[No increase of incidence of retinopathy of prematurity and improvement of its outcome in a university perinatal centre level III - a prospective observational study from 1978 to 2007].

BACKGROUND

There is a controversy over whether the improved survival rate of extremely low birth weight (ELBW; birth weight < 1000 g) and of extremely low gestational age (ELGA; gestational age < 28 weeks) infants has resulted in a higher incidence of severe retinopathy of prematurity (ROP) and induced blindness. We studied the incidence, treatment and the structural outcome of ROP in a Perinatal Centre Level III over a 30-year period in infants < 1500 g birth weight (VLBW = very low birth weight).

PATIENTS AND

METHODS

1473 VLBW infants, who survived the first 28 days, had ocular examinations from 1978 to 2007. Neonatal and ROP data were collected prospectively. Proliferative ROP, threshold disease and high-risk prethreshold ROP indicated treatment for peripheral retinal ablation in respect to the CRYO-ROP and ETROP studies. Incidence, treatment and structural outcome of ROP were analysed for the periods 1978 - 1992 (P1) and 1993 - 2007 (P2) and for children with BW < 1000 g and > 1000 g.

RESULTS

In P 1 43.1 % (n = 87) ELBW infants survived and 82.3 % (n = 372) in P 2, whereas the survival rates of the infants with a BW of 1000 - 1499 g were 74.6 % (n = 453) and 95.1 % (561), respectively. The ROP incidence was decreased from 27.6 % (n = 149) in P 1 to 15.1 % (n = 141) in P 2 significantly (p < 0.003) as well the mean BW 1136.6 ± 211.3 g to a mean BW 822.3 ± 215.3 g and the mean gestational age (GA) 29.3 ± 2.2 weeks and to a mean GA 26.4 ± 2 weeks, respectively (both differences p < 0.001). Also the coagulation rate was significantly decreased from 13 % (n = 70) in P 1 to 6.8 % (n = 63) in P 2 (p = 0.043). The blindness rates (structurally unfavourable outcome of both eyes) of 1.5 % in P 1 and 1.0 % in P 2 were not significantly reduced (p = 0.543). Among the ELBW the number of ROP infants was increased from 39 in P 1 to 117 in P 2 while the ROP incidence decreased from 44.8 % to 31.5 % (p = 0.053) and the ROP-OP rate from 19.5 % to 14.8 % (p = 0.029). Also among the ELGA the number ROP infants was increased from 66 in P 1 to 121 in P 2 but the ROP incidence was reduced from 70.2 % to 27.6 % and the ROP-OP rate from 30.9 % to 13.2 % (both p < 0.001).

CONCLUSIONS

Inspite of an increase of the number of ELBW/ELGA infants and their survival rate in 1978 - 2007 there is no increase in the incidence of ROP, operations and blindness among the VLBW and VLGA infants.