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Although national mortality statistics for diabetes mellitus are often quoted in the literature, problems with their validation need to be overcome. They are based upon the assignment of diabetes as the so-called "underlying cause of death", which has several limitations when applied to studies of diabetes mortality. The EURODIAB Sub-Area C study group has carried out simulation studies which indicate that European variations in physicians' certifying practices and national coding procedures could explain about 35% of the variation in published European mortality rates for diabetes. Some of these problems can be overcome by the use of a "multiple-cause" encoding procedure which is recommended for monitoring of the targets of the St Vincent Declaration Action Programme for Europe. Studies of specific causes of death in cohorts of subjects with insulin-dependent diabetes mellitus indicate that many of these premature deaths are potentially avoidable. The major cause of death in patients with non-insulin-dependent diabetes continues to be cardiovascular disease. Studies in England and Wales indicate the diabetic patients are not experiencing the same fall in cardiovascular mortality as that experienced by the general population.

Trends in diabetes-related mortality in England and Wales between 1975-6 and 1985-6, and regional and ethnic differences in diabetes-related mortality in 1985-6, have been examined. Data from death certificates mentioning diabetes in 1975-6 were compared with those for 1985-6 for different age groups. Data for 1985-6 were also analysed for different regions of England and Wales, and for country of birth. Between 1975-6 and 1985-6, the age-standardized rate of mentioning diabetes rose by 2.7% (95% confidence interval 1.4%, 4.1%) in men of all ages, and fell by 11.7% (10.6, 12.8) in women of all ages. By contrast, the rate of mentioning diabetes in those below 45 years fell by 30.7% (23.0, 37.7) in men and by 26.7% (16.5, 35.6) in women. Deaths in which the underlying cause was ischaemic heart disease (IHD), and where diabetes was also mentioned on the death certificate, rose by 14.4% (11.5, 16.8) in men and did not change significantly in women of all ages, but fell by 18.4% (-35.1, +2.6) in men, and 23.5% (-49.1, +15.2) in women below age 45. This was less favourable than the trend in the general population, where IHD mortality fell by 9.7% in men and 8.3% in women of all ages, and by 31.1% (28.6, 33.5) in men and 40.5% (35.0, 45.5) in women under 45 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Data from the clinical records of patients known to have diabetes and admitted to hospital in North West London, Cambridge or Newcastle were compared with data on the same admissions taken from the system responsible for recording information on all acute hospital admissions (Hospital Activity Analysis). In 89 out of 751 admissions (12%), either the sex, date of birth or marital status of the patient was incorrectly recorded. The diagnosis of diabetes was omitted in 32 (10%) of 315 admissions in which diabetes or a complication of diabetes was regarded as the principal cause of admission and in 12 (23%) out of 53 in which the principal cause was closely related to diabetes. These included cases in which the diagnosis had not been stated (by the clinician) on the discharge summary (the source document for Hospital Activity Analysis) as well as instances in which the coding clerk had failed to record the diagnosis. The validity of information collected on hospital admissions is dependent on the presentation of data by the clinician to the coding clerk. There may be a lack of awareness of the importance of the clinical discharge summary as a source document for such systems.

Clinical and autopsy evidence support the increased risk of atherosclerotic disease in diabetes mellitus (DM). However, mechanisms other than arterial occlusion may also contribute to clinical syndromes often assumed to be atherosclerotic in origin. There is considerable geographical variability in the frequency of arterial disease in the diabetic. Glucose intolerance short of unequivocal DM is found in some (though not all) populations to carry increased atherosclerotic risk. Morbidity and mortality data suggest that women are particularly vulnerable (as with DM). The Whitehall prospective study of cardiovascular mortality shows that risk does not rise smoothly with increasing degrees of glucose intolerance but that it doubles sharply at the 95th percentile of the 2-h post-glucose blood sugar distribution.