Comparison with the literature

Previous studies have shown a significant proportion of excess UK mortality to result from poor outcomes in younger children.2 6 10 The results shown here build on this evidence, but further demonstrate stark differences in outcomes for older children and adolescents,5 particularly among girls. UK mortality for girls aged 15–19 was found to be significantly higher than EU15+ countries for conditions accounting for around a quarter of total deaths in this age group. Adolescent girls in the UK also ranked 17th or 18th in five out of the eight NCD groups. Worryingly, total mortality has actually increased year on year since 2013 among adolescent girls aged 15–19 in the UK, and is plateauing among adolescent boys, in contrast to the EU15+ median, which is continuing to improve (data not shown).

NCD causes appear to be a major contributor to higher than expected CYP mortality in the UK.4 5 10 11 Similar to our findings, Viner et al 4 found the UK to have higher CYP mortality than the EU15+ for endocrine, respiratory, digestive, and particularly neuropsychiatric causes (epilepsy, cerebral palsy and substance misuse). In our analysis, UK mortality for neurological causes (predominantly epilepsy) was significantly higher among adolescent girls, with around twice the number of deaths in the UK compared with the EU15+ average. The UK also ranked 17th out of 18 countries for neurological conditions among adolescents aged 15–19 years old in both sexes. UK outcomes from chronic respiratory conditions, of which the majority were deaths due to asthma, were significantly worse among boys and girls aged 5–14. UK mortality for asthma in CYP has previously been shown to be up to 11 times higher than comparable countries,11 and these differences persist after adjustment for variation in prevalence.12 Although we also found mortality for digestive conditions and DUBE to be significantly higher in the UK than in EU15+ in girls aged 15–19, both of these cause groups contain a wide range of level 3 causes, and so these results are difficult to interpret.

These findings also highlight the contribution of communicable diseases to excess mortality among CYP. Similar to our findings, Tambe et al 10 11 found higher CYP mortality rates for infections in the UK compared with Sweden and others have shown poor UK outcomes and slow rates of decline for childhood infections such as pneumonia and meningococcal disease.12–15 We found the UK to have significantly higher mortality for common infections than the EU15+ in children aged 1–9 years old (both sexes), boys aged 10–14 and girls aged 15–19, and ranked in the bottom three countries across all age groups and both sexes. Although common infections account for a relatively small proportion of total CYP deaths, reducing UK mortality to the EU15+ median would save around 85 lives a year in those aged 1–19 years old (see online supplementary material).

The UK has historically performed well in injury mortality compared with other high-income nations.4 Our findings support this, showing significantly lower mortality for transport injuries among boys aged 15–19, which account for around 21% of all injury-related deaths in those aged 1–19. We also found the UK mortality rank for most causes of death due to injury to be in the top half of countries for all age groups.

Strengths and weaknesses

We used high-quality mortality estimates provided by the WHO WMD and compared outcomes with a group of countries similar to the UK (the EU15+) used in previous benchmarking exercises.3–5 12 16 To improve comparability between countries and over time, we only included deaths coded to ICD-10, and we used the mean number of deaths and mortality rates over a 3-year period to account for large annual variability in mortality for some causes. All countries had data available within 1 year of the latest UK data release (2015), except Canada where data were available to 2013.

Differences in the way countries compile mortality statistics and whether deaths are reported by registration year or death year may have affected our results, particularly towards the end of the study period.17 The use of broad GBD level 2 cause groups reduces the risk of coding differences between countries and over time, but also has limitations due to the large number of conditions included in some groups. We considered outcomes to be significantly different if p<0.005 to account for multiple testing. We used this threshold to approximate a Bonferroni correction for 10 comparisons but maintain consistency across all age/sex groups. However, our results may have differed using alternative approaches and we may have underestimated UK excess mortality, particularly in adolescent boys. The IRRs for the number of deaths from common infections, neurological conditions and DUBE were all higher in the UK than in EU15+ among boys aged 15–19, with p<0.05 but p>0.005.

Using alternative methods to redistribute deaths may have affected our results. However, our sensitivity analysis using only appropriately coded deaths found the same pattern of mortality differences as the main analysis, with the UK having higher mortality for common infections, neurological and respiratory conditions, and good outcomes for injuries. Our results may have also been influenced by other errors in death certification. Deaths due to self-harm are known to be under-reported,18 and mortality due to common infections may be over-reported, with a large proportion potentially attributable to underlying medical conditions.2 14 19 However, as our results show excess UK mortality across a range of conditions in all age groups, they are unlikely to be fully explained by differences in coding alone.

Meaning, mechanisms and policy responses

This study aimed to identify cause-specific differences in CYP mortality in the UK compared with the EU15+. In order to explain why the UK performs poorly, we should consider the many determinants of child health and survival, how these differ between the UK and comparable countries, and what policy responses are needed to improve outcomes.

At the macro level, the social and economic environments in which CYP live are likely to be important contributors to poor health outcomes in the UK.1–3 20 A recent study found that characteristics at birth and socioeconomic factors explain over 80% of the excess all-cause mortality among children 2 days–4 years in England compared with Sweden.6 Risk factors for CYP mortality such as prematurity and low birth weight, which are strongly associated with social deprivation, are also higher in the UK than many other EU15+ countries.21 UK relative child poverty levels are higher than the best performing EU15+ countries for child mortality, and levels are predicted to increase.22 In response, the Royal College of Paediatrics and Child Health has argued that in addition to direct fiscal measures, actions to reduce the impact of poverty on child health outcomes should include a cross-government child health strategy for the UK, and developing a child-health-in-all-policies approach to reduce health and educational inequities.1 Many of the intermediate determinants of UK CYP survival are shaped by local government, and so recent reductions in funding levels, in particular spending on public health, risk impeding progress in improving mortality.23 24 At the individual level, personal, family and community conditions are strongly affected by the distal factors described above, but some may also be realised through health behaviours. Policy responses to these should be considered in the context of wider social determinants.

Our data show the UK has excess mortality for cause groups which are sensitive to healthcare improvement. For example, it is estimated that there are avoidable factors in two-thirds of UK deaths due to asthma25 and a quarter of deaths in children with epilepsy.26 Modifiable factors were also identified in 27% of deaths assessed by child death overview panels in England in 2016/2017, and has been increasing since 2012.27 UK mortality rates among children aged 1–14 for causes of death which are thought to be amenable to healthcare also appear to be higher than most countries of the Organisation for Economic Co-operation and Development.28

The NHS Long Term Plan in England,29 and similar strategies in devolved nations, offer real opportunities to modify the operation of health services to reduce the impact of social deprivation and other social determinants on child health outcomes. Improving coordination between primary and secondary care in the UK, which is worse than comparable countries,30 also has the potential to improve child health outcomes.31 This may include bringing paediatric expertise closer to the front line as the failure to recognise serious illness by health professionals not trained in paediatrics is a recurring factor in childhood deaths.32

Focusing on high burden causes would direct efforts to improve child survival where they are most needed. For example, the planned development of paediatric clinical networks for long-term conditions within the NHS Long Term Plan should focus on conditions where the UK has excess mortality.29 Investment in data systems relating to child mortality is also needed across the UK. The launch of the National Child Mortality Database for England provides a mechanism to analyse national trends in the circumstances around CYP deaths and identify patterns in modifiable factors. Establishing similar unified data systems for CYP mortality in Scotland, Wales and Northern Ireland should be a priority. Finally, continuing to monitor the UK’s progress compared with other high-income countries will provide accountability and a powerful incentive to improve outcomes.5