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STATISTICS 542STATISTICS 542Intro to Clinical TrialsIntro to Clinical Trials

Quality of Life AssessmentQuality of Life Assessment

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Why Are We InterestedWhy Are We Interested in the Quality of Life? in the Quality of Life?

The United States Food and Drug Administration has stated that efficacy with respect to overall survival and/or improvements in QOL might provide the basis for drug approval

“Live longer – feel better”

Shaughnessy JA, Wittes RE, Burke G et al. Commentary concerning demonstration of safety and efficacy of investigational anticancer agents in clinical trials. J Clin Oncol 1991; 9:2225-32.

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Outline for Outline for Quality of LifeQuality of Life

• General background

• Data collection considerations

• DeMets’ Perspective

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Your Quality of LifeYour Quality of Life

How are you feeling this afternoon?

Mood Happy Miserable

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What is Quality of Life?What is Quality of Life?

WHO: “Health is not only the absence of infirmity and disease, but also a state of physical, mental and social well being

Multiple domains include: physical, cognitive, emotional and social functioning, pain, sexual functioning, health perceptions, and symptoms such as nausea and fatigue

Fundamental principle: quality of life is assessed by the patient

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Quality of Life (1)Quality of Life (1)

• Definition depends on contextCancer vs. MI vs. hypertension

• Some instruments are disease specific

• Others are "general health status" instruments– POMS = Profile of Mood– SIP = Sickness Impact Profile

• Difficulties with concept– No agreement on definitions– Lack of standardized measures

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Quality of Life (2)Quality of Life (2)• One definition (Levine & Croog)

Two Components

- Functioning1. Social (Major component)

- Get along with family & friends | sense of worth2. Physical

- Perform daily life activities3. Emotional

- Stability and self control4. Intellectual

- Decision making ability

- Perceptions1. Life Satisfaction

- Sense of well being2. Health Status

- Compared to others

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Factors Which Influence Factors Which Influence Quality of LifeQuality of Life

1. Intervention

2. Disease Process

3. "Labeling" Need a control group

- Diagnosis brings on change

4. Concomitant Care

5. Non-related life events

(e.g. death in family)

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Rationale in Clinical TrialsRationale in Clinical Trials

• Quality of life may assess effect of intervention

– primary response (treatment less toxic?)– side effects (treatment toxic?)– economic aspects (low risk/cost

treatment but benefit high?)

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How To Assess Quality of LifeHow To Assess Quality of Life

• Determine your QoL Objective

• Choose an instrument– Reliable, valid, responsive, feasible– Global measures, disease-specific measures,

symptom checklists

• Select your assessment time points and administration format

• Develop an analysis plan

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Data Collection Considerations (1)Data Collection Considerations (1)

• Mode– Self-administered

• glasses, reading skills, fine-motor skills

– Personal interview• training/background of interviewer• sensitivity to gender/ethnicity/age• hearing impairment

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Data Collection Considerations (2)Data Collection Considerations (2)

• Content– instrument validity, sensitivity &

specificity – sensitivity of questions– frame of reference for answers

(cognitive skills, privacy, cultural background)

• Source(s)– participant, family or support network,

health care providers

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Off the Shelf Instruments

• Off-the-shelf instruments– Designed to distinguish sickness from wellness– May not be sensitive to particular aspect of a given

trial– May not be validated or "normed" in population

being tested– May ask ridiculous questions for trial pop.– May take hours to complete– May impact negatively on compliance

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Off-the-Shelf InstrumentsOff-the-Shelf Instruments(Example-NOTT)

• Design– Advanced Chronic Obstructive Pulmonary

Disease

– 24 vs. 12 hours of O2

– Quality of life 10 outcome (No norms in this pop!)

• Quality of Life Results – Patients were sick– Patients got worse– No treatment difference

BUT– Mortality ratio was 2/1 (p<.01)

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DeMets’ PerspectiveDeMets’ Perspective

• "Tailor Made" Instruments

– Can be Quick and simple

– Standardized but targeted to disease

– Must be Validated for trial population

– Select subsets of off-the-shelf instruments

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DeMets’ PerspectiveDeMets’ Perspective

• “Home-made" Instruments

– Often designed by a graduate student

– Often too long

– Often not validated or field tested on

your patient population

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Quality of Life Instruments Quality of Life Instruments

• Can be simple and short

• Classic examples for– Cancer– Congestive Heart Failure

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Quality of Life AnalysisQuality of Life Analysis

• Analytic methods likely to be based on a scoring system

• Methods often rank based

• Challenging to design/ compute sample size