Fish-Oil Fat Emulsion Supplementation May Reduce the Risk of Severe Retinopathy in VLBW Infants

Pawlik and collegues1 concluded that fish-oil-based fat emulsion administered from the first day of life to very low birthweight infants may reduce the risk of severe retinopathy of prematurity (ROP). These results seem encouraging, nevertheless to increase their reliability some methodological issues should be clarified.

The authors performed a case-control study, in which the control group was a historical cohort. Evaluating the study group, 40 cases were chosen among 63 infants admitted during a six-month period. In this group 16 infants died (the reported mortality was 25.3%), so why the remaining 7 infants were not included in the study and which were their main characteristics? Similarly, 44 of 68 eligible infants were chosen in the control group; the overall mortality was 27.9% (19 infants) so 5 more infants had to be included in the group. In other words, the authors should better explain how they matched the infants in the two groups.

Retinopathy of prematurity is a multifactorial disease characterized by abnormal retinal vascular development in which many causal factors are able to influence retinal vascularization: gestational age, birth weight, oxygen administration, bacterial or fungal infections, and blood transfusions.2 Among clinical characteristics, the authors reported the duration of both mechanical and n-CPAP ventilation but they did not report the duration of oxygen therapy. Moreover, we have no information about other risk factors for ROP such as blood transfusions and fungal infections and to show the actual effect of fish-oil on retinopathy is mandatory to know if the main risk factors of ROP are equally distributed between the study groups.

The authors also reported that the incidence of ROP stage 1 to 3 did not change in the two groups while the incidence of surgical ROP was significantly reduced in the group that received the fish-oil-based fat emulsion. How the authors explain that the fish-oil prevents only the most severe stages of ROP and not also the slightest? Have the authors used a different method for the diagnosis of ROP in the two study periods, such as the use of digital retinal camera in addition to the indirect ophthalmoscopy?

In order to encourage further investigation about the role of fish- oil-based emulsion fat in the prevention of ROP, even where the incidence of surgical ROP is not as high3 as that reported by the authors, all methodological issues must be clarified.

REFERENCES

1. Pawlik D, Lauterbach R, Turyk E. Fish-Oil Fat Emulsion Supplementation May Reduce the Risk of Severe Retinopathy in VLBW Infants. Pediatrics 2011;127:223-228.

2. Romagnoli C. Risk factors and growth factors in ROP. Early Hum Dev 2009; 85:S79-82.

3. Giannantonio C, Papacci P, Molle F, Lepore D, Gallini F, Romagnoli C. An epidemiologic analysis of retinopathy of prematurity over 10 years. J Pediatr Ophthalmol Strabismus 2008;45:162–167.

Conflict of Interest:

None declared