University of Minnesota Medical Technology Evaluation and Market Research Department of Healthcare Management Course: MILI/PUBH 6589 Spring Semester, 2013 Stephen T. Parente, Ph.D. Carlson School of Management, Department of Finance

Class Overview Measuring Effectiveness  Health state 101  Specifying clinical outcomes  Measuring outcomes  Use of decision trees in effectiveness analysis

Terminology: “Health State” “The health of an individual at any particular point in time.” [Gold et al 1996]

When Considering an Assessment of Health: Two areas of concern Length of life –mortality rates –life expectancy Quality of life –ability/disability –independence –other aspects of health & well-being

1.quality of life 2.combination of quality & length We need measurement scales for What do we mean by “measurement” of outcomes?

Measurement Process of setting up a correspondence between –Some set of things (here health states) –Numbers So that qualitative relations among the things (such as “better than”) are reflected by the quantitative numerical relationships

Some differences in scales matter; some don’t Pain ratings from 6 people: A,B,B,B,C,D Averages on 3 different scales:

Goal of health outcome measurement Assign scales so that when we do arithmetic, the averages work out the way we think they should. Use common vales to permit apples to apples comparison.

How about a single measure that combines morbidity & mortality? Simple idea: Weight each year of life with a measure of degree of good/poor health. Add up the weighted life years.

DeadExcellent OverallHealth Quality additional years of life nowdeath QALYs = area under this curve QALE = average number of QALYs experienced by a cohort of the same starting age and quality of life of the same starting age and quality of life = best estimate of future health-adjusted life years for = best estimate of future health-adjusted life years for random member of the cohort random member of the cohort “Life Path” = the general health outcome

Mathematical Assumption to make QALY tractable: “Q” weighting is separable from duration of the health state it represents and other health states in the life path –simplifies data collection immensely! –Life expectancy obtained from medical data –combined mathematically instead of by judgment

Issues... What aspects of “health” are normally covered in a health-related quality of life (HRQOL) measure? How is a health classification system operationalized? How are numbers (weights) assigned to health states?

Illustrate with several different measures QWB Quality of Well-being scale HUI Health Utility Index YHL measure in Years of Healthy Life EQ-5D EuroQol health status measure SF-36 Questionnaire-based health profile

Dead Excellent Overall HRQOL additional years of life nowdeath Continuum of health state weights

Death Excellent Overall Health Description system covering all health states Numerical scale Function corresponding states to scale values so arithmetic “works” Health Status Measurement System

“The health of an individual at any particular point in time.” Things “health” might include... –Functional abilities? Which ones? –Pain? –Other?  “Dimensions” of Health

Typical Concepts & Domains Health Perceptions Social Function –Soc. relations –role function –intimacy –communication Impairment –sensory function/loss –symptoms Psychological Funct. –Cognitive –emotional –mood/feelings Physical Function –mobility –physical activity –self-care

A Hierarchy of Health Dimensions

Health states are multidimensional Measure as vector –one number for each dimension Create one summary number

State 1 –intermittent moderate pain –no mobility limitations –able to do normal socio-occup. functions State 2 –continuous mild pain –mobility limitation –some occupational restrictions Example

Profile (“vector”) representation 1. Decide what dimensions 2. Develop scales for each dimension 3. Develop process for locating patients on each dimension PF SF P A = (70, 30, 50) B = (55, 60, 90) Physical Function Social Function Pain A B

Single number (“scalar”) representation: 1. Same steps as for a profile +2. Develop process for aggregating the attributes into one summary number. OR Just do direct aggregate scaling State B State A Perfect health dead

Example classification scheme: YHL Functional ability

Example classification scheme: YHL 5 levels of self-rating x 6 levels of function = 30 health states An intermediate health state BestWorst

An intermediate health state BestWorst Scaling the Health States: 1.0 Dead 0.0??

Weights for YHL Functional ability Note: “dead” = 0.00

Definitions ….. HALYs: health-adjusted life years using a health status measure for health weights –QALYs: quality-adjusted life years … a type of HALY computed using a HRQOL measure for health weights.

Disease SpecificGeneral Health non-preference physical measures Many! e.g. joint counts total cholesterol -- rating scales Many! SIP, Rand GHS, COOP, MOS short forms EVGFP preference based indexed? QWB, HUI, EQ-5D, YHL? patient’s own prefs.ad hoc

Disease-specific instruments Very specific to intended effects of treatments Can be sensitive to small changes in disease activity/status Clinicians can link to specific actions

But disease-specific measures may miss things Many treatments have unintended effects (arthritis & hearing) Many people (especially when older) have multiple health conditions (median number is 3)...

Why an interest in measures of General Health? (aka “generic measures”) Allows many comparisons: –across diseases –in people with multiple conditions –across studies Needed for cost-effectiveness studies

Medical Outcomes Study -- “short forms” Derived from Rand General Health Survey Originally 250+ questions Published short forms that are in use: –SF-12 –SF-20 –SF-36

SF-36 8 components, scaled worst=0 to best=100  Physical functioning  Role function (from physical limitation)  Pain  General Health Perception Mental health  Vitality  Social functioning  Role function (from emotional limitation)  Mental health

New Scaling for SF-36 & SF-12 PCS : physical component scale MCS: mental component scale

Two web sites for SF

Decision Tree Overview: Movement Across Health States Over Time

What’s Next? Break Technology Evaluation Roundtable Projects