Clinical And Economic Outcomes Of Cancer Care 21 Health Care Outcome Measures

Response and survival often represent the primary clinical endpoints in clinical trials for the assessment of efficacy upon which sample size and power calculations are based.

Alternatively, clinical outcome can be measured in terms of life expectancy or the average number of years of life remaining at a given age. The life-years of an individual can be thought of as representing the area under the corresponding survival curve (26). The gain in life expectancy or life-years saved with treatment represents the marginal efficacy and can be thought of as the area between the survival curves with and without intervention. This method is more powerful for assessing treatment effect than for comparing median survivals or the event-free proportion at a given time. Changes in life expectancy are often used in economic analyses to express the efficacy of treatment.

The assessment of health care outcomes beyond traditional clinical measures of efficacy has become a focus of research. Alternative measures of interest include health-related quality-of-life (HRQOL) and economic outcomes. HRQOL can be assessed either through various health-profile measures or by the global assessment of patient preferences. Health profiles derived from psychosocial theory attempt to assess HRQOL through one of a variety of scales addressing the relevant dimensions, such as functional ability, emotional well-being, sexuality/intimacy, family well-being, treatment satisfaction, and social functioning (27). Alternatively, utility measures derived from economic and decision theory attempt to assess HRQOL by eliciting patient preferences for specific outcome states (28). Patient preferences can be assessed through a time tradeoff method incorporating a standard reference gamble generating a single value of health status along a linear continuum from death to full health.

The major advantage of measures of patient preference or utility is that they can be used to adjust measures of longevity such as life expectancy, e.g., the quality-adjusted life-year (QALY). The QALY represents the time in full health considered by the patient to be equivalent to actual time in the diseased state. Serial measurement of patient preferences over time can be used to estimate the cumulative impact of treatment on HRQOL. The sum over all health care states of the product of the time spent in each state and the utility associated with the state will yield the quality-adjusted time without symptoms of disease or toxicity of treatment (Q-TWIST) described by Gelber et al. (29). The assessment of HRQOL in conjunction with conventional clinical efficacy measures in clinical trials has gained increasing interest over the past few years (30,31).

How to Stay Young

How to Stay Young

For centuries, ever since the legendary Ponce de Leon went searching for the elusive Fountain of Youth, people have been looking for ways to slow down the aging process. Medical science has made great strides in keeping people alive longer by preventing and curing disease, and helping people to live healthier lives. Average life expectancy keeps increasing, and most of us can look forward to the chance to live much longer lives than our ancestors.

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