Clinical and Epidemiological Studies on Canine Diabetes Mellitus

Veterinary science, Animal diseases

Graham, Peter Andrew

University:University of Glasgow

关键词: Veterinary science, Animal diseases;   

Others  :  http://theses.gla.ac.uk/74678/1/10992300.pdf

来源: University of Glasgow

【 摘 要 】

The aim of the work presented in this thesis was to investigate aspects of canine diabetes mellitus in order to improve understanding of the condition and the welfare of dogs affected by it. The epidemiology, clinical chemistry and survival data of diabetic dogs treated by the author during the period October 1989 to August 1994 were studied. In addition, studies on specific insulin and dietary formulations were undertaken. Epidemiological studies employing statistical comparisons with a time-matched hospital derived control population revealed a complicated relationship between age and gender associated with diabetes mellitus, in that females in the older age groups were at greatest risk but in the younger age groups they were not. Predisposed breeds were terriers (particularly Tibetan, Cairn and Jack Russell), collie crossbreeds and Rottweilers. There were differences between the epidemiological characteristics of diabetic dogs of high risk breeds and those of normal or low risk breeds suggesting a possible difference in pathophysiology. Investigation of diabetic dogs with associated syndromes revealed differences in age distribution between those with hypothyroidism, those with hyperadrenocorticism and 'normal' diabetic dogs and that basal plasma insulin analysis prior to ovariohysterectomy may be a useful prognostic indicator in metoestrus-associated diabetes mellitus. 'New' tests, fructosamine and glycated haemoglobin, validated for use with canine samples, were determined to be useful in the monitoring of canine diabetes mellitus by relative operating characteristic curve analysis. Alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase were not useful tests for this purpose. A highly purified porcine insulin zinc suspension had two reasonably predictable times of peak activity following subcutaneous injection at around 4 and 11 hours and an overall duration of activity of 14 to 24 hours. The efficacy of the same product, studied during a stabilisation and follow-up period in 19 diabetic dogs, was good in both the short and long term. Stabilisation was achieved in 10 - 14 days resulting in a final dose of between 0.8 and 2.0 IU/kg. The rates of bacterial infections and blindness associated with the long term use of this product on a single daily basis were 1 per 1.11 and 1 per 2.23 diabetic-dog-years, respectively. The feeding of a commercially produced 'high fibre' diet reduced mean 24 hour plasma glucose concentration and the fluctuation in afternoon post-prandial glycaemia. Feeding this diet also improved demeanour and activity scores and plasma concentrations of afternoon glucose, fructosamine and alkaline phosphatase. In addition, reductions were observed in plasma concentrations of total cholesterol, LDL cholesterol, free glycerol and non-esterified fatty acids. There was an association between feeding this diet and weight loss, reduced body condition scores and increased faecal volume score. In the very long term (> 4 months) there was a subjectively high prevalence of unexpected weight loss, recurrent diarrhoea and small intestinal bacterial overgrowth. Median survival time for diabetic dogs treated with single daily injections of insulin was 2.71 years. Median remaining lifetime increased to 3.11 years for those dogs which survived the first 5 months of therapy. There was no effect on survival of gender or of the type of intermediate duration insulin preparation, but diabetic dogs with hyperadrenocorticism had a much poorer prognosis. Survival rates for diabetic dogs were close to or greater than those of an age and gender-matched general canine population, using a necropsy based modified cohort general life table.