Comparison of different procedures to identify probable cases of myocardial infarction and stroke in two Swedish prospective cohort studies using local and national routine registers
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In prospective cohort studies, person-time time is calculated from baseline until the first definite event occurs or until censoring. A way to correctly identify and date definite events when only routine registers are available is to retrieve all hospital discharge notes and death certificates with a diagnosis of probable event and perform a consecutive revision. It is important to detect all possible hospital stays as they may contain useful information for the revision study. Furthermore, loss to follow-up can be avoided by extending the retrieval outside the specific geographical area where the cohort was defined. The aims of this study were (i) to describe a comprehensive retrieval of probable myocardial infarctions (diagnosis with International Classification of Diseases 8th and 9th revisions codes 410–414) or stroke (codes 430–438), (ii) to quantify the relative efficiency of different local and national routine registers or their combination compared with the use of all available registers together, and (iii) to audit local and national registers by comparing their outcome at the county level. The study was performed in two prospective cohorts studies i.e., `Men-born-1914' (n = 500) from Skåne (period 1982–1993), and Skara-1 (n = 683) from Skaraborg (period 1988–1994.). All available routine registers were linked to the cohorts. The use of all available routine registers improved retrieval of both individual and hospital stays with a discharge diagnosis of probable event and gave an enhanced basis for a future validation study. Local registers were not completely covered by the national register, but the accessible combination of national in-patient and mortality registers was an efficient alternative.
- Lindblad U, Rastam L, Ranstam J, et al. Validity of register data on acute myocardial infarction and acute stroke: The Skaraborg Hypertension Project. Scand J Soc Med 1993; 21: 3–9.
- Sudlow CL, Warlow CP. Comparing stroke incidence worldwide: what makes studies comparable? Stroke 1996; 27: 550–558.
- Kannel WB, Abbott RD. Incidence and prognosis of unrecognized myocardial infarction. An uppdate on the Framingham Study. N Eng J Med 1984; 311: 1144–1147.
- Stegmayr B, Asplund K. Measuring stroke in the population: Quality of routine statistic in comparison with a population-based stroke registry. Neuroepidemiology 1992; 11: 204–213.
- Mahonen M, Salomaa V, Brommels M, et al. The validity of hospital discharge register data on coronary heart disease in Finland. Eur J Epidemiol 1997; 13: 403–415.
- Rothman KJ, Greeland S. Precision and validity in epidemiologic studies. In: Modern Epidemiology. 2nd edn. Philadelphia: Lippincott-Raven, 1998: 115–134.
- Isacsson S-O. Venous occlusion plethysmography in 55-year-old men. A population study in Malmö, Sweden. Dissertation. Acta Med Scand Suppl 1972; 537: 1–62.
- Janzon L, Hanson BS, Isacsson S-O, et al. Factors influencing participation in health surveys: results from the prospective study ‘Men born in 1914’ in Malmö, Sweden. J Epidemiol Community Health 1986; 40: 174–177.
- Rastam L, Eckerlund I, Ryden L. Hypertension case-identification in primary health care. Experience from the Skaraborg Hypertension Project. Scand J Prim-Health Care 1987; 5: 9–12.
- Rastam L. A program for the management of hypertension: An evaluation of structured hypertension care in the county of Skaraborg, Sweden (Vårdprogram för högt blodtryck: ett försök med strukturerad hyper-tonivård i Skaraborgs län). Dissertation. Gothenburg University, 1983. Spri-rapport; 138. Stockholm. (In Swedish).
- Lindblad U. The prognosis of hypertension: The Skaraborg hypertension project. Dissertation. Department of Community medicine, Malmö. Lund University, 1993.
- Jerntorp P, Berglund G. Stroke registration in Malmö. Stroke 1992; 23: 357–361.
- Ögren M, Hedblad B, Isacsson S-O, et al. Ten years cerebrovascular morbidity and mortality in 68 year-old men with asymptomatic carotis stenosis. Br Med J 1995; 310: 1294–1298.
- Ahlbom A. Acute myocardial infarction in Stockholm-a medical information system as an epidemiological tool. Int J Epidemiol 1978; 7: 271–276.
- Hammar N, Nerbrand C, Ahlmark A, et al. Identification of cases of myocardial infarction: Hospital discharge data and mortality data compared to myocardial infarction community registers. Int J Epidemiol 1991; 20: 114–120.
- Alfredsson L, Hammar N, Hodell A, et al. Quality evaluation of diagnosis acute myocardial infarction in three Swedish counties 1995 (Värdering av diagnos-kvaliteten för akut hjärtinfarkt i tre svenska län 1995). Projektrapport från Socialstyrelsen. Artikelnr 1997: 84–8 (In Swedish).
- Jansson B, Johansson LA, Rosen M, et al. National adaptations of the ICD rules for classification-a problem in the evaluation of cause-of-death trends. J Clin Epidemiol 1997; 50: 367–375.
- SCB-90 Classification of causes of death in Swedish Statistics. Reports on statistical co-ordination 1990; 3: 286. Statistics Sweden.
- Comparison of different procedures to identify probable cases of myocardial infarction and stroke in two Swedish prospective cohort studies using local and national routine registers
European Journal of Epidemiology
Volume 16, Issue 3 , pp 235-243
- Cover Date
- Print ISSN
- Online ISSN
- Kluwer Academic Publishers
- Additional Links
- Case identification
- Cohort studies
- Myocardial infarction
- Industry Sectors
- Author Affiliations
- 1. Department of Community Medicine, Lund University, Malmö University Hospital, Malmö, Sweden
- 2. The NEPI Foundation Malmö and Stockholm, Sweden
- 3. Skaraborg Institute, Skövde, Sweden
- 4. Department of Internal Medicine, Lund University, Malmö University Hospital, Malmö, Sweden