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Thesis (M. P. H.)--University of Hong Kong, 2007.

Titanium bone plates and screws are commonly used in oral and maxillofacial surgery for internal fixation. Although titanium plate is good for fixation of bone fractures, there are still somemany disadvantages of the material. Biodegradable materials are considered to be good alternatives for treatment of the facial bone fractures. Poor wound healing in diabetic animals and human was well known. The aims of the studies were to compare the strength and tissue reaction of the poly lactic-co-glycolic acid ¡]PLGA¡^ with titanium plates used as fixation material in fractured-femora of diabetic and normal animals. The results of the studies show that the wounds of the control group healed quite well and there was no discharge around the wound. However, bullas formation was found in all the diabetic wounds fixed with PLGA. There was fistula with pus and gas discharge around the bullas. In the control group, the diameter of the PLGA-fixed femur was larger than the titanium-fixed femura. There was a large amount of callus formation around the PLGA-fixed fracture femur. At the 20th day, the defects of both groups of the PLGA treated were not healed. A large amount of new bone formation in normal titanium-treated rats was found, while in diabetic rats, mainly a fibrous tissue reaction. At the 40th day, the diabetic PLGA-fixed femora were poorly healed with a large amount of fibrous tissue. Similarly, after 40 days in the titanium-fixed femora of diabetic rats, extensive fibrosis of the defect was also present. In normal PLGA-fixed fractured femora, there was a large amount of cartilage present around the defect. Most of the normal PLGA-fixed fractured femora were distorted in shape. At the 40th day, lamellar bone formation was found around the screw in normal titanium-fixed femora and the defect was healed. In conclusion, the PLGA plate is not suitable for fixation in the fractured-femora of the rats in either normal or diabetic groups when compared with those from titanium plate treat groups. It is because of less strength of the PLGA plate and the material easily cause tissue reaction in the rat which result in the formation of large amount of fibrous tissue around the PLGA screw instead of bone.

Background: Screening for diabetic retinopathy (DR) has been proven effective and cost-effective in preventing blindness. Hong Kong (HK) has a mixed health care economy and, before this study, there was no systematic screening for DR. The optimal screening interval for DR screening is controversial with some countries extending it to 2 or more years. Risk algorithms tailor screening intervals to an individual but the safety of a 2-year interval and the validity of the Iceland Risk Algorithm (IRA) are uncertain in HK. This study assesses the impact of charging a co-payment for DR screening in the public sector, evaluates its cost-effectiveness and examines the use of an algorithm to determine optimal screening intervals for subjects in HK. Methods: A randomized controlled trial (RCT) was conducted with subjects with diabetes from two general outpatient public clinics randomized to free screening or pay screening with a co-payment of HK$60. Cost-effectiveness analysis used a Markov cohort model to compare these with opportunistic screening. Incremental cost-effectiveness ratios (ICERs) were calculated and one way and probabilistic sensitivity performed. Subjects were followed up for two years to examine the safety of a 2-year screening interval and to test the validity of the IRA in predicting sight threatening diabetic retinopathy (STDR). A new prediction model using cohort data was developed using logistic regression and tested in a similar fashion. Results: After randomization, 1316 in the free and 1277 in the pay group agreed to participate. Uptake of screening was 88.5% (1165/1316) and 82.4% (1052/1277) in free and pay groups respectively (Pearson chi=19.74, P<0.001). Being in the pay group was associated with lower uptake of screening (OR=0.59, 0.47 to 0.74) and lower detection rates of DR (OR=0.73, 0.60 to 0.90) after adjustment. From the societal perspective, pay systematic DR screening rather than opportunistic screening gives an ICER of HK$94,630/QALY gained. Free rather than pay systematic screening, had an ICER of HK$199,741/QALY gained. Probabilistic sensitivity analysis showed when willingness to pay for a QALY was HK$186,186 or more, free systematic screening had the highest probability of being cost-effective. The 2-year cumulative incidence of STDR was low for those with no DR (2.9%) and those who developed STDR did not experience severe visual loss during follow up. The IRA had good discrimination for identifying STDR, but significantly lacked calibration. The new prediction model improved discrimination and calibration compared with the IRA. Conclusion: A number of people in the pay group did not uptake screening and appear to be higher risk cases. The inverse care law appears to operate even with this relatively small co-payment. From the societal perspective, free systematic screening was more cost-effective than pay within the WHO threshold of 1 x annual per capita GDP (HK$338,520) for a QALY. Free systematic screening can be considered the most cost-effective screening strategy from the societal perspective. We could tailor screening intervals according to individual risks using a new prediction model which appears safe and efficient but which requires further testing with follow-up data. / published_or_final_version / Public Health / Doctoral / Doctor of Philosophy

Thesis (M. P. H.)--University of Hong Kong, 2007. / Also available in print.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 4 uppsatser.

Introduction: Diabetes in Africa has been described as a pandemic, with the prevalence in South Africa estimated at 4.5% of the population. Despite clear national guidelines from the Society of Endocrinology, Metabolism and Diabetes of South Africa, an unpublished quality improvement cycle in 2007 has shown poor patient knowledge with associated uncontrolled glycaemic and hypertensive control in diabetic patients in a district health system. The purpose of the study was to identify possible reasons for this and to find solutions for improving diabetic care within the Wesbank/ Ilingu Lethu suburb of Malmesbury, Western Cape. Methods: A cooperative inquiry group was established, consisting of primary health care providers at a district hospital and a primary health care clinic. The inquiry completed several cycles of action-reflection over a period of eight months, and included training in diabetic related topics and critical reflection techniques. At the end of the inquiry consensus was reached on key findings by group and learning within the group. Findings: Consensus was expressed in two key findings. The group identified and prioritized continuity of care and diabetic education key areas where diabetic care could be improved in the research population. The first was addressed by initiating diabetic registries, establishment of a regular diabetic clinic, implementation of a diabetic schedule within the medical records and the forming of a diabetic team that could support continuity of relationships, clinical management and organisation of care between both facilities. The diabetic team involved non-governmental organizations, private health providers and the community to increase awareness and develop capacity to improve diabetic care. The other finding confirmed diabetic education as a critical area in diabetic self management. The diabetic team initiated a diabetic community forum for educational and informative group activities. There was also continued professional development with education sessions within the cooperative inquiry group themselves. Conclusions: Improving diabetic care through continuity of care and education is well supported in known evidence based literature. The challenge is to translate/ transfer the available knowledge and render it operational and clinical in any health setting. The co-operative inquiry process was a valuable tool to identify, prioritized and addresses unique challenges for improving diabetic care in our specific context.

The accurate assessment of human diabetic somatic polyneuropathy (DSPN) is important to define at risk patients, predict deterioration, and assess the efficacy of pathogenetic treatments. Corneal confocal microscopy (CCM) has been proposed as a surrogate endpoint for DSPN. Approximately 50% of patients with DSPN experience neuropathic pain or symptoms and the underlying reasons are not clearly elucidated. Vitamin D deficiency has been associated with diabetic complications including DSPN and diabetic retinopathy (DR). However there is a paucity of data regarding the interaction of vitamin D status with diabetic complications. This thesis shows that CCM can readily detect small fibre neuropathy prior to large fibre involvement and assess rapidly progressive nerve fibre loss prior to conventional thermal threshold testing. CCM has a superior diagnostic capabilities compared to intra-epidermal nerve fibres and correlates better with nerve conduction studies. Patients with LADA have a greater prevalence of small fibre neuropathy compared to matched patients with type 2 diabetes. Vitamin D deficiency is highly prevalent in patients with diabetes and despite relatively aggressive replacement regimens are inadequate in raising vitamin D levels in a significant proportion of patients. Vitamin D deficiency is not associated with DR but there is a strong association between painful DSPN and vitamin D insufficiency and more so with overt deficiency.

PURPOSE: Diabetic macular edema (DME) is the most common cause of vision loss in patients with diabetic retinopathy. This study aims to approach diabetic macular edema and diabetic retinopathy as ischemic conditions and explores a potential treatment through hyperoxia. The study measured changes in retinal thickness, visual acuity, and contrast sensitivity in subjects receiving normobaric oxygen. METHODS: Fifty-one patients with diabetic macular edema at Beth Israel Deaconess Medical Center Eye Clinic (Boston, MA) received oxygen via a face mask at 5 liters per minute for 3 hours. Retinal thickness at the central subfield and maximal retinal thickness were measured using optical coherence tomography. Contrast sensitivity, best corrected visual acuity, and intraocular pressure were measured before and after oxygen as well. RESULTS: Macular thickness from diabetic macular edema decreased by an average of 2.09% (p < .05) at the point of maximal thickness, and by 0.88% (p < .05) at the central subfield. Vision also improved by an average of 0.043 LogMAR units (p < .05). Changes in macular thickness and visual acuity were non-significant in healthy control eyes that received oxygen. The results of hyperoxia on contrast sensitivity were indeterminate. CONCLUSIONS: We found that normobaric hyperoxia for 3 hours reduces macular thickness from diabetic macular edema and improves visual acuity. This study offers additional evidence that diabetic macular edema is an ischemic disorder and suggests that oxygen therapy may serve as an alternate or complimentary treatment of DME. / 2020-06-17T00:00:00Z

Jiang, Guozhi. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 147-157). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.