If a person is otherwise young and healthy and a drug costs $10,000 per year, then the QALY is $10,000.
If a patient is older and has a chronic condition, then that patient’s utility may be defined as exactly half that of a young and healthy person. In that case, the QALY is $20,000 for the same drug.
If the patient is old and has two or more chronic conditions, then the patient’s utility could be defined as 25% that of a young and healthy person. In that case, the QALY IS $40,000 per year of life saved
Time Trade Off (TTO): Respondents are asked to choose between remaining in a state of ill health for a period of time, or being restored to perfect health but having a shorter life expectancy.
This trade off can be considered the presentation of a "happy pill" guaranteed to give you perfect health for a period of time after which you drop dead while you can have twice as long to live but you have to put up with a chronic illness.
Standard gamble (SG): Respondents are asked to choose between remaining in a state of ill health for a period of time, or choosing a medical intervention, which has a chance of either restoring them to perfect health, or killing them.
Very few patients, when faced with this actual choice, decide to avoid the treatment. However, comparative effectiveness analysis often disallows a choice by rationing the treatment for older age groups, or those in need of expensive medical interventions.
Visual Analogue Scale(VAS): Respondents are asked to rate a state of ill health on a scale from 0 to 100, with 0 representing death and 100 representing perfect health.
Patients can suffer from untreated depression that will reduce their definition on the scale. Those who are healthy can define artificially low values because of a lack of understanding of a disease state.
Since Avastin is given in combination with other drugs (specifically 5FU, Leucovorin, and oxiliplatin for colon cancer), it is difficult to investigate adverse events of just Avastin alone separate from the adverse events of the other drugs.
The market basket analysis demonstrates this inter-connectedness through a link graph showing how individual reports provide multiple drugs as possible causes.
The Adverse Event Report System (AERS) sponsored by the CDC (Centers for Disease Control) is a means of providing voluntary reports of adverse events after a drug is approved for use. It is located at http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Surveillance/AdverseDrugEffects/default.htm
For the year 2009, there are over 5000 reports related to the first-line treatment for metastatic colon cancer.
There are 4 discernable patterns for complaints concerning the drugs used for first-line treatment of metastatic colon cancer. There are a handful of reports that do not fit one of these four patterns.
Patricia Cerrito, PhD, Professor of Mathematics at the University of Louisville, has spent over 20 years investigating health outcomes using data mining tools. She has published a number of books on the general topic including
Cases on Health Outcomes and Clinical Data Mining: Studies and Frameworks
Text Mining Techniques for Healthcare Provider Quality Determination: Methods for Rank Comparisons