Medical Databases

Turku 22 January 1999 Finland has an exceptionally complete demographic data, which enables large epidemiological studies. A database called the Mini-Finland, with the medical information of 8,000 citizens over 30 years of age, portrays the average Finn with his or her diseases.

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Finland has an exceptionally complete demographic data, which enables large epidemiological studies. A database called the Mini-Finland, with the medical information of 8,000 citizens over 30 years of age, portrays the average Finn with his or her diseases.

Note from the VMW editorial team:
"Medical Databases" already appeared in December 1998 in CSC News, the magazine on High Performance Computing and Networking in Finland, Volume 10, No 4. VMW wishes to kindly thank the CSC News Editorial Staff and the author, Dr. Martti Kormano, Professor of Diagnostic Radiology, University of Turku, Finland, for granting permission to publish the article.

Public health care has a long history and very good coverage in Finland. One of the spin-offs is a high number of well-maintained health care related databases. It has been claimed that there are about 500,000 databases that contain information on personal data. Many of them include health care or related information. The individual social security number in Finland is bound to the data of birth and is used in nearly all instances, including all health care, which makes it - at least theoretically - possible to relate medical data with many other datasets. In fact, hospitals and health centers are connected to the Population Register Center of Finland, from which demographic data is drawn. This is possible in a small nation and results in both positive and negative possibilities concerning medical research.

The availability of unusually complete demographic data enables exceptional epidemiological studies also internationally. Such studies include for example cardiovascular diseases and cancer. Based on the database of the Central Statistical Office, it is possible to create geographic maps that relate to the frequency of various diseases as the cause of death. The rare homogeneity of the Finnish population enables conclusions that could be difficult in more heterogeneous populations, because the ethnic variable is practically excluded. However, the Finnish practice may allow illegal use of data, unless carefully controlled.

National statewide databases

The Central Statistical Office of Finland maintains a database on death certificates that has existed for over 50 years. There are other databases with good national coverage, such as the Central Population Register, which contains information on family relations (kinship).

The National Board of Health and its subsidiaries maintain databases on children born (since 1987), abortions and sterilization's (since 1977), hospitalizations (since 1994), blindness (since 1983), and malformations (since 1963). Other databases maintained by the National Board of Health include registers on side effects, drugs, and medical implants.

The National Cancer Society has maintained the Finnish Cancer Registry since 1952. It already contains 700,000 cancer cases. Other databases maintained by The National Cancer Society include registers on uterine cervical cancer screening and mammography screening. The National Health Institute maintains a database on infective diseases.

More information of Finnish medical databases can be acquired from several recent publications (1-3). Basic sets of statistical information in medicine as CD-ROMs are published by the Institute of Occupational Health (TURVA-CD) and by the Ministry of Health and Welfare (SOTKA).

Also the Finnish Social Insurance Institute has collected large databases. A database called Mini-Finland contains medical information on 8,000 Finnish citizens over 30 years old. It is considered to be a set of average Finnish individuals, including their diseases. It has been used for research in a variety of ways.

There are also databases created and maintained by societies, which have a good enough coverage to serve nationwide epidemiological research. An example is the nationwide database on renal diseases, maintained by the Finnish Society of Renal Diseases. A review of such databases was published recently (4). They include information on 31 databases on national or local level and lists of some Swedish and Danish databases.

There are even nationwide databases maintained by researchers. Probably the best known database is the Finnish twin registry, maintained by professors Jaakko Kaprio and Markku Koskenvuo. It covers information on twin births in Finland from 1956 to 1986, including 22000 families. It has been a resource to a large number of epidemiological studies recognized worldwide.

The above mentioned databases are available for researchers. Some more general databases do not contain confidential information. But databases that contain information on individuals, require commitment to confidentiality, before they can be made available for research purposes.

Databases in current health care

All hospitals and health centers have their own databases, which relate to the Population Registry of Finland. Medical databases were hand-written documents in the fifties, typewritten reports in the sixties, and since the eighties have slowly been transferred into electronic databases. The leaders of this progress have been laboratory medicine and pathology, followed by radiology. The electronic database of general hospital records still needs several years to be reality. Many projects have been started, but their slow progress has made them outdated before release.

The heaviest hospital database is the radiology image archive. A typical digital radiology image is as big as 7-8 MB, uncompressed. Such databases require a very efficient data network and a working connection between the hospital information system (HIS), radiology information system (RIS), and the picture archiving and communication system (PACS). The only Finnish PACS to contain hundreds of thousands of images is at the Turku University Hospital, where a digital image archive has been in use since October 1995. For scientific purposes, such huge databases are not an easy source. Confidentiality rules, and firewalls prevent their use as such unless the images and the patient's identification data are completely separated. The latter requires a lot of work.

International medical databases

There are hundreds of medical databases available for anyone in the Internet. Unfortunately, there is no quality control in general. The reviewer has to judge whether the information given is valid or not. Probably the most significant and also the largest database is the Visible Human Project maintained by the National Library of Medicine, USA. It contains detailed, cross-sectional, and anatomical CI and MRI images of a single male and female cadaver. They are supposed to be useful in teaching anatomy, pathology, and radiology to medical students. However, these databases are so large (gigabytes), that their retrieval over the Internet is a problem and require mirroring for local use.

References

  1. Koskenvuo K, Vertio H: Sairauksien ehkäisy. Kustannus Oy Duodecim, 1998. A report on preventing illnesses.
  2. Tilastot, rekisterit ja tietojärjestelmät-yksikön aineistot: Stakes Telastotiedote 10/96. Statistics.
  3. Mitä on jo kysytty?, Sosiaali- ja terveydenhuollosta kerättyä tietoa 1996-1997. Stakes, Tilastoraportti 14/98. Statistics.
  4. Mäkelä M, Lappalainen M, Orre S: Terveydenhuollon erillisrekisterit. FinOHTAn raportti 3/1997. A report on registers.


Martti Kormano, MD

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