Workstream 3: cost of neonatal care analysis

The cost of neonatal care for preterm babies born at 27–31 weeks gestation in England.

Sections of this chapter has reproduced with permission from Yang et al.104 This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) licence, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: https://creativecommons.org/licenses/by/4.0/. The text below includes minor additions and formatting changes to the original text.

Introduction

In this workstream, the overall cost of neonatal care (see Chapter 6), and a comparison of the cost-effectiveness of care in NICU and LNU settings (see Chapter 7), for babies born at 27–31 weeks gestation are investigated. This is an understudied cohort, and there are no correlates for cost-effectiveness analyses for very preterm births, globally. In addressing best place of care, we considered that if there were no differences in mortality and major morbidity, and there was equivalence in parental perspectives, then cost of care and cost-effectiveness of care would become important components in defining best place of care for NHS neonatal health service delivery. In this chapter we detail the overall cost burden to the NHS of initial neonatal unit care for very preterm babies and identify the key contributors to these costs.

Aim and objective

To identify, for babies born preterm at 27–31 weeks gestation and admitted to a neonatal unit in England, the overall costs of care up to neonatal unit discharge, and the main contributors to costs of care.

Methods

Study design

Retrospective analysis of resource use data recorded within the NNRD.

Data source

Data from the NNRD extract for OPTI-PREM, on preterm babies born at 27–31 weeks gestation and who were discharged from neonatal unit care or died while in neonatal care between 1 January 2014 and 31 December 2018.

Inclusion and exclusion criteria

In addition to admissions into NICU or LNU (which have resources to care for this group of very preterm babies), our cohort included babies who were inadvertently not born in maternity services colocated with LNU or NICU but were later transferred to these for continued care. Babies missing daily intervention records or for whom daily records were available, but level of care data had not been recorded, were excluded from the analysis.

Data variables

The NDAU team provided a final extraction of the relevant NNRD data fields for the cohort on 5 October 2020. Daily intervention data and treatment episode data were received in two separate data sets and were linked by means of participant identification number. Data were imported into the statistical software Stata and were manipulated such that for each baby, a daily intervention record (which included the level of care provided) was available for each day of the admission episode.

Resource use and costs

We conducted the cost analysis from the perspective of the NHS in England. We calculated the costs associated with the routine daily neonatal care received by each baby, by multiplying the number of days spent receiving each level of care, by level-specific national average bed-day costs. We sourced this from the 2018–9 National Schedule of NHS Costs.28 We derived each bed-day cost by costing the daily care items included in its corresponding neonatal critical care healthcare resource group (HRG). These are groupings of clinical activities made based on diagnosis and procedure codes. They are the ‘units’ of health care for which providers, in this case neonatal units, receive payment. HRG costs are assigned based on nationally estimated tariffs which were developed to at least cover the cost of high-quality and cost-effective care. We used the following neonatal bed-day costs: intensive care (HRG XA01Z), high-dependency care (HRG XA02Z), special care without carer resident alongside baby (HRG XA03Z), special care with carer resident alongside baby (HRG XA04Z), and normal care (HRG XA05Z). Costs are shown in Appendix 5, Table 34 and further information can be sourced within the NHS.111

The neonatal HRG does not contain all high-cost major activities. To capture high-cost specialised items, in consultation with clinical experts we selected the top five major cost non-routine procedures captured within the NNRD offered to our cohort. These were surfactant replacement therapy, utility of nitric oxide, use of total parental nutrition (TPN) (more than 14 days), palivizumab and surgical care. We identified types of neonatal surgery from corresponding operating procedure codes supplement (OPCS) and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) codes for costing purposes. We identified costs for other activities which were obtained from the published literature and through discussions with experts, as detailed in Appendix 5, Table 34. We assumed that the NNRD data for these five non-routine procedures were complete, and where there was no entry in the corresponding data set fields, we took this to mean that the procedure did not take place.

Statistical analysis

To describe neonatal and maternal characteristics, we used counts and proportions and means and SD for categorical and continuous variables respectively. We undertook all analyses of resource use data and costs by gestation in weeks at birth. We used means (SD) to summarise days provided at each level of care. We made counts of the numbers of babies for whom non-routine procedures were recorded, along with the number of cases (e.g. surgeries) or days (e.g. for nitric oxide, and TPN) for which such treatment was given. We reported total costs for the cohort and for each gestation in weeks at birth.

A secondary analysis used multiple imputations to assess routine care costs at each level (intensive care, high-dependency care, etc.) for babies with missing daily record and level of care data. An imputation model was constructed, that included complete data on baseline baby and maternal characteristics, and the total cost of care provided at each level of care (intensive care, high-dependency care, special care without carer, special care with carer and normal care). We imputed costs for each level of care for babies with missing data. Baseline characteristics included gestational age at birth, gender, number of fetuses, birthweight, neonatal death, maternal age and mode of delivery. All baseline covariates were subject to a small number of missing data that were imputed using conditional mean imputation prior to inclusion in the imputation model. A predictive mean matching estimation using chained equations with 50 imputations was implemented.112 Mean estimates and estimates of standard errors (SEs) were combined between imputed data sets using Rubin’s rule113 without any adjustment. Combined mean cost estimates and adjusted SE by gestational week across imputed data sets are shown to report the results of the multiple imputation analysis. We conducted our analyses using Stata MP.114

Results

These have been previously reported.104

We received a NNRD data extraction for 29,842 neonates. This accounted for 1,512,446 daily records and 46,746 episode (admitted to a specific unit) records. We removed babies with missing daily record information (n = 1292) and with missing data on the HRG code for daily care provided (n = 377). Our final cohort included in the cost analysis was therefore 28,173 babies (94% of the starting cohort of 29,842) (Figure 4). We included babies with congenital anomalies as they contribute to the costs of care. In Table 19 we summarise the characteristics of the babies and their mothers. When we compared between babies included in the analysis and those excluded due to missing data (n = 1669) we found that babies excluded were more likely to be born at earlier gestations (e.g. 17% vs. 12% were born at 27 weeks) (see Appendix 6, Table 35). However, the birth statistics for our cohort compared favourably to those of all very preterm babies born in England between 2016 and 2018 (data compiled by the Office for National Statistics; see Appendix 3, Table 33).

FIGURE 4 Flow of NNRD data available to estimate neonatal care costs in the OPTI-PREM cohort. (Figure not reproduced here; see the original article.)

Resource use

In Table 20 we show the mean (SD) duration of days spent receiving each level of daily care according to gestational age at birth. There was a consistent inverse relationship between gestational age at birth and the intensity of daily care provided. Figure 5 plots the mean durations along with mean overall LOS on the neonatal unit and illustrates the longer durations of higher intensity care (and indeed overall neonatal care) provided to babies born at earlier gestations. For example, babies born at 27 weeks spent on average of 18.1 days (SD = 15.7 days) receiving intensive care and 26.8 days (SD = 22 days) receiving high-dependency care, while babies born at 31 weeks received an average of 3.33 days (SD = 6.7 days) of intensive care and 5.1 days (SD = 7.5 days) of high-dependency care. Also of note is that across all gestational age at birth groups, days spent receiving special care without a carer present accounted for the largest proportion of days spent on the neonatal unit. Table 21 presents the number of babies who underwent hospital transfers and received key non-routine procedures, again by gestational age at birth. Greater resource utilisation among infants born at earlier gestations can be seen.

FIGURE 5 Mean duration vs. overall LOS by age of gestation. This figure is reproduced with permission from Yang et al.104 This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) licence, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: https://creativecommons.org/licenses/by/4.0/. The figure includes minor additions and formatting changes. (Figure not reproduced here; see the original article.)

Costs

The mean (SD) cost per baby for the various levels of care and non-routine procedures are shown by gestational age at birth in Table 22 using a complete-case analysis. As expected, and given the observations for resource use, costs can be seen to increase as gestational age at birth decreases. Mean (SD) routine daily care costs for a baby born at 27 weeks, for example, were, at £75,594 (£34,874), 2.8 times greater than the costs for a baby born at 31 weeks [£27,401 (£14,974)]. The final column in Table 22 shows that for the 2014–8 cohort, just over 50% of total costs were attributable to the provision of intensive and high-dependency care, with a further 42% coming from the provision of special care (without a carer). Further exploration of the composition of total costs in Figure 6 reveals variation by gestational age at birth. Almost 70% of total costs for babies born at 27 weeks were associated with the use of intensive and high-dependency care, while the proportion decreased to only 36% for babies born at 31 weeks. The usage, and thus cost of special care (without a carer present), increases with increasing gestational age at birth. The results of the multiple imputation analysis for the level of care costs (see Report Supplementary Material 6) were similar to the complete-case analysis. Across all gestational at birth groups, non-routine procedures accounted for only a very small proportion of total costs.

FIGURE 6 Distribution of level of care costs as a proportion of overall costs by age of gestation. This figure is reproduced with permission from Yang et al.104 This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) licence, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: https://creativecommons.org/licenses/by/4.0/. The figure includes minor additions and formatting changes. (Figure not reproduced here; see the original article.)

The overall total cost estimated for the complete-case cohort (n = 28,154) over the 5 years from 2014 to 2018 (£1.3 billion in Table 3) suggests the annual costs of neonatal care for babies born at 27 and 31 weeks gestation and admitted to a neonatal unit in England to be around £262 million, with the provision of routine daily care on these units accounting for 96% (£252 million) of overall costs. Using the overall sample of 29,842 infants would increase the total cohort costs and the estimates of annual total costs shown in Table 3 from £1,309,192,377 to £1,394,308,706 and the annual total cost from £262 million to £279 million.

Discussion

Sections of the discussion is reproduced with permission from Yang et al.104 This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) licence, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: https://creativecommons.org/licenses/by/4.0/. The text below includes minor additions and formatting changes to the original text.

Main findings

Analyses at the level of the individual baby revealed the main cost drivers to be the daily neonatal care provided to support babies. Analyses by gestational age at birth provided further evidence of the previously reported inverse relationship between resource use and healthcare costs and the degree of prematurity, with care for a baby born at 27 weeks estimated to cost almost three times more than for a baby born at 31 weeks.23 Our work also provides valuable information on the contribution of different resource components to overall costs and illustrates how the mix of intensive care required by these babies varies with gestational age at birth.

A small number of studies have previously estimated neonatal care costs for preterm babies, one of the most recent being by Rios et al.26 in Canada which also used individual patient-level resource use data from a neonatal database (the Canadian Neonatal Network Database) and included around 8000 babies born at 27 and 31 weeks gestation. A comparison between the costs estimated for the babies in this Canadian study and the costs presented here (currency conversion from Can $ to UK £ made using Purchasing Power Parities) revealed the Canadian cost estimates to be consistently lower across all gestational age groups.115 The most obvious explanation for these differences lies with the scope of the neonatal databases used by each study and the resulting implications for duration of neonatal unit stay. In general Rios et al.26 reported consistently lower mean lengths of stay for all gestational ages compared to our estimates due to their focus on intensive care units and the exclusion of the costs of care in lower dependency neonatal units. Thus, their26 estimates do not reflect the true costs of healthcare provision for this group of babies.

In 2009, Mangham et al.25 used a decision analytic model to estimate neonatal costs for a hypothetical cohort of preterm babies born in England and Wales.25 Model parameters were sourced from various cohort studies and the mean cost for a very preterm baby (< 33 weeks) was estimated to be £57,726 (95% CI 28,779 to 94,868) (2006 GBP). With that analysis using a different methodology, reporting results for a wider gestational age range, and now being well over a decade old, comparisons with the estimates reported here are challenging. While a number of more recent UK studies have been published on the costs of preterm birth, these works have focused specifically on births at other gestations (i.e. moderate and late preterm births or extremely preterm births).22,25,116 One reassuring finding however is that the costs of neonatal care for very preterm births presented here fall between the costs reported for moderate/late preterm infants and for extremely preterm infants in the UK.

Strengths and limitations

This study makes several contributions to the published literature. Firstly, existing UK cost estimates for neonatal care following very preterm birth are over a decade old and so are unlikely to reflect current standards of practice.25 This study provides up-to-date figures based on a large cohort of more than 28,000 babies who were discharged from or died within neonatal units across England between 2014 and 2018. Secondly, previous UK cost studies in the area have mainly relied on data synthesised from secondary sources to estimate costs. In utilising the NNRD, this study has been able to employ detailed and quality-assured individual participant data derived from EPRs. Furthermore, the data set offered a unique opportunity to capture near population-wide data (and thus costs) on day-to-day care provided across all neonatal units without imposing any additional burden on study participants. Thirdly, the richness of the data set permitted us not only to cost routine daily care provided at differing levels of intensity, but also to consider the cost implications of a number of major non-routine procedures, which are not captured within the HRG codes for neonatal critical care. Finally, by generating up-to-date estimates of the mean resource use and costs of neonatal care for very preterm babies in England, this study provides valuable data of interest to a range of stakeholders, including NHS managers, clinicians providing care, researchers assessing the economic implications of therapies and interventions to prevent and treat preterm birth, and decision-makers charged with implementing new policies and allocating resources.

A few limitations must also be acknowledged. This study considered only healthcare costs associated with the initial period of hospitalisation, though the economic consequences of preterm birth extend over prolonged periods of time, in some cases over the lifetime of the individual.24,25,117 Preterm birth can lead to additional health care as well as social care needs and special educational needs throughout childhood.83,118 Further research is needed to adequately capture these wider costs accurately, including the economic costs to families while their preterm baby was hospitalised, and then throughout their lives. A further limitation is the exclusion from the analysis of babies with missing data on daily care provision, who were shown to have been born at earlier gestations than babies with complete data (see Appendix 6, Table 34). While these babies accounted for only 6% of the initial NNRD cohort and data showed no differences in gestational age at birth between the babies with complete data and all very preterm births registered in England (see Report Supplementary Material 7), we observed small significant differences in baseline characteristics between babies with missing and complete data. We conducted a multiple imputation approach to understand the implications of these differences and our results suggested limited impact of the missing data in the overall cost results.

Conclusions

This study has generated up-to-date estimates of the costs of providing neonatal care to very preterm babies in England. Resource use and costs vary by gestational age at birth. The outputs from this work can be used to inform clinical and budgetary service planning and ensure the efficient allocation of healthcare resources.

Summary points from OPTI-PREM cost of care, workstream 3

What was already known prior to the study

• We do not have current cost estimates for very preterm care in England.
• These are required to inform policy-makers on most appropriate place of care for very preterm babies born at 27–31 weeks gestation.

What this study adds

• We have provided a detailed cost analysis at individual baby level, and for all very preterm babies born at 27–31 weeks gestation.
• The major costs of care are due to daily care costs.
• In England we spend approximately 0.25 billion GBP on care for preterm babies born at 27–31 weeks gestation.

How this study may affect policy

(See Chapters 9 and 10)

• This is a valuable resource to help decision-makers in resource allocation, to optimise neonatal service delivery for this cohort.
• To guide research assessing the economic implications of preventing preterm births.