Melbourne School of Population and Global Health - Research Publications

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Author: Guymer, Robyn × End date: 2009 × Start date: 2008 × Type: Journal Article ×

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    Novel measures of cardiovascular health and its association with prevalence and progression of age-related macular degeneration: the CHARM study
    McCarty, CA ; Dowrick, A ; Cameron, J ; McGrath, B ; Robman, LD ; Dimitrov, P ; Tikellis, G ; Nicolas, C ; McNeil, J ; Guymer, R (BMC, 2008)
    BACKGROUND: To determine if novel measures of cardiovascular health are associated with prevalence or progression of age-related macular degeneration (AMD). METHODS: Measures of the cardiovascular system: included intima media thickness (IMT), pulse wave velocity (PWV), systemic arterial compliance (SAC), carotid augmentation index (AI). For the prevalence study, hospital-based AMD cases and population-based age- and gender-matched controls with no signs of AMD in either eye were enrolled. For the progression component, participants with early AMD were recruited from two previous studies; cases were defined as progression in one or both eyes and controls were defined as no progression in either eye. RESULTS: 160 cases and 160 controls were included in the prevalence component. The upper two quartiles of SAC, implying good cardiovascular health, were significantly associated with increased risk of AMD (OR = 2.54, 95% CL = 1.29, 4.99). High PWV was associated with increased prevalent AMD. Progression was observed in 82 (32.3%) of the 254 subjects recruited for the progression component. Higher AI (worse cardiovascular function) was protective for AMD progression (OR = 0.30, 95%CL = 0.13, 0.69). Higher aortic PWV was associated with increased risk of AMD progression; the highest risk was seen with the second lowest velocity (OR = 6.22, 95% CL = 2.35, 16.46). CONCLUSION: The results were unexpected in that better cardiovascular health was associated with increased risk of prevalent AMD and progression. Inconsistent findings between the prevalence and progression components could be due to truly different disease etiologies or to spurious findings, as can occur with inherent biases in case control studies of prevalence. Further investigation of these non-invasive methods of characterizing the cardiovascular system should be undertaken as they may help to further elucidate the role of the cardiovascular system in the etiology of prevalent AMD and progression.
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    Cost-effectiveness of smoking cessation to prevent age-related macular degeneration.
    Hurley, SF ; Matthews, JP ; Guymer, RH (Springer Science and Business Media LLC, 2008-09-11)
    BACKGROUND: Tobacco smoking is a risk factor for age-related macular degeneration, but studies of ex-smokers suggest quitting can reduce the risk. METHODS: We fitted a function predicting the decline in risk of macular degeneration after quitting to data from 7 studies involving 1,488 patients. We assessed the cost-effectiveness of smoking cessation in terms of its impact on macular degeneration-related outcomes for 1,000 randomly selected U.S. smokers. We used a computer simulation model to predict the incidence of macular degeneration and blindness, the number of quality-adjusted life-years (QALYs), and direct costs (in 2004 U.S. dollars) until age 85 years. Cost-effectiveness ratios were based on the cost of the Massachusetts Tobacco Control Program. Costs and QALYs were discounted at 3% per year. RESULTS: If 1,000 smokers quit, our model predicted 48 fewer cases of macular degeneration, 12 fewer cases of blindness, and a gain of 1,600 QALYs. Macular degeneration-related costs would decrease by $2.5 million if the costs of caregivers for people with vision loss were included, or by $1.1 million if caregiver costs were excluded. At a cost of $1,400 per quitter, smoking cessation was cost-saving when caregiver costs were included, and cost about $200 per QALY gained when caregiver costs were excluded. Sensitivity analyses had a negligible impact. The cost per quitter would have to exceed $77,000 for the cost per QALY for smoking cessation to reach $50,000, a threshold above which interventions are sometimes viewed as not cost-effective. CONCLUSION: Smoking cessation is unequivocally cost-effective in terms of its impact on age-related macular degeneration outcomes alone.