Purpose: To identify differences in incidence, risk factors, and outcomes of retinopathy of prematurity (ROP) between 2 birth weight categories within a cohort of extremely low birth weight (ELBW) infants in Malaysia.
Methods: This was a prospective study of infants in the Special Care Nursery at the University of Malaya Medical Centre between 2003 and 2005. Outcome measures were presence or absence of ROP, most severe stage of ROP observed, and whether laser treatment was performed. Risk factors for treatment were analyzed in this cohort of treated patients, who were further divided into groups of birth weight <751 g and birth weight 751-1,000 g.
Results: The study protocol identified 70 qualifying ELBW infants. Of these, 41 (58.6%) developed ROP and 23 (32.9%) required laser treatment. Mean birth weight was 806.8 g (SD +/- 142.5); mean gestation was 27.4 weeks (SD +/- 2.2). Infants with birth weight <750 g were twice as likely to require treatment (OR = 2, p = 0.038). The risk factors for laser treatment by bivariate analysis were gestation <28 weeks (OR = 1.8, p = 0.001), duration of ventilation >1 week (OR = 1.5, p = 0.012), and intraventricular hemorrhage (OR = 2.5, p = 0.010). Zone 1 ROP was observed only in infants <751 g.
Conclusions: The incidence of ROP in ELBW infants in Malaysia is comparable to that seen in the ETROP and CRYO-ROP studies. Within this group, birth weight <750 g doubled the likelihood that treatment would be required.