Patients of Asian ethnic origin with diabetes mellitus living in the United Kingdom (UK) have been shown to have a higher prevalence of coronary heart disease and renal disease. Little is known about the incidence of lower extremity amputation in this racial group. The incidence of lower extremity amputation was estimated for patients of Asian ethnic origin and White Caucasians with diabetes mellitus in the county of Leicestershire from 1980 to 1985. The age and sex-adjusted incidence rate of lower extremity amputation for the estimated population of patients with diabetes mellitus in patients of Asian ethnic origin was 3.4 (95% CI, 1.1-10.7) cases per 10,000 patients year-1, compared to 14.2 (12.6-15.9) in White Caucasians. Similarly, a lower incidence rate of lower extremity amputation was recorded in patients of Asian ethnic origin without diabetes mellitus (0.4 (0.2-0.6) vs 1.5 (1.4 to 1.6) cases per 10,000 persons year-1). These findings contrast markedly with the high rates of coronary heart disease and renal disease previously reported in patients of Asian ethnic origin residing in the UK.
Fifteen patients receiving standard thyroxine replacement therapy (100-200 Rtg daily) for primary hypothyroidism and who had persistently raised free thyroxine concentrations in their serum were investigated to see whether the dose being given was too high. In addition to the usual thyroid hormone assays systolic time intervals (which indicate left ventricular contractility) were calculated as accurate reflectors of tissue thyroid activity.All patients showed the expected increased free and total thyroxine concentrations; but mean total and free concentrations of triiodothyronine were normal, while reverse triiodothyronine values were raised. Mean systolic time intervals were significantly reduced as compared with normal and fell within the thyrotoxic range.Seven patients subsequently had their doses of thyroxine reduced by 50 ttg daily and were reinvestigated one month later. All showed significant falls in circulating thyroxine and triiodothyronine concentrations and an increase in mean systolic time intervals to the normal range.In patients receiving thyroxine replacement therapy for primary hypothyroidism a raised serum thyroxine concentration may indicate tissue thyrotoxicosis and should prompt a reduction of the thyroxine dose.
Fifteen selected hypothyroid patients without symptoms or signs of cardiovascular disease and an equal number of matched control subjects underwent simultaneous recording of electrocardiogram and phono-, apex-, and echocardiography to assess dynamic systolic and diastolic left ventricular function. Both the systolic preejection period and the isovolumic relaxation period were significantly increased in the hypothyroid group. However, whereas the rate of myocardial contraction, assessed from the echocardiograph of the left ventricular posterior wall, was identical in patients and control subjects, the diastolic thinning rate of the muscle was markedly slowed in the hypothyroid individuals. The abnormalities demonstrated were in the main completely reversed after 3 months of T4 therapy. These results demonstrate a relatively selective and readily reversible disturbance of the rate of myocardial relaxation in hypothyroidism, suggesting an intrinsic abnormality of cardiac muscle. This allows an intriguing parallel to be drawn with the delayed relaxation phase of voluntary muscle contraction, long recognized as a direct measure of tissue thyroid function in hypothyroidism. The abnormality of diastolic function we have described is of similar character to that found in patients with other cardiomyopathies and which has been shown to be a major cause of disturbance of global cardiac action.
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