Table A1.
Covariate balance analyses in propensity matched samples for patients with biological vs. mechanical valve prostheses.
| Variable | Type | Unadjusted Sample | Adjusted Sample | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Biological Valve 281 pts |
Mechanical Valve 268 pts |
Balance Measures | Biological Valve 281 pts |
Mechanical Valve 268 pts |
Balance Measures | ||||||||||
| Mean | Standard Deviation | Mean | Standard Deviation | Mean Difference |
Variance Ratio | KS | Mean | Standard Deviation | Mean | Standard Deviation | Mean Difference | Variance Ratio | KS | ||
| Distance | 0.4302 | 0.1604 | 0.5489 | 0.1602 | 0.7407 | 0.9974 | 0.3320 | 0.5471 | 0.1577 | 0.5489 | 0.1602 | 0.0109 | 1.0319 | 0.0448 | |
| Age | Contin. | 55.2723 | 7.3493 | 51.7304 | 7.1413 | −0.4960 | 0.9442 | 0.2355 | 51.2162 | 7.1479 | 51.7304 | 7.1413 | 0.0720 | 0.9982 | 0.1008 |
| Female gender | Binary | 0.1423 | . | 0.2388 | . | 0.0965 | . | 0.0965 | 0.2397 | . | 0.2388 | . | −0.0009 | . | 0.0009 |
| S. aureus | Binary | 0.1459 | . | 0.1269 | . | -0.0190 | . | 0.0190 | 0.1712 | . | 0.1269 | . | −0.0443 | . | 0.0443 |
| Hypertension | Binary | 0.2669 | . | 0.2388 | . | −0.0281 | . | 0.0281 | 0.2618 | . | 0.2388 | . | −0.0230 | . | 0.0230 |
| Diabetes | Binary | 0.1139 | . | 0.0858 | . | −0.0281 | . | 0.0281 | 0.0898 | . | 0.0858 | . | −0.0040 | . | 0.0040 |
| Obesity | Binary | 0.0783 | . | 0.0672 | . | −0.0111 | . | 0.0111 | 0.0805 | . | 0.0672 | . | −0.0133 | . | 0.0133 |
| COPD | Binary | 0.0569 | . | 0.0485 | . | −0.0084 | . | 0.0084 | 0.0483 | . | 0.0485 | . | 0.0002 | . | 0.0002 |
| LVEF | Contin. | 54.2206 | 9.4673 | 54.9440 | 8.4539 | 0.0856 | 0.7974 | 0.0925 | 54.4560 | 9.6088 | 54.9440 | 8.4539 | 0.0577 | 0.7741 | 0.0726 |
| Drug abuse | Binary | 0.0463 | . | 0.0522 | . | 0.0060 | . | 0.0060 | 0.0441 | . | 0.0522 | . | 0.0082 | . | 0.0082 |
| Previous cardiac operation | Binary | 0.0498 | . | 0.0299 | . | −0.0200 | . | 0.0200 | 0.0252 | . | 0.0299 | . | 0.0046 | . | 0.0046 |
| IABP | Binary | 0.0178 | . | 0.0037 | . | −0.0141 | . | 0.0141 | 0.0083 | . | 0.0037 | . | −0.0045 | . | 0.0045 |
| Peripheral artery disease | Binary | 0.0463 | . | 0.0299 | . | −0.0164 | . | 0.0164 | 0.0386 | . | 0.0299 | . | −0.0087 | . | 0.0087 |
| Preoperative stroke | Binary | 0.1210 | . | 0.1119 | . | −0.0091 | . | 0.0091 | 0.1172 | . | 0.1119 | . | −0.0052 | . | 0.0052 |
| Cardiogenic shock | Binary | 0.0961 | . | 0.0485 | . | −0.0476 | . | 0.0476 | 0.0920 | . | 0.0485 | . | −0.0434 | . | 0.0434 |
| AMI | Binary | 0.0142 | . | 0.0112 | . | −0.0030 | . | 0.0030 | 0.0270 | . | 0.0112 | . | −0.0158 | . | 0.0158 |
| Active endocarditis | Binary | 0.8043 | . | 0.7649 | . | −0.0393 | . | 0.0393 | 0.8177 | . | 0.7649 | . | −0.0527 | . | 0.0527 |
| Preoperative MV | Binary | 0.0996 | . | 0.0299 | . | −0.0698 | . | 0.0698 | 0.0611 | . | 0.0299 | . | −0.0312 | . | 0.0312 |
| Pulmonary hypertension | Binary | 0.0676 | . | 0.0560 | . | −0.0116 | . | 0.0116 | 0.0526 | . | 0.0560 | . | 0.0034 | . | 0.0034 |
| CKD | Binary | 0.0996 | . | 0.0970 | . | −0.0026 | . | 0.0026 | 0.0980 | . | 0.0970 | . | −0.0010 | . | 0.0010 |
| Abscess | Binary | 0.1530 | . | 0.1007 | . | −0.0523 | . | 0.0523 | 0.1016 | . | 0.1007 | . | −0.0009 | . | 0.0009 |
AMI, acute myocardial infarction; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; IABP, intra-aortic balloon pump; KS, Kolmogorov–Smirnov test; LVEF, left ventricular ejection fraction; MV, mechanical ventilation. For further information on balance measures, see the reference: Austin PC, Stuart EA. Moving towards best practice when using inverse probability of treatment weighting (IPTW) using the propensity score to estimate causal treatment effects in observational studies [32].