Incidence of retinopathy of prematurity and background characteristics of study participants in KBTH
| Frequency (%) | Cumulative incidence (95% CI) | Child-weeks at risk | ROP cases | Incidence rate per 1000 child-weeks at risk (95% CI) | RR | Log-rank test | |
| Overall | 401 | 13.7 (10.5 to 17.5) | 14 592 | 55 | 3.8 (2.9 to 4.9) | _ | |
| LOS >4 weeks | |||||||
| No | 306 (76.3) | 4.2 (2.3 to 7.2) | 11 227 | 13 | 1.2 (0.7 to 2.0) | ||
| Yes | 95 (23.7) | 44.2 (34 to 54.8) | 3365 | 42 | 12.5 (9.2 to 16.9) | 10.8 | <0.001 |
| GA <32 weeks | |||||||
| No | 245 (61.1) | 2 (0.7 to 4.7) | 9138 | 5 | 0.5 (0.2 to 1.3) | ||
| Yes | 156 (38.9) | 32.1 (24.8 to 40) | 5454 | 50 | 9.2 (6.9 to 12.1) | 16.8 | <0.001 |
| Sex | |||||||
| Female | 222 (55.4) | 15.8 (11.2 to 21.2) | 8064 | 35 | 4.3 (3.1 to 6) | ||
| Male | 179 (44.6) | 11.2 (7 to 16.7) | 6528 | 20 | 3.1 (2 to 4.7) | 0.7 | 0.176 |
| Birth weight <1.5 kg | |||||||
| No | 223 (55.6) | 0.4 (0 to 2.5) | 8247 | 1 | 0.1 (0 to 0.9) | ||
| Yes | 178 (44.4) | 30.3 (23.7 to 37.7) | 6345 | 54 | 8.5 (6.5 to 11.1) | 70.2 | <0.001 |
| Delivery at KBTH | |||||||
| No | 80 (20) | 12.5 (6.2 to 21.8) | 2905 | 10 | 3.4 (1.9 to 6.4) | ||
| Yes | 321 (80.1) | 14 (10.4 to 18.3) | 11 687 | 45 | 3.9 (2.9 to 5.2) | 1.1 | 0.849 |
| Type of gestation | |||||||
| Single | 311 (77.6) | 12.5 (9.1 to 16.7) | 11 353 | 39 | 3.4 (2.5 to 4.7) | ||
| Multiple | 90 (22.4) | 17.8 (10.5 to 27.3) | 3239 | 16 | 4.9 (3 to 8.1) | 1.4 | 0.169 |
| Mode of delivery | |||||||
| SVD | 183 (45.6) | 17.5 (12.3 to 23.8) | 6598 | 32 | 4.8 (3.4 to 6.9) | ||
| CS | 218 (54.4) | 10.6 (6.8 to 15.4) | 7994 | 23 | 2.9 (1.9 to 4.3) | 0.6 | 0.025 |
| Small for gestation | |||||||
| No | 373 (93) | 14.2 (10.8 to 18.2) | 13 513 | 53 | 3.9 (3 to 5.1) | ||
| Yes | 28 (7) | 7.1 (0.9 to 23.5) | 1079 | 2 | 1.9 (0.5 to 7.4) | 0.5 | 0.206 |
| Blood transfusion | |||||||
| No | 365 (91) | 9.3 (6.5 to 12.8) | 13 324 | 34 | 2.6 (1.8 to 3.6) | ||
| Yes | 36 (9) | 58.3 (40.8 to 74.5) | 1268 | 21 | 16.6 (10.8 to 25.4) | 6.5 | <0.001 |
| Cardiac abnormalities | |||||||
| No | 389 (97) | 12.1 (9 to 15.7) | 14 176 | 47 | 3.3 (2.5 to 4.4) | ||
| Yes | 12 (3) | 66.7 (34.9 to 90.1) | 416 | 8 | 19.2 (9.6 to 38.5) | 5.8 | <0.001 |
| RDS | |||||||
| No | 169 (42.1) | 1.2 (0.1 to 4.2) | 6304 | 2 | 0.3 (0.1 to 1.3) | ||
| Yes | 232 (57.9) | 22.8 (17.6 to 28.8) | 8288 | 53 | 6.4 (4.9 to 8.4) | 20.2 | <0.001 |
| Premature ROM | |||||||
| No | 232 (57.9) | 10.8 (7.1 to 15.5) | 8516 | 25 | 2.9 (2 to 4.3) | ||
| Yes | 166 (41.4) | 18.1 (12.5 to 24.8) | 5966 | 30 | 5 (3.5 to 7.2) | 1.7 | 0.018 |
| Missing | 3 (0.8) | 0 (0 to 70.8) | |||||
| Pre-eclampsia | |||||||
| No | 260 (64.8) | 13.8 (9.9 to 18.7) | 9459 | 36 | 3.8 (2.7 to 5.3) | ||
| Yes | 137 (34.2) | 13.9 (8.6 to 20.8) | 4989 | 19 | 3.8 (2.4 to 6) | 1 | 0.945 |
| Missing | 4 (1) | 0 (0 to 60.2) | |||||
| Prenatal steroids | |||||||
| No | 50 (12.5) | 26 (14.6 to 40.3) | 1786 | 13 | 7.3 (4.2 to 12.5) | ||
| Yes | 136 (33.9) | 14 (8.6 to 21) | 4948 | 19 | 3.8 (2.4 to 6) | 0.5 | 0.039 |
| Missing | 215 (53.6) | 10.7 (6.9 to 15.6) | |||||
| Parity | |||||||
| Nulliparous | 136 (33.9) | 18.4 (12.3 to 25.9) | 4907 | 25 | 5.1 (3.4 to 7.5) | ||
| Multiparous | 256 (63.8) | 11.7 (8 to 16.3) | 9352 | 30 | 3.2 (2.2 to 4.6) | 0.6 | 0.067 |
| Missing | 9 (2.2) | 0 (0 to 33.6) | |||||
| Resuscitation | |||||||
| No | 42 (17.4) | 11.9 (4.0 to 25.6) | 1527 | 5 | 3.3 (1.4 to 7.9) | ||
| Yes | 38 (15.7) | 31.6 (17.5 to 48.7) | 1351 | 12 | 8.9 (5.0 to 15.6) | 2.7 | <0.001 |
| Missing | 162 (66.9) | 23.5 (17.2 to 30.7) | |||||
| Supplemental oxygen | |||||||
| No | 155 (38.7) | 0 (0 to 2.4) | 5761 | 0 | _ | ||
| Yes | 242 (60.4) | 22.7 (17.6 to 28.5) | 8687 | 55 | 6.3 (4.9 to 8.2) | _ | <0.001 |
| Missing | 4 (1) | 0 (0 to 60.2) | |||||
| Mode of oxygen delivery | |||||||
| Nasal cannula | 183 (75.6) | 19.6 (14.2 to 26.2) | 6584 | 36 | 5.5 (3.9 to 7.6) | ||
| CPAP | 49 (20.3) | 36.7 (23.4 to 51.7) | 1731 | 18 | 10.4 (6.6 to 16.5) | 1.9 | 0.009 |
| Face mask | 8 (3.3) | 0.0 (0.0 to 36.9) | 300 | 0 | |||
| Missing | 2 (0.8) | 0.5 (0.1 to 98.7) | |||||
| Monitoring SpO2 | |||||||
| Yes | 214 (88.4) | 22.0 (16.6 to 28.1) | 7662 | 47 | 6.1 (4.6 to 8.2) | ||
| No | 22 (9.1) | 22.7 (7.8 to 45.4) | 812 | 5 | 6.2 (2.6 to 14.8) | 1 | 0.714 |
| Missing | 6 (2.5) | 50.0 (11.8 to 88.2) | |||||
| Confirmed sepsis | |||||||
| No | 323 (80.6) | 8.4 (5.6 to 11.9) | 11 793 | 27 | 2.3 (1.6 to 3.3) | ||
| Yes | 74 (18.5) | 37.8 (26.8 to 49.9) | 2655 | 28 | 10.5 (7.3 to 15.3) | 4.6 | <0.001 |
| Missing | 4 (1) | 0 (0 to 60.2) | |||||
| Neonatal jaundice | |||||||
| No | 103 (25.7) | 5.8 (2.2 to 12.2) | 3805 | 6 | 1.6 (0.7 to 3.5) | ||
| Yes | 294 (73.3) | 16.7 (12.6 to 21.4) | 10 643 | 49 | 4.6 (3.5 to 6.1) | 2.9 | 0.007 |
| Missing | 4 (1) | 0 (0 to 60.2) | |||||
| Phototherapy | |||||||
| No | 107 (26.7) | 5.6 (2.1 to 11.8) | 3954 | 6 | 1.5 (0.7 to 3.4) | ||
| Yes | 290 (72.3) | 16.9 (12.8 to 21.7) | 10 494 | 49 | 4.7 (3.5 to 6.2) | 3.1 | 0.004 |
| Missing | 4 (1) | 0 (0 to 60.2) | |||||
| NG tube feeding | |||||||
| No | 252 (62.8) | 2.4 (0.9 to 5.1) | 9302 | 6 | 0.6 (0.3 to 1.4) | ||
| Yes | 144 (35.9) | 33.3 (25.7 to 41.7) | 5116 | 48 | 9.4 (7.1 to 12.5) | 14.5 | <0.001 |
| Missing | 5 (1.3) | 20 (0.5 to 71.6) | |||||
| Aminophylline | |||||||
| No | 152 (37.9) | 0.7 (0 to 3.6) | 5706 | 1 | 0.2 (0 to 1.2) | ||
| Yes | 243 (60.6) | 21.8 (16.8 to 27.5) | 8676 | 53 | 6.1 (4.7 to 8) | 34.9 | <0.001 |
| Missing | 6 (1.5) | 16.7 (0.4 to 64.1) | |||||
| Poor pupillary dilation | |||||||
| No | 388 (96.8) | 11.1 (8.1 to 14.6) | 14 147 | 43 | 3 (2.3 to 4.1) | ||
| Yes | 13 (3.2) | 92.3 (64 to 99.8) | 445 | 12 | 27 (15.3 to 47.5) | 8.9 | <0.001 |
%, percentage; CPAP, continuous positive airway pressure; CS, caesarean section; GA, gestational age; KBTH, Korle-Bu Teaching Hospital; LOS, length of stay; NG, nasogastric; RDS, respiratory distress syndrome; ROM, rupture of membranes; ROP, retinopathy of prematurity; RR, relative risk ratio; SpO2, oxygen saturation; SVD, spontaneous vaginal delivery.