Patient Characteristics
| Characteristic | Test value | P | Caffeine consumers | Non–caffeine consumers |
| Mean age | t = 1.299 | 0.1970 | 63.39 (12.34) | 58.00 (17.77) |
| β-blocker use | χ2 = 0.785 | 0.3757 | 41% | 27% |
| Diabetes | χ2 = 0.323 | 0.5701 | 37% | 45% |
| Sex | χ2 = 3.404 | 0.0650 | 57% M | 27% M |
| Mean body weight (kg) | t = 1.264 | 0.2093 | 85.30 (19.03) | 92.99 (19.23) |
| Mean body mass index | t = 2.041 | 0.0439 | 29.40 (6.62) | 33.69 (6.21) |
| Coronary artery disease | χ2 = 0.068 | 0.7944 | 31% | 27% |
| Hypertension | χ2 = 0.157 | 0.6916 | 87% | 91% |
| Hyperlipidemia | χ2 = 3.562 | 0.0591 | 62% | 91% |
| Smoker | χ2 = 0.764 | 0.3821 | 20% | 9% |
Data in parentheses are SDs.