.0 | 26.8 | 0.027 | 26.8 | 27.0 | −0.004 |
| 2009 | 21.6 | 20.8 | 0.020 | 21.4 | 21.0 | 0.011 |
| 2010 | 17.6 | 17.9 | −0.010 | 17.8 | 17.9 | −0.001 |
| 2011 | 8.2 | 11.7 | −0.116 | 10.1 | 10.7 | −0.020 |
| Dialysis vintage, mean (year) | 4.3 | 4.5 | −0.054 | 4.4 | 4.4 | −0.004 |
| Modality, % | ||||||
| Hemodialysis | 96.0 | 96.9 | −0.049 | 96.2 | 96.6 | −0.020 |
| Peritoneal dialysis | 4.0 | 3.1 | 0.049 | 3.8 | 3.4 | 0.020 |
| Geographic region, % | ||||||
| Northeast | 19.2 | 16.9 | 0.059 | 18.1 | 17.6 | 0.013 |
| Midwest | 23.4 | 20.0 | 0.081 | 21.6 | 21.0 | 0.015 |
| South | 41.6 | 45.1 | −0.072 | 43.6 | 44.2 | −0.011 |
| West | 15.9 | 17.9 | −0.054 | 16.7 | 17.3 | −0.015 |
| History of medication use, % | ||||||
| Anticoagulant agent | 0.8 | 0.6 | 0.028 | 0.7 | 0.6 | 0.009 |
| Antiplatelet agent | 25.9 | 25.1 | 0.017 | 25.8 | 25.3 | 0.011 |
| Beta-Blocker | 43.7 | 43.6 | 0.002 | 43.6 | 43.6 | −0.000 |
| Calcium channel blocker | 48.2 | 47.3 | 0.018 | 47.6 | 47.6 | 0.001 |
| Calcium acetate | 31.6 | 31.8 | −0.005 | 31.7 | 31.7 | −0.000 |
| Central acting agonist | 15.7 | 16.6 | −0.024 | 16.2 | 16.4 | −0.003 |
| Diuretic | 20.5 | 20.4 | 0.002 | 20.1 | 20.4 | −0.009 |
| Lipid-lowering agent, nonstatin | 8.0 | 7.9 | 0.004 | 8.1 | 7.9 | 0.007 |
| Nitrate | 23.1 | 23.5 | −0.011 | 23.9 | 23.5 | 0.008 |
| NSAID | 8.7 | 9.3 | −0.021 | 8.7 | 9.0 | −0.012 |
| PPI or H2-blocker | 45.4 | 48.8 | −0.068 | 47.0 | 47.8 | −0.018 |
| Sevelamer | 43.3 | 42.6 | 0.015 | 43.2 | 42.8 | 0.008 |
| Statin | 47.7 | 45.3 | 0.048 | 46.7 | 46.1 | 0.013 |
| History of comorbid conditions, % | ||||||
| Alcohol dependence | 0.8 | 0.8 | −0.004 | 0.8 | 0.8 | 0.001 |
| Tobacco use | 10.2 | 13.0 | −0.086 | 12.1 | 12.2 | −0.006 |
| Concomitant use of antiplatelets or NSAIDs | 15.6 | 16.0 | −0.013 | 15.8 | 15.9 | −0.002 |
| Cancer (excl. non-melanoma skin cancer) | 14.5 | 16.1 | −0.045 | 14.9 | 15.6 | −0.020 |
| Cerebrovascular disease | 18.9 | 22.6 | −0.092 | 21.0 | 21.6 | −0.015 |
| Ischemic heart disease | 63.5 | 67.5 | −0.082 | 65.9 | 66.4 | −0.010 |
| Diabetes mellitus | 68.2 | 73.0 | −0.105 | 70.7 | 71.6 | −0.020 |
| Congestive heart failure | 64.9 | 70.6 | −0.121 | 68.2 | 69.0 | −0.018 |
| Hypertension | 98.1 | 98.8 | −0.058 | 98.4 | 98.6 | −0.017 |
| Liver disease | 5.5 | 8.8 | −0.130 | 7.3 | 7.8 | −0.021 |
| Myocardial infarction | 11.4 | 17.8 | −0.180 | 14.8 | 16.0 | −0.034 |
| Peripheral vascular disease | 39.1 | 43.4 | −0.088 | 41.9 | 42.2 | −0.006 |
| Pulmonary disease | 33.3 | 37.9 | −0.098 | 35.2 | 36.6 | −0.029 |
| Stroke/TIA/TE history | 11.0 | 14.1 | −0.094 | 13.0 | 13.3 | −0.008 |
| Bleeding history | 22.5 | 32.5 | −0.224 | 27.7 | 29.6 | −0.042 |
| Risk Scores, % | ||||||
| CHA2DS2-VASc | ||||||
| Low | 0.2 | 0.2 | 0.003 | 0.2 | 0.2 | −0.003 |
| Intermediate | 18.7 | 14.3 | 0.119 | 16.3 | 15.5 | 0.021 |
| High | 81.2 | 85.6 | −0.118 | 83.5 | 84.3 | −0.021 |
| HAS-BLED | ||||||
| Intermediate | 56.3 | 46.4 | 0.199 | 51.0 | 49.3 | 0.035 |
| High | 43.7 | 53.6 | −0.199 | 49.0 | 50.7 | −0.035 |
IPTW was used to balance the observed baseline characteristics in order to account for potential confounding bias. Standardized difference was a balance assessment that compares the difference in means of the observed covariates.