Transcript PowerPoint Presentation - University of Sheffield

DEVELOPMENT OF A PREFERENCE-BASED, CONDITION SPECIFIC PATIENT
REPORTED OUTCOME MEASURE FOR USE WITH VENOUS ULCERATION
1Sheffield
Simon Palfreyman1, John E Brazier2
Teaching Hospitals NHS Foundation Trust/ ScHARR, University of Sheffield, 2 ScHARR, University of Sheffield
Contact: Simon Palfreyman Email: [email protected]
Tel: 44 (0)114 2222 991
www.shef.ac.uk/heds
Introduction
Background
The SPVU-5D is a new condition-specific preference-based
measure of health related quality of life for use in the assessment
of the impact of venous ulceration.
It has five dimensions
encompassing physical, psychological and social aspects. The
measure was developed from the bottom-up and incorporates
items generated from patients. The measure has been shown to
have good practicality and validity. Preference-weights and a
scoring algorithm were produced based on valuations from the UK
population.
• Venous ulcers are non-healing wound on the lower leg that have been present for > 6weeks.
• They are more prevalent in the elderly and women but can also occur in illicit intra-venous drug users.
• The underlying cause is thought to be damage to the valves in the veins which results in venous
hypertension leading to restricted oxygenation and eventually to tissue damage.
• They account for 1.3% of the UK health budget cost the NHS between
• In the US result in the loss of approximately two million work days per year.
• The main treatment is by the application of compression bandages which have to be worn
continuously until the ulcer is healed.
• Healing times can vary from several weeks to many months, and some ulcers never achieve healing.
PICTURE OF A VENOUS LEG ULCER
Development of SPVU-5D
GRAPH OF OBSERVED VS PREDICTED VALUES FOR HEALTH STATES
1. Generation of items and descriptive system
1.000
Methods
Bottom-up approach used. Qualitative interviews and focus groups conducted with patients and clinical staff. Interviews
taped and transcribed. Framework analysis used to identify themes and issues. A selected sample re-interviewed to check
interpretation and ensure data saturation achieved.
Results
• Thirty-one interviews and one focus group conducted. Three main themes identified related to symptoms, social
restrictions and attribution.
• A total of 12 items identified for inclusion in PROM
3. Valuation of the health states
Methods
Fractional factorial design used to select 26 health states from the 720 described by the PROM for valuation using time
trade-off (TTO). Interviewer administered to 160 member of the UK general public. In addition, a discrete choice
experiment (DCE) using a postal survey of pair-wise choices was administered to 200 patients and 160 members of the
general public.
Regression models were used to predict health states and these compared with results from obtained from the valuations.
Results
• TTO produced logical ordering of health state values (best to worse).
• Predicted and observed values for health states in TTO showed strong correlation.
• Algorithm from regression models compared well with existing studies.
• DCE confirmed adaption of patients to health states by showing higher values for worse states than given by the general
public.
0.800
0.700
0.600
value
2. Testing and Refinement of the Instrument
Methods
The draft questionnaire sent to 266 patients with a history of venous ulceration. Item performance assessed on the basis
of predefined criteria (missing data of over 10%, presence of floor or ceiling effects and poor sensitivity). Factor and Rasch
analysis (RA) performed on questionnaire responses to identify poorly performing items.
Results
• Response rate of 57% obtained (n= 152).
• 4 items (personal care, personal relationships, social isolation and clothes) dropped due to poor item performance
including poor completion rate and floor/ ceiling effects
• Factor analysis showed that the 12 item questionnaire had some evidence of construct validity.
• Rasch analysis showed that two items (leisure and smell severity) showed little to no spread at logit zero. The items with
the widest spread were pain frequency (0.74), mood frequency (0.73) and mobility frequency (0.6).
• Final questionnaire (the SPVU-5D) consisted of five items with between three and five levels: pain frequency (4 levels),
mobility frequency (4 levels), mood frequency (5 levels), smell frequency (3 levels), and social isolation (3 levels)
0.900
Observed Values
Predicted Value
0.500
0.400
0.300
0.200
0.100
0.000
most to least severe health state
Acknowledgements
FURTHER DETAILS:
Palfreyman SJ et al (2007) Impact of intravenous drug use on quality of life for patients with venous ulcers. Journal of Advanced Nursing 58(5), 458–467
Palfreyman SJ et al. (2007) Development of a tool to examine the effect of venous ulcers on patients’ quality of life. Nursing Standard 21 (45), 57-69
Palfreyman, S. (2008) Assessing the impact of venous ulceration on quality of life. Nursing Times; 104: 41, 34–37.
Palfreyman SJ et al. (2010) Assessing current health related quality of life questionnaires administered to patients with venous ulcers: can they be used in
economic evaluations? Journal of Clinical Nursing 19 (5)892-97
Palfreyman SJ, Tod AM, Brazier JE, Michaels JA (2010) A systematic review of health related quality of life instruments used for people with venous ulcers:
an assessment of their suitability and psychometric properties. Journal of Clinical Nursing 19 (19/20); 2673-2703