The incidence and mortality for meningococcal disease associated with area deprivation: an ecological study of hospital episode statistics

Aims: To determine whether incidence, mortality, and case fatality for meningococcal disease ( MD) differs by area deprivation, and if this has changed over time. Methods: The population of children aged less than 5 years with MD was analysed as quintiles of area deprivation scores over two time periods, 1995-99 and 1991-94. Annual age standardised rates were calculated and the association between incidence, mortality, and area deprivation quintiles assessed using Poisson regression and the risk ratios determined. Case fatality was calculated from the odds ratio of mortality by area deprivation score for the two time periods. Results: There were 10 524 cases of MD and 441 deaths (4.2%). Incidence rates were higher for 1995-99 (45.4 per 100000) compared to 1991-94 (27.4 per 100000). Mortality rates remained stable over time, indicating a decline in risk of death of around 40%. The incidence rates for the most deprived quintile were around twice those for the most affluent quintile, but this gradient declined over time. A threefold gradient was seen for mortality rates across the top and bottom quintiles, which was constant over time. The odds of mortality did not show a linear pattern, with mortality being lowest in the first and highest in the second and fifth area deprivation quintiles. Conclusions: These data show that MD incidence and mortality are socially patterned. The determinants of case fatality are more complex and require further investigation.