Estimation of contribution of changes in coronary care to improving survival, event rates and coronary heart disease mortality across the WHO MONICA Project populations: appendix to a paper published in the Lancet

Definitions of case fatality for coronary events in the WHO MONICA Project

February 2000

Markku Mähönen¹, Hugh Tunstall-Pedoe², Anna-Maija Rajakangas¹, Zygimantas Cepaitis¹, Kari Kuulasmaa¹, Annette Dobson ³ and Ulrich Keil⁴  for the WHO MONICA Project⁵

¹ Department of Epidemiology and Health Promotion (MONICA Data Centre), National Public Health Institute, KTL, Helsinki, Finland
²Cardiovascular Epidemiology Unit, (MONICA Quality Control Centre for Event Registration), University of Dundee, Ninewells Hospital and Medical School, Dundee, Scotland, U.K.
³ Department of Statistics, University of Newcastle, New South Wales, Australia
⁴Department of Epidemiology and Social Medicine, University of Münster, Münster, Germany
⁵ Annex: Sites and key personnel of the WHO MONICA Project

Correspondence to: markku.mahonen@ktl.fi

• Copyright notice
• Document identification:
  • WHO MONICA Project e-publications (ISSN 2242-1246), No. 21.2
  • URL:http://www.thl.fi/publications/monica/carpfish/appendd/cfdef.htm
  • URN:NBN:fi-fe976570

Contents

• 1. Introduction
• 2. Definitions of case fatality
• References
• Acknowledgements

1. Introduction

The purpose of this paper is to document the details of the definitions of case fatality that were used in WHO MONICA Project's publications on population versus clinical view of case fatality from acute coronary heart disease [1] and estimation of contribution of changes in coronary care to improving survival, event rates and coronary heart disease mortality [2].

2. Definitions of case fatality

The terms SURVIV (survival status), DIACAT (diagnostic category), DONSET (date of onset), DBIRTH (date of birth), PREMI (previous histoty of myogardial infarction), MANAGE (management) and ESTST (estimated survival time) are names of MONICA data items, and have been defined in the Core data transfer format - coronary events in the MONICA Manual [3].

Definitions of variables needed for the definitions of case fatality:

F1:

number of events with SURVIV=2 and DIACAT=1

F2:

number of events with SURVIV=2 and DIACAT=2

F9:

number of events with SURVIV=2 and DIACAT=9

NF1:

number of events with SURVIV=1 or 9 and DIACAT=1

FHOSP (fatal hospitalized):

number of events with SURVIV=2 and MANAGE=1

FPRE (fatal pre-hospital):

number of events with SURVIV=2 and MANAGE=2, 3, 4, 5 or 9

NFHOSP (non-fatal hospitalized):

number of events with SURVIV=1 or 9 and MANAGE=1

FIN24 (died within 24 hours):

number of events with SURVIV= 2 and MANAGE=1 and ESTST= 1, 2, 4 or 9

FMORE24 (survived 24 h, but died before 28th day):

number of events with SURVIV=2 and MANAGE=1 and ESTST= 3 or 5

Definitions of case fatality (CF):

28-day CF:

(F1+F2+F9) /( F1+F2+F9+NF1)

Pre-hospital CF:

FPRE / (F1+F2+F9+NF1)

28-day CF for hospitalized events:

FHOSP /(FHOSP+NFHOSP)

Residual hospital-related CF:

FHOSP/(F1+F2+F9+NF1)

28-day CF for hospitalized 24-hour survivors:

FMORE24/(FMORE24+NFHOSP)

24-hour CF:

(FIN24+FPRE)/(FIN24+FPRE+FMORE24+NF1)

Note:

• 28-day CF = Pre-hospital CF   +  Residual hospital-related CF
• Because nearly all patients with non-fatal definite myocardial infarctions are hospitalized, we have approximately:
  28-day CF for hospitalized events =
  = Residual hospital-related CF / (1 - Pre-hospital CF)

Case fatality in age group 35-64 years was standardized for age using weights 1, 3 and 7 for the 10-year age groups 35-44 years, 45-54 years and 55-64 years respectively. The weights 1, 3 and 7 are approximately proportional to the numbers of coronary events in the 10-year age groups in the MONICA populations.

95% confidence intervals were calculated in the conventional manner using the normal approximation of binomial distribution.

References

1. Chambless L, Keil U, Dobson A, Mähönen M, Kuulasmaa K, Rajakangas A-M, Löwel H, Tunstall-Pedoe H for the WHO MONICA Project. Population versus clinical view of case fatality from acute coronary heart disease: results from the WHO MONICA Project 1985-1990. Circulation 1997;96:3849-3859
2. Tunstall-Pedoe H, Vanuzzo D, Hobbs M, Mähönen M, Cepaitis Z, Kuulasmaa K, Keil U, for the WHO MONICA Project. Estimation of contribution of changes in coronary care to improving survival, event rates and coronary heart disease mortality across the WHO MONICA Project populations. Lancet 2000;355:688-700.
3. WHO MONICA Project. MONICA Manual. Part IV: Event registration. Section 1: Coronary event registration data component. (March 1999). Available from: URL: http://www.thl.fi/publications/monica/manual/part4/iv-1.htm, URN:NBN:fi-fe19981154.

Acknowledgements

The MONICA Centres are funded predominantly by regional and national governments, research councils, and research charities. Coordination is the responsibility of the World Health Organization (WHO), assisted by local fund raising for congresses and workshops. WHO also supports  the MONICA Data Centre (MDC) in Helsinki. Not covered by this general   description is the ongoing generous support of the MDC by the National  Public Health Institute of Finland, and a contribution to WHO from the National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA for support of the MDC and the Quality Control Centre for Event Registration in Dundee. The completion of the MONICA Project is generously  assisted through a Concerted Action Grant from the European Community. Likewise appreciated are grants from ASTRA Hässle AB, Sweden, Hoechst AG, Germany, Hoffmann-La Roche AG, Switzerland, the Institut de Recherches Internationales Servier (IRIS), France, and Merck & Co. Inc., New Jersey, USA, to support data analysis and  preparation of publications.