Mortality due to Rare Diseases

This atlas shows the population-based mortality due to Rare Diseases, its time trends and geographic variability.

The epidemiological information is presented as a complement to the data from existing Rare Diseases registries.

Data sources

Annual population and mortality data for Spain were obtained from National Statistics Institute (INE), according to cause of death, residence place, sex and age.

The causes of death due to Rare Diseases were selected according to ICD 10 list of the Spanish Rare Diseases Registries Research Network (SpainRDR).

Basemaps were obtained from Instituto Geográfico Nacional, Centro Nacional de Información Geográfica for municipalities, provinces and Autonomous Communities and from Ministerio de Agricultura, Pesca y Alimentación for districts.

Epidemiological Indicators

Age-adjusted Mortality Rate:

The age distribution of a population can change over time and can be different in geographic areas. The process of age-adjustment ensures that the variability in mortality rates from one year to another, or between one geographic area and another, are not due to differences in the age distribution of the populations being compared. It is a summary measure of the rates that would have existed if the population under study had the same age distribution as the "standard" population.

The following age-standardized mortality rates are calculated using direct age-adjustment method and the European standardized population as reference. They are expressed per 100,000 population.

Standardized Mortality Ratio(SMR):

SMR is a ratio between the observed number of deaths in a study population and the expected number of deaths based on the age- and sex-mortality rates in a standard population.

The following SMRs are indirect standardized rates considering the Spanish mortality rate as reference. A ratio of observed/expected deaths greater than 1.0 means there is a higher than expected mortality in that geographical unit.

Smoothed Standardized Mortality Ratio:

Smoothing procedure prevent problems arising from numerical instability in geographical units with low numbers of deaths and/or from neighbouring units with contrasting risks. SMRs were smoothed using Bayesian estimates based on the spatial hierarchical model proposed by Besag, York y Mollié.

Posterior Probability:

The posterior probability is a measure associated to smoothed standardized mortality ratios. Posterior probability values of over 0.80 show a significantly higher-than-expected mortality risk and values under 0.20 indicate a significantly lower-than-expected risk.


- Verónica Alonso Ferreira1, Principal Investigator.

- Francisco J Escobar Martínez2, University Professor.

- Germán Sánchez Díaz1,2, Junior Researcher.

- Manuel Posada de la Paz1, Director.

1 Instituto de Investigación de Enfermedades Raras, Instituto de Salud Carlos III.

2 Departamento de Geología, Geografía y Medio Ambiente, Universidad de Alcalá.

Funding: Instituto de Salud Carlos III, AESI project no. TPY 1238/15.