Elsevier

Seminars in Neonatology

Volume 9, Issue 2, April 2004, Pages 135-144
Seminars in Neonatology

Review article
Regionalized long-term follow-up

https://doi.org/10.1016/j.siny.2003.08.008Get rights and content

Abstract

The importance of population-based long-term follow-up studies of geographically determined cohorts to evaluate the effectiveness, efficiency and availability of a regionalized perinatal–neonatal care programme is demonstrated by the Victorian Infant Collaborative Study Group. The survival and quality of survival of consecutively born extremely-low-birthweight infants below 1000 g or extremely preterm infants below 28 weeks' gestation in the state of Victoria were assessed up to 14 years of age over four distinctive eras: 1979–1989, 1985–1987, 1991–1992 and 1997. Both survival and quality-adjusted survival rates rose progressively in all birth weight and gestation subgroups, associated with progressively more such infants being born in level III perinatal centres. Cost–effectiveness and cost–utility ratios remained stable overall, with efficiency gains in the smaller infants over time. Regionalized long-term follow-up provides unique information that is not available from institution-based studies, which is vital to the regional organization of perinatal–neonatal care.

Introduction

Neonatal intensive care has made impressive progress to improve the survival of the most vulnerable newborn infants. Like other high-technology and high-cost healthcare programmes that strive to save or prolong life, such as organ transplantation, its financial and emotional burden to society and to the professionals and families involved are accepted by contemporary society in most developed countries and in an increasing number of developing countries. However, neonatal intensive care programmes bring with them a responsibility for long-term follow-up to ascertain the quality of life among those who survive.

Most long-term follow-up data are based on newborn infants admitted to single centres. Although these institution-based studies are useful for the evaluation of new therapies, especially when they are conducted as randomized controlled trials, they raise the problems of selection bias and the generalizability of the findings when there is a need to see the ‘big picture’. The effectiveness of a perinatal–neonatal care programme at a regional or national level can only be determined through long-term follow-up based on a population derived from a geographically determined area.1This usually involves collaboration between many centres of different levels of care. Such multicentred collaborative studies are indispensable for the evaluation and monitoring of the survival and quality of survival of high-risk newborn infants, especially when smaller and sicker infants are treated and the limits of viability are extended to even lower gestational ages.

However, regional long-term follow-up studies remain scarce, probably because they are expensive and difficult to organize and conduct when compared with institution-based studies. This review describes the success and long track record of one such population-based project, which had its humble beginning as a two-hospital collaborative study and evolved into a total population study for a number of cohorts of high-risk births within the state of Victoria in Australia, which currently publishes under the name ‘Victorian Infant Collaborative Study Group’. It demonstrates that regional organization of long-term follow-up of a geographically determined cohort is feasible and can provide meaningful and important data, not available from institution-based studies, which are vital to the continued development of regionalized perinatal–neonatal care.

Section snippets

A need for collaborative studies

The project began with the desire to compare the effects of different physician attitudes and institutional policies regarding the perinatal and neonatal management on the outcome of very- low-birthweight infants. When the neonatal intensive care unit (NICU) at Monash Medical Centre (MMC) was first established in the 1970s with a relatively pro-active policy towards the salvage of extremely preterm infants, we initiated a collaborative study with another large NICU in Melbourne at the Royal

The importance of regionalized follow-up

The outcomes in the two tertiary university centres in the state of Victoria differed significantly. However, we knew that outside the two major institutions, there were substantial numbers of ELBW infants who were either stillborn or were born alive but not offered neonatal intensive care, and their outcomes would have been even more different. In the state of Victoria, there are three level III perinatal centres, each with its own NICU, and a fourth standalone NICU in a children's hospital.

The late 1970s ELBW cohort

The transfer of high-risk mothers to one of the three level III perinatal centres in the state of Victoria has been promoted since 1975, and NETS has been available for the transport of infants throughout the state to the four NICUs after birth since 1976. Our first regional study reported the one-year survival of 711 ELBW infants born consecutively in the state of Victoria in 1978–1981.10Although only 26% of all births in the state occurred in the three level III perinatal centres, 70% of ELBW

The mid-1980s ELBW cohort

No change in the number of extremely preterm or ELBW births occurred in the 1980s in the state of Victoria. Our regional study of the 1982–1985 cohort reported 1336 ELBW livebirths and stillbirths (5.5 per 1000 births) and 735 ELBW livebirths (3.0 per 1000 livebirths).16These figures were unchanged from those of the 1978–1981 period. However, the management of prematurity was in rapid transition. Caesarean delivery rates in the state increased from 15% to 40% for ELBW infants and from 39% to

The early 1990s ELBW cohort

A cohort of 429 ELBW infants born consecutively in the state of Victoria in 1991–1992 was compared with previous regional cohorts from 1979 to 1980 and from 1985 to 1987.22The 241 ELBW survivors were compared with 242 contemporaneous normal-birthweight controls. The two-year survival rate rose (progressively from 25% to 38% to 56% in the three cohorts). The increase in survival between 1979–1980 and 1985–1987 was primarily in infants of 750–999 g birth weight (from 37% to 57%), but the increase

The late 1990s ELBW cohort

The progressive effectiveness of neonatal intensive care over two decades was determined by a study of another regional cohort comprising 233 consecutive ELBW livebirths in the state of Victoria in 1997.25The two-year survival rate had risen progressively over the four eras: 1979–1980, 1985–1987, 1991–1992 and 1997 (Table 2). It did not exceed 50% in any 100-g birthweight subgroup in 1979–1980, whereas it did so in all subgroups in 1997. Two-year assessment was conducted in 168 ELBW children

Cohorts based on gestational age

The use of birth weight as a framework for the reporting of outcome data is a convenient system for neonatologists who have an accurate measurement on which to base the study. However, gestational age, not birth weight, is the parameter used by obstetricians as a guide to critical decisions on the management of the mother and fetus. A pro-active attitude among physicians in recent years has improved the survival prospects even among extremely preterm births of less than 26 weeks' gestation.27

The cost of improving outcome

Despite our encouraging reports of improvements over time in survival and neurosensory disability rates in ELBW children in the state of Victoria, neonatal intensive care is expensive and some would argue that resources might be better allocated to other healthcare programmes within our limited health budget. Consequently, economic evaluations of neonatal intensive care are mandatory. The incremental cost of improving the outcome for ELBW infants born in our state was determined using data from

Conclusions

The overall long-term survival of ELBW infants born in the state of Victoria has tripled over two decades, having increased eight-fold in infants of 500–699 g birth weight, quadrupled in infants of 700–799 g, and doubled in infants of 800–999 g. It is most remarkable that over 40% of infants born at 23 weeks' gestation within our geographically determined region survived in 1997. Neonatal intensive care, provided in the context of regional organization of perinatal services, has been very

References (34)

  • V.Y.H Yu et al.

    Survival prospects of extremely preterm infants: a 10-year experience in a single perinatal center

    Am J Perinatol

    (1992)
  • L.W Doyle et al.

    Accuracy of mortality rates for livebirths 500–999 g birthweight

    Med J Aust

    (1991)
  • W.H Kitchen et al.

    Provision of perinatal services and survival of extremely low birthweight infants in Victoria

    Med J Aust

    (1983)
  • W.H Kitchen et al.

    Outcome of extremely low birth-weight infants in relation to the hospital of birth

    Aust N Z J Obstet Gynaecol

    (1984)
  • Eight-year outcome in infants with birth weight 500 to 999 grams: continued regional study of 1979 and 1980 births

    J Pediatr

    (1991)
  • L.W Doyle et al.

    Outcome at 14 years of extremely low birthweight infants: a regional study

    Arch Dis Child Fetal Neonatal Ed

    (2001)
  • J Lumley et al.

    The survival of extremely-low-birthweight infants in Victoria: 1982–1985

    Med J Aust

    (1988)
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