Purpose: To study the association between thrombocytopenia and retinopathy of prematurity (ROP).
Methods: The case-control study was conducted on preterm newborns with ROP between January 2011 and January 2014, retrospectively. The patients were assigned into two groups: Cases required intervention and controls developed no or Stage I ROP.
Results: Eighty-one premature infants with Type I ROP were enrolled to the study with a mean gestational age of 27.6 ± 2.1 (range: 24-32) weeks and birth weight of 993 ± 292 (range: 560-1,930) g. Mean follow-up time was 38.3 ± 2.7 weeks (min: 32 and max: 46 weeks). Cases were individually matched to a set of controls (1:1 ratio). Thrombocytopenia (<150.000/mm) was seen in 58 (71.6%) of the cases with Type I ROP, whereas only 17 (21%) of the controls had thrombocytopenia (P < 0.001). Logistic regression analysis showed that bronchopulmonary dysplasia and thrombocytopenia were significantly associated with Type I ROP (relative risk [95% confidence interval]: 4.19 [1.47-12] and 6.69 [2.83-15.9], respectively). The thrombocytopenia ratio (P = 0.073), thrombocytopenia 1 week before intervention (P = 0.076) and platelet transfusion ratio (P = 0.062) tended to be higher in Zone I ROP compared with Zone II ROP.
Conclusion: In our study, there was a significant association between thrombocytopenia and Type I ROP.