Table 1.
Characteristics of patients in the study
| Variable | Statistic | Congenital Heart Disease Requiring Surgery | Controls | Standardized Difference |
|---|---|---|---|---|
| n=3600 | n=36,000 | |||
| Demographics | ||||
| Age, yr, median (IQR) | 0.41 (0.11–0.69) | 0.41 (0.12–0.68) | ||
| Female | 1595 (44%) | 15,950 (44%) | 0% | |
| Rural residence | 386 (11%) | 3860 (11%) | 0% | |
| Income quintile | 1 (lowest) | 790 (22%) | 7900 (22%) | 0% |
| 2 | 721 (20%) | 7210 (20%) | 0% | |
| 3 | 751 (21%) | 7510 (21%) | 0% | |
| 4 | 765 (21%) | 7650 (21%) | 0% | |
| 5 (highest) | 573 (16%) | 5730 (16%) | 0% | |
| Year of surgery (reference date for normal) | 2002–2004 | 566 (16%) | 5652 (16%) | 0% |
| 2005–2007 | 781 (22%) | 7827 (22%) | 0% | |
| 2008–2010 | 958 (27%) | 9579 (27%) | 0% | |
| 2011–2013 | 931 (26%) | 9310 (26%) | 0% | |
| 2014–2015 | 364 (10%) | 3632 (10%) | 0% | |
| Maternal age, yr, median (IQR) | 32 (28–36) | 31 (27–35) | ||
| Gestational age, wk | Mean (SD) | 38 (2.42) | 38.9 (2.07) | 94% |
| Median (IQR) | 38(37–40) | 39 (38–40) | ||
| Preterm (<37 wk) | 652 (18%) | 2694 (8%) | 76% | |
| Very preterm (<32 wk) | 98 (3%) | 263 (1%) | 36% | |
| Extremely preterm (<28 wk) | 29 (1%) | 67 (0.2%) | 21% | |
| Birth weight, g | Mean (SD) | 3066 (711) | 3377 (556) | 115% |
| Median (IQR) | 3140 (2670–3532) | 3400 (3053–3730) | ||
| Low birth weight (<2500 g) | 681 (19%) | 2042 (6%) | 97% | |
| Very low birth weight (<1500 g) | 104 (3%) | 171 (1%) | 44% | |
| Hypertension | 72 (2%) | 80 (0.2%) | 17% | |
| CKD | 10 (0.3%) | 16 (0%) | 8% | |
| Chromosomal anomaly | 470 (13%) | 22 (0.1%) | 54% | |
| Multibirth | Yes | 190 (5%) | 1074 (3%) | 12% |
| Surgery hospitalization characteristics | ||||
| Any congenital heart disease diagnosis | 3600 (100%) | |||
| Severe congenital heart disease diagnosis | 1866 (52%) | |||
| Risk Adjustment for Congenital Heart Surgery-1 (RACHS-1) score | 1 | 424 (12%) | ||
| 2 | 1598 (44%) | |||
| 3 | 1051 (29%) | |||
| ≥4 | 519 (14%) | |||
| Length of stay in hospital, d | Mean (SD) | 24.7 (66.8) | ||
| Median (IQR) | 10 (5–23) | |||
| Length of stay in hospital after surgery, d (surgery date to discharge date) | Mean (SD) | 19.7 (63.3) | ||
| Median (IQR) | 8 (5–17) | |||
| Length of stay in ICU, d | Mean (SD) | 11.7 (25.0) | ||
| Median (IQR) | 5 (2–11) | |||
| Time on ventilation, d | Mean (SD) | 9.3 (20.7) | ||
| Median (IQR) | 4 (2–9) | |||
| Dialysis during index hospitalization | 126 (4%) | |||
IQR, interquartile range; ICU, intensive care unit.