[Incidence and risk factors of retinopathy of prematurity in University Hospital Onofre Lopes, Natal (RN)-Brazil].

PURPOSES: To determine the incidence of retinopathy of prematurity and assess the main risk factors involved in its development.

METHODS

Retrospective cohort study carried out from January 2004 to December 2006, at University Hospital Onofre Lopes, Natal (RN)-Brazil. The sample was composed of 663 newborns, with less than or equal to 36 weeks of gestational age and/or birth weight less than or equal to 1,500 g, submitted to the protocol of retinopathy of prematurity in the ophthalmology department of the hospital. The variables were: gender, birth weight, gestational age, duration of oxygen therapy, mechanical ventilation, sepsis and blood transfusion. Data were analyzed through the chi-squared test, Fisher's exact test and logistic regression model.

RESULTS

Of the 663 cases, retinopathy of prematurity occurred in 414 (62.4%). Of the total sample, 338 (51.0%) were male and 282 (42.5%) female. Mean and standard deviation of weight, gestational age and duration of oxygen therapy were, respectively, 1,334.9+/-345.6 g, 31.9+/-2.3 weeks and 10.0+/-14.0 days. The incidence of retinopathy in premature newborns in the period was 62.4%, 58.0% of cases in 2004, 67.2% in 2005 and 63.0% in 2006. The multiple logistic regression analysis showed that the weight less than 1,000 g (p<0.001; adjOR=17.18, CI=6.52-45.29) and between 1,000 g and 1,500 g (p=0.002; adjOR -4.20 CI=1.68-10.48), the time of oxygen lounger than 20 days (p=0.022; adjOR=3.40, CI=1.19-9.69) and blood transfusion (p=0.022; adjOR -2.06, CI=1.11-3.83) are independent factors for the disease.

CONCLUSIONS

The study showed a high incidence of the disease in the service. A low birth weight, a prolonged oxygen therapy and blood transfusion are factors associated with the development of retinopathy of prematurity. Gestational age is not a reliable parameter for screening of newborns in the service.