Socioeconomic Status and Economic Burden of Pertussis in Adults: Post-Hoc Analyses of a Retrospective Database Study in England

OBJECTIVES: Pertussis is under-recognized in older adults, and few studies have explored the impact of socio-economic status on the pertussis economic burden. We aimed to estimate the economic burden of pertussis among ≥50-year-olds in England, from 2009 to 2018, stratified by index of multiple deprivation (IMD).

METHODS: In this post-hoc sub-analysis on retrospective observational study data of the Clinical Practice Research Datalink and the Hospital Episode Statistics databases, we used IMD as a proxy to classify socioeconomic status from least to most deprived (quintiles 1 to 5). Healthcare resource utilization (HCRU) and direct medical costs (DMC) were compared between patients with pertussis and propensity score-matched controls at distinct time points before and after diagnosis. Costs were adjusted for inflation.

RESULTS: A total of 1,479 patients with pertussis were included in the analysis. Most patients (n=561) belonged to the least deprived quintile (IMD Q1). The number of patients decreased with socio-economic status: Q2 n=358; Q3 n=286; Q4 n=167; Q5 n=107. For all IMD quintiles, the HCRU and DMC were higher in the pertussis cohort compared to controls. The total annualized cost per patient tended to increase with IMD quintile: Q1 246.0£ (95% confidence interval [CI]: 54.8 – 469.0); Q2 385.3£ (160.0 – 654.2); Q3 468.9£ (178.1 – 823.1); Q4 668.4£ (339.2 – 1,085.3); Q5 462.5£ (15.7 – 1,064.2). A similar trend was observed for the percentage difference, ranging from 22.0% (95% CI: 4.9 – 41.9) for the least deprived population (Q1) to 74.7% (37.9 – 121.3) for the second most deprived (Q4).

CONCLUSIONS: Pertussis economic burden was detected in all IMD categories and tended to increase with IMD quintile. Further research is needed to investigate the link between IMD status and pertussis economic burden.