Value-Based Medicine and Interventions for Neovascular Age-Related Macular Degeneration

Gary C. Brown, MD, MBA
Melissa M. Brown, MD, MN, MBA
Retina Service, Wills Eye Institute, Jefferson Medical College, Philadelphia, PA
Center for Value-Based Medicine, Flourtown, PA

Value-based medicine is the practice of medicine based upon the value (improvement in quality-of-life and length-of-life) conferred by healthcare interventions. A pillar of value-based medicine is the fact that patients should receive the interventions which deliver the greatest value. Very importantly, it should be noted that value in no way refers to cost, but rather solely the patient benefit conferred by an intervention. Only when the value of two or more interventions is similar does cost come into the equation; in this instance, the intervention of choice is the one which is less expensive.

The improvement in quality of life conferred by an intervention for neovascular age-related macular degeneration (ARMD) is measured using utility analysis, in which the anchors are 1.00 (permanent normal vision OU) and 0.00 (death). Utilities are calculated by first asking patients what proportion of their remaining life, if any, they would be willing to trade in return for normal vision permanently. This proportion is then subtracted from 1.0 to arrive at a time tradeoff utility. Thus, if a person with 20/100 vision is willing to trade 5 of 15 remaining years in return for permanent normal vision, the utility is (1.00 – 0.33 =) 0.67.  

The better the vision in the best-seeing eye, the higher the associated utility value. For example, the utility value associated with 20/20 vision in the best-seeing eye is 0.92, while that associated with 20/40 vision in the better eye is 0.80. Since ophthalmic interventions generally do not affect length-of-life, their value gain is equivalent to the improvement in quality-of-life.

If an intervention takes the vision from 20/40 to 20/20, the improvement in utility is (0.92 – 0.80 =) 0.12, or a 15% improvement in quality-of-life. Additionally, adverse effects associated with an intervention are integrated as disutilities which diminish the overall utility gain.

Value gain can also be measured in QALYs (quality-adjusted life-years) by multiplying (utility improvement) x (years of benefit). Thus, if the utility improves by 0.12 for 10 years, (0.12 x10 =) 1.2 QALYs are gained.

The cost paid per QALY can also be measured using the $/QALY (dollars expended per QALY gained). This $/QALY is referred to as the cost-utility ratio (cost-effectiveness ratio). By convention, therapies with a cost-utility ratio of < $50,000 are very cost-effective, while those costing > $100,000/QALY are not cost-effective.¹

The value of each therapy for neovascular ARMD can be readily quantified using value-based medicine. Case in point, the value gain (quality-of-life improvement) associated with photodynamic therapy (PDT) for the treatment of classic subfoveal choroidal neovascularization is 8.1%.²  For the treatment of occult lesions < 4 disc areas, the value gain (quality-of-life improvement) conferred by PDT is 6.3%. These numbers compare quite favorably to the use of statin drugs to prevent heart attack and stroke, which confer a 3.8% improvement in value, or biphosphonates for osteoporosis which confer a 1-2% value gain. Preliminary data suggest that the use of ranibizumab confers greater than a 15% value gain (improvement in quality-of-life).³ Thus, interventions for neovascular ARMD deliver an extraordinary degree of value compared to other common interventions in healthcare.

The cost-utility of PDT for the treatment of classic subfoveal choroidal neovascularization is $31,103, well within the confines of very cost-effective interventions. For occult lesions < 4 disc areas the cost-utility is $38,599. For reference, the cost-utility of most anti-hypertensive medication is in the range of $10,000/QALY, while the average cost-utility of the statin drugs for the treatment of hyperlipidemia is approximately $60,000-$70,000/QALY. 

In summary, value-based medicine analyses can quantify the conferred value (benefit) and cost-effectiveness of all interventions for macular degeneration using the same outcomes. Furthermore, the conferred value and cost-effectiveness of interventions for ARMD can be compared to the conferred value of interventions across all of healthcare, whether medical, surgical or pharmaceutical.¹

REFERENCES

1. Brown MM, Brown GC, Sharma S. Evidence-Based to Value-based Medicine. Chicago, AMA Press, 2005, pp 1-324.
2. Brown GC, Brown MM, Roth Z, Campanella J, Beauchamp GR. The cost-utility of photodynamic therapy in eyes with neovascular age-related macular degeneration. A reappraisal with 5-year data. Am J Ophthalmol 2005;140:679-687.
3. Brown MM, Brown GC. Value-based medicine and neovascular macular degeneration interventions. Presented the American Academy Retina Subspecialty Day, Las Vegas, November, 2006.