Table 2. PCR result and ECG findings at the follow-up visit among T. cruzi-seropositive blood donors.
| Disease parameters | Reduction in S/CO > 1 n = 56 | Reduction of S/CO < 1 or increase n = 197 | p-value | Follow-up S/CO < 4 n = 35 | Follow-up S/CO ≥ 4 n = 241 | p-value | Donation S/CO < 4 n = 19 | Donation S/CO ≥ 4 n = 234 | p-value |
|---|---|---|---|---|---|---|---|---|---|
| PCR result | |||||||||
| Positive | 15 (26.8) | 104 (52.8) | 6 (17.1) | 125 (51.9) | 3 (15.8) | 116 (49.6) | |||
| Negative | 41 (73.2) | 93 (47.2) | 0.001 | 29 (82.9) | 116 (48.1) | <0.001 | 16 (84.2) | 118 (50.4) | 0.009 |
| Final ECG classification, n (%) | |||||||||
| Major | 11 (19.6) | 76 (38.6) | 4 (11.4) | 94 (39.0) | 1 (5.3) | 86 (36.8) | |||
| Minor | 29 (51.8) | 82 (41.6) | 19 (54.3) | 101 (41.9) | 12 (63.2) | 99 (42.3) | |||
| Normal | 16 (28.6) | 39 (19.7) | 0.028 | 12 (34.3) | 46 (19.1) | 0.004 | 6 (31.6) | 49 (20.9) | 0.010 |
| Typical changes, n (%) | |||||||||
| 0 | 46 (82.1) | 122 (61.9) | 31 (88.6) | 149 (61.8) | 18 (94.7) | 150 (64.1) | |||
| 1 | 6 (10.7) | 57 (28.9) | 3 (8.6) | 67 (27.8) | 0 (0) | 63 (26.9) | |||
| 2+ | 4 (7.1) | 18 (9.1) | 0.010 | 1 (2.9) | 25 (10.4) | 0.006 | 1 (5.3) | 21 (9.0) | 0.009 |
| Joint PCR/ECG endpoint, n(%) | |||||||||
| PCR-ve & ECG normal | 36 (64.3) | 62 (31.5) | 25 (71.4) | 80 (33.2) | 15 (78.9) | 83 (35.5) | |||
| PCR+ve &/or ECG abnormal | 20 (35.7) | 135 (68.5) | <0.001 | 10 (28.6) | 161 (66.8) | <0.001 | 4 (21.1) | 151 (64.5) | <0.001 |
PCR–polymerase chain reaction; ECG–electrocardiogram. Final ECG classification: major if at least one major alteration, minor if only minor alterations present, normal if neither minor nor major alterations present. Typical ECG changes refer to alterations typical of Chagas cardiomyopathy following the 2nd Brazilian consensus on Chagas disease. P-values are calculated by Chi-squared test or Wilcoxon rank sum, as appropriate.