Background A lack of evidence exists concerning policies that are most likely to decrease health inequalities at condition-level and across the wider population. The National Health Inequalities Strategy (NHIS) was a cross-governmental strategy conducted in England between 1999 and 2010. This study aims to assess the extent to which the NHIS coincided with changes in inequalities of years of life lost (YLLs) and mortality amongst individual conditions and the wider population using the slope of index inequality (SII).

Methods Using Global Burden of Disease (GBD) data, age-standardised YLL and mortality rates per 100,000 were extracted for 150 Upper Tier Local Authority (UTLA) regions in England for every year between 1990–2019. Whole-population data and data for 14 individual conditions (COPD, Chronic liver diseases, Diabetes, Drug use disorders, Ischemic heart disease, Lower respiratory infections, preterm birth, Self-harm, Stroke and five categories of cancer) were collected. Linear regression models based on 2004 IMD ranks calculated the SII for each year using YLL and mortality rates for all causes and individual conditions. Joinpoint regression assessed any statistically significant changes in trends of health inequalities that arose before, during or after the NHIS.

Results Absolute inequalities in YLL for all causes remained stable between 1990 (SII=-596.06, SE=26.34) and 2000 (SII=-592.87, SE=22.89). Inequalities narrowed between 2000 and 2010 (SII=-393.78, SE=26.39). After 2010, improvements slowed (2019 SII=-370.48 (SE=28.79)). Joinpoint regression analysis found two statistically significant changes: one in 1999 (Slope Change=-0.764, 95%CI=1997–2001), and the second detected in 2013 (Slope Change=0.453, 95%CI=2009–2015). Measures of absolute inequalities for all-cause mortality showed similar patterns (1990:SII=-21.45, SE=1.14; 2000: SII=-22.51, SE=0.97; 2010:SII=-17.23, SE=1.10; 2019:SII=-15.34, SE=1.27). Joinpoint regression analysis supported these findings, with the first significant change in 1999 (Slope Change=-0.825, 95%CI=1997–2001), and the second detected in 2012 (Slope Change=0.736, 95%CI=2010–2014). The NHIS coincided with significant reductions in inequalities in YLLs and mortality due to ischemic heart disease and lung cancer.

Conclusion The findings show that the NHIS coincided with a reduction in health inequalities, and shed light on how inequalities changed amongst individual conditions throughout this time. The lack of a robust counterfactual makes it challenging to separate the impact of the strategy from that of co-occurring factors. Nevertheless, the strategy’s wide-ranging nature allows many of these factors to be considered a part of it rather than as confounders. Policymakers should consider a new cross-government strategy to tackle health inequalities drawing from the success of the previous NHIS.