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Metadata and methodology

Metadata are 'data about data', that is, the definitional and descriptive information that makes numbers meaningful. 

A good example of metadata in the context of cystic fibrosis patient registries is the material published in Appendix 1 and Appendix 2 of the ECFS Patient Registry Annual Data Report 2008-2009 Data.  These appendixes specify the data that are expected to be contributed to the ECFSPR by national CF registries and CF centres.  Few, if any, national registries publish as much detail about the data that they publish in annual reports.  Users of the data are therefore needing more information to assist them to interpret the information for their intended use, especially where comparative data across national registries are involved.

A development objective for this website is to gather as much metadata and methodology material as is available from CF patient registries and, in doing so, to encourage publication of more of this material in association with their annual data reports.

Internationally comparable CF data

There has been no agreement on standards or presentation formats for CF data.  The following is a suggestion by the website coordinator for statistics that would be high priority and may be expected to be available from most national CF registries.

Demography

Table of population by sex (male, female and total) and age groups, as follows: 

  1. For standard demographic comparisons: 
    5 year age groups 0-4, 5-9, ... , 55-59, 60+, total
  2. Denominators/reference populations for CF-specific indicators:
     Age groups 0-1, 2-5, 6-11, 12-18, total 0-18 years, 18-29, 30+, total 18+, as described in Sims (2009).

Median age by sex (male, female and total)
Proportion of CF population who are adult (aged 18 years and over)

Diagnosis

Number of new diagnoses in current year

Percent of new cases diagnosed by newborn screening (current year)

Median age at diagnosis:

  1. For current year diagnoses
  2. For all patients in registry

Genotype

Number and per cent of registry population who are:

  1.  F508del homozygotes
  2.  F508del heterozygotes
  3.  Others with identified genotypes
  4.  Not genotyped or missing genotype data

Lung function

Table of median FEV1 per cent of predicted (specify source of predicted values*) by sex and age (according to demography option 2, excluding 0-5 years), excluding patients with lung transplants.

* where possible, predicted values published by Wang et al (1993) should be used for males aged 6-17 years and females aged 6-15 years and values from Hankinson et al (1999) for older persons.

Growth/nutrition

 Table of median body mass index (BMI) percentiles (specify source of reference values*) by sex and child/adolescent age groups within demography option 2 (see above).

Table of BMI by sex and adult age groups within demography option 2 (see above)

* where possible use CDC 2000 series growth charts described in Kuczmarski et al (2002)

Mortality

Number of deaths within current year, by sex (male, female, total)

Median age at death for deaths within current year, by sex (male, female, total)

References

Sims G. International benchmarking for cystic fibrosis outcomes using registry data.   Poster at European Cystic Fibrosis Conference, Brest, July 2009.

Sims G. ECFS 2009 Poster Sims G. ECFS 2009 Poster (709 KB)

Wang X, Dockery DW, Wypij D, Fay ME, Ferris BG. Pulmonary function between 6 and 18 years of age.   Pediatr Pulmonol 1993;15:75-88.

Hankinson JL, Odencrantz RJ, Fedan KB. Spirometric reference values from a sample of the general U.S. population. Am J Respr Crit Care Med 1999;159:179-87.

Kuczmarski RJ, Ogden CL, Guo SS et al.   2000 CDC growth charts for the United States: Methods and development. National Center for Health Statistics.   Vital Health Stat 2002; 11(246):1-190.