本帖最後由 goodcat1111 於 2009-4-30 14:57 編輯
作者：Fran Lowry
出處：WebMD醫學新聞
April 13, 2009 — 根據一篇發表於4月版眼科學檔案期刊上模擬未來AMD發生率模式的研究結果，美國老年性黃斑部病變(AMD)的病例將於2010至2050年隨著人口老化而明顯增加；不過，研究者表示，使用抗氧化維他命和其他新治療可以減少這些視力不佳和眼盲達35%。
北卡羅來納三角研究園區、國際三角研究中心的David B. Rein博士以及視力健康成本效益研究小組的研究夥伴寫道，新發現的預防性與治療性AMD治療，提供了比過去的治療方式更明顯的改善，可以某種程度的減少未來的AMD發病率。若新的AMD治療廣為適用，可延遲末期AMD發生、縮減脈絡膜新生血管(CNV)的視力影響，而可以改變此病未來的爆發。
研究目標是預測在2050年時，有多種治療方法時的AMD流行病學。
研究者分別根據5種治療場景，模擬早發AMD、CNV、地圖狀萎縮(GA)以及可歸因於AMD的視力缺損和眼盲案例，5種治療場景包括(1)沒有治療；(2)病灶雷射以及光動力治療(PDT)治療CNV；(3) 用維他命預防早期AMD發生，使用病灶雷射/PDT治療CNV；(4)沒有使用維他命預防，之後使用雷射治療視網膜中央凹旁及視網膜中央凹外CNV，以及使用抗血管內皮生長因子(anti-VEGF)治療；(5)用維他命預防早期AMD發生，之後用和(4)一樣的CNV治療。
在使用維他命預防的場景中，研究者假設這些人是使用Age-Related Eye Disease Study (AREDS)所建議的抗氧化維他命加鋅這個處方。
模擬模式是根據AREDS簡化量表。在這個模式中，各種場景的早期AMD案例從2010年的910萬增加到2050年的1780萬。
使用維他命改變了預測的末期AMD案例數，在場景(3)和(5)中，此案例數減少達25%。
在缺乏抗氧化維他命和抗VEGF治療下，視力缺損和眼盲的案例從2010年的620,000例增加到2050年的160萬例。 不過，此數據在場景2減少2.4%、場景3減少22.0%、場景4減少16.9% 、場景5減少34.5%。
作者寫道，此研究有許多限制。採模擬模式，試圖使用當代資料來預測遙遠未來的結果，但是未考量未來治療科技的改變會影響AMD的預測和結果，且此研究假設AMD的年齡特定發生率與預後在2050年時都一樣。作者寫道，雖然我們試圖緩和使用敏感度分析的不確定資料影響，但和所有的預測一樣，這些應被視為含有諸多不確定因素的估計。
Rein博士等人也警告，臨床試驗中，有關抗VEGF治療24個月後的效果所知有限。此外，抗VEGF治療對於治療各種CNV的能力，除了視網膜中央凹下CNV之外也都還不清楚。
此模式也假設完全遵守現有使用抗氧化維他命和抗VEGF治療的臨床建議。作者指出，病患實際上使用這些治療的比率可能較低。
他們結論表示，公共預防努力應聚焦在讓早期AMD病患擴大使用抗氧化維他命，也應朝向確保這些病患使用正確劑量考量。擴大使用抗VEGF治療也可大大降低CNV發病率，但此類治療的成本效益還不清楚。
Rein博士等人結論表示，應有更多努力以讓這些治療廣為CNV病患所用，且價格對使用者和製造者都很公平。
疾病控制與預防中心、糖尿病轉移小組支持本研究。作者宣告沒有相關財務關係。
Age-Related Macular Degeneration Prevalence Due to Explode by 2050
By Fran Lowry
Medscape Medical News
April 13, 2009 — The number of cases of age-related macular degeneration (AMD) will increase substantially between 2010 and 2050 in the United States as the population ages, according to the results of a simulation model of future AMD rates published in the April issue of the Archives of Ophthalmology. However, the use of antioxidant vitamins and other new therapies can reduce the resulting visual impairment and blindness by as much as 35%, researchers say.
"Newly discovered prophylactic and treatment therapies for AMD offer substantial improvements over past therapies and could potentially offset some degree of future AMD morbidity," write David B. Rein, PhD, from the Research Triangle Institute International in Research Triangle Park, North Carolina, and colleagues from the Vision Health Cost-Effectiveness Study Group. "If widely adopted, new AMD treatments could alter the future burden of the disease by delaying the onset of advanced AMD and by diminishing the visual impact of [choroidal neovascularization (CNV)]."
The goal of this study was to forecast the epidemiology of AMD in a variety of treatment scenarios up to the year 2050.
The investigators simulated cases of early AMD, CNV, geographic atrophy (GA), and AMD-attributable visual impairment and blindness using the following 5 treatment scenarios: (1) no treatment, (2) focal laser and photodynamic therapy (PDT) for CNV, (3) vitamin prophylaxis at early-AMD incidence with focal laser/PDT for CNV, (4) no vitamin prophylaxis followed by focal laser treatment for extra and juxtafoveal CNV and antivascular endothelial growth factor (anti-VEGF) treatment, and (5) vitamin prophylaxis at early-AMD incidence followed by CNV treatment, as in scenario 4.
In the vitamin prophylaxis scenarios, the investigators assumed individuals were treated with the Age-Related Eye Disease Study (AREDS)–recommended antioxidant vitamins plus zinc regimen.
The simulation model was based on the AREDS simplified scale.
In the model, cases of early AMD increased from 9.1 million in 2010 to 17.8 million in 2050 across all scenarios.
The use of vitamins did alter the number of forecasted cases of advanced AMD, reducing the number of cases by approximately 25% in scenarios 3 and 5.
Cases of visual impairment and blindness increased from 620,000 in 2010 to 1.6 million in 2050 in the absence of antioxidant vitamin and anti-VEGF treatment. However, this number was reduced by 2.4% in scenario 2, by 22.0% in scenario 3, by 16.9% in scenario 4, and by 34.5% in scenario 5.
The study has several limitations, the authors write. The simulation model attempts to use contemporary data to predict outcomes occurring in the distant future, but it does not account for future changes in treatment technologies that could alter forecasts of AMD and its consequences, and it assumes that the age-specific incidence of AMD and its progression will remain constant into 2050. "Although we have tried to mitigate the effect of uncertain data using sensitivity analyses," the authors write, "like all forecasts these should be treated as estimates that contain a good deal of embedded uncertainty."
Dr. Rein and colleagues also caution that little is known about the efficacy of anti-VEGF therapy beyond the 24 months observed in clinical trials. As well, the ability of anti-VEGF therapies to treat forms of CNV other than subfoveal CNV has not been shown.
The model also assumes complete compliance with current clinical recommendations for the use of antioxidant vitamins and anti-VEGF treatments. The reality is that patients are likely to use these therapies at substantially lower rates, the authors note.
They conclude that public prevention efforts should focus on expanding the use of antioxidant vitamins in people with early AMD. Such efforts should also go toward ensuring that these patients use the correct dose. Expanded use of anti-VEGF therapies is also highly likely to reduce morbidity from CNV, although the cost-effectiveness of such treatment is not yet known.
"Additional efforts should be made to make these treatments widely available to patients with CNV at a price that is fair to both the payer and the producer," Dr. Rein and colleagues conclude.
This study was supported by the Centers for Disease Control and Prevention's Division of Diabetes Translation. The authors have disclosed no relevant financial relationships.
Arch Ophthalmol. 2009;127:533–540. |
|
