Deprivation index and dependency ratio are key determinants of emergency medical admission rates

• Deprivation Index and Dependency Ratio predict hospital admission rate.
• Acute Illness Severity and Chronic Disabling Disease do not predict admissions.
• Deprivation Index and Dependency Ratio synergistically increase admission rate.

BackgroundPatients from deprived backgrounds have a higher in-patient mortality following an emergency medical admission; there has been debate as to the extent to which deprivation and population structure influences hospital admission rate.MethodsAll emergency medical admissions to an Irish hospital over a 12-year period (2002–2013) categorized by quintile of Deprivation Index and Dependency Ratio (proportion of population < 15 or ≥ 65 years) from small area population statistics (SAPS), were evaluated against hospital admission rates. Univariate and multivariable risk estimates (Odds Ratios (OR) or Incidence Rate Ratios (IRR)) were calculated, using logistic or zero truncated Poisson regression as appropriate.Results66,861 admissions in 36,214 patients occured during the study period. The Deprivation Index quintile independently predicted the admission rate/1000 population, Q1 9.4 (95%CI 9.2 to 9.7), Q2 16.8 (95%CI 16.6 to 17.0), Q3 33.8 (95%CI 33.5 to 34.1), Q4 29.6 (95%CI 29.3 to 29.8) and Q5 45.4 (95%CI 44.5 to 46.2). Similarly the population Dependency Ratio was an independent predictor of the admission rate with adjusted predicted rates of Q1 20.8 (95%CI 20.5 to 21.1), Q2 19.2 (95%CI 19.0 to 19.4), Q3 27.6 (95%CI 27.3 to 27.9), Q4 43.9 (95%CI 43.5 to 44.4) and Q5 34.4 (95%CI 34.1 to 34.7). A high concurrent Deprivation Index and Dependency Ratio were associated with very high admission rates.ConclusionDeprivation Index and population Dependency Ratio are key determinants of the rate of emergency medical admissions.