A validated, disease-specific quality of life measure for acoustic neuroma Brian Shaffer, M.D. February 26, 2009 Faculty discussant: Michael Ruckenstein, MD Otorhinolaryngology: Head and Neck Surgery.
Download ReportTranscript A validated, disease-specific quality of life measure for acoustic neuroma Brian Shaffer, M.D. February 26, 2009 Faculty discussant: Michael Ruckenstein, MD Otorhinolaryngology: Head and Neck Surgery.
A validated, disease-specific quality of life measure for acoustic neuroma
Brian Shaffer, M.D.
February 26, 2009 Faculty discussant: Michael Ruckenstein, MD
Otorhinolaryngology: Head and Neck Surgery at PENN Excellence in Patient Care, Education and Research since 1870
Acoustic neuroma
• Acoustic neuromas are the most common temporal bone neoplasms – CPA acoustic neuromas represent 10% of all intracranial tumors • Mortality rates are far less than 1%, but there is often considerable associated morbidity from the tumor itself or as a consequence of its treatment
Acoustic neuroma
• Majority of patients aged 40-54 – For many this represents a period of maximum family, social and occupational responsibility – Potential for significant disruption is large • Many studies focus on physical disability, but few examine psychosocial or economic impact
QOL with acoustic neuroma
• 1977: Medline adds “quality of life” as a keyword/MeSH heading • 1986, Lohne V et al: “I want to smile. How do individuals with facial paralysis resulting from surgical removal of an acoustic neuroma cope with daily living?” 15
QOL with acoustic neuroma
• Laryngoscope 1989: Wiegand and Fickel find a considerable discrepancy between the assessment of postoperative facial nerve function as judged by patients and their surgeons 35 – Surgeons generally underrated the functional disability – What followed was a large number of publications focusing on post-operative quality of life issues – Many continued to focus just on symptom reporting without QOL measures 1,9,10,22,25,28,30,32,34
QOL with acoustic neuroma
• Laryngoscope 1998, Nikolopoulos TP et al: investigate quality of life 1-3y after microsurgery 21
Generic vs. disease-specific scales
• Generic scales useful for making comparisons between different diseases and conditions • Disease-specific scales useful when disease or condition-related attributes need to be assessed, and when greater sensitivity to the clinical condition under consideration is required 4 – Facial nerve function/appearance, hearing, balance, etc.
• Often recommended to use both types of scales side by-side in order to address both clinical and broader policy questions 18
QOL with acoustic neuroma
• Many studies have embraced the SF-36 generic health-related QOL scale with varied results • Recognizing the limitations of a generic scale, authors have also designed and employed multiple different scales – Authors frequently use their own questionnaires – None of these instruments has been validated for acoustic neuroma patients
Assessing validity
• Validity is the degree to which a scale measures what it is intended to measure • This is challenging with QOL studies because the measurement of QOL factors depends on their definitions – These will typically vary from researcher to researcher and patient to patient
Validated QOL measures
• Why use validated scales?
• Example from psychiatric literature – Marshall (2000) reviewed 300 randomized controlled trials of schizophrenia 17 – Studies were 40% more likely to report that treatment was effective when they used unpublished scales rather than validated ones – 1/3 of claims of treatment superiority would not have been made if the studies had used published scales
Assessing validity
• Face validity: unambiguous and appropriate, appears to measure what is intended • Content validity: all relevant concepts covered • Criterion validity: correlation with gold standard – No gold standard exists for acoustic neuroma!
• Construct validity: hypothesis testing – Convergent validity: correlation with related indicators – Divergent validity: uncorrelated with unrelated indicators – Discriminative validity: discriminates different patient groups • Not as relevant in our study as not a screening tool – Exploratory factor analysis: confirm a subscale structure
Methods
• Our goal is to develop and validate a new disease-specific QOL measure for patients with a diagnosis of acoustic neuroma – Literature review and scale development – Application to patient cohort and chart review – Statistical analysis for validity testing and item reduction – Reliability testing
Devising items
• Critical literature review – Compendia of QOL scales – Focus on studies presenting open-ended questionnaires 2,13,20,24,28 • Face and content validity assessed by internal and external expert review – Face validity: low ready level, consistency in wording (positively worded), items of short length – Content validity: all relevant domains appear covered from an otology and psychosocial perspective, and all domains from open-ended questionnaires addressed
Devising items
• Bateman N et al (2000) compiled 279 responses from 53 questionnaires, and presented responses using patients’ actual wording 2
Devising items
• Survey results from the Acoustic Neuroma Association (Ryzenman 2004) asked patients to identify the “most difficult aspect” of their acoustic neuroma experience 28
Preliminary survey
• The preliminary survey was an 88 question self administered survey – 80 bipolar Likert items (strongly disagree, disagree, neutral, agree, strongly agree) – 8 visual analogue scale (VAS) items meant to assess global quality of life in various domains – Included a modification of the Hospital Anxiety and Depression Scale (HADS), a reliable and valid screen for anxiety and depression 36 • Domains covered included hearing, balance, facial/eye symptoms, activities of daily living, pain, anxiety/depression, energy/vitality, general health
Data collection
• IRB approval obtained • 262 patients contacted via mail with packet that included: – Introductory letter – Informed Consent and HIPAA consent request – Preliminary survey copy – SF-36 copy • 117 returned, complete surveys with proper consents – Complete response rate of 45% • Chart review completed, recording: – Demographics, audiogram results, tumor size, treatment plan, House-Brackmann facial nerve score, years since diagnosis, and years since treatment.
Data collection
Patient Demographics and Disease Characteristics Age, years Range Gender, N (%) Male Female Years since diagnosis Treatment, N (%) Conservative Surgery Gamma Knife Years since treatment Tumor size, mm Range House-Brackmann score, N (%) I II III IV V VI Pure-Tone Average, dB Speech Recognition Threshold, dB Speech Discrimination Score, % Cases (N=117) 60.4
20-84 55 (47) 62 (53) 5.5
59 (50) 48 (41) 10 (9) 5.1
16 2-60 74 (81) 5 (6) 8 (9) 2 (2) 2 (2) 0 (0) 57 55 41
Psychometric analysis
• Start with a broad initial survey with built-in redundancy, then apply stepwise item reduction strategies – 1. Eliminate items with high floor/ceiling effects – 2. Eliminate items with low item-total correlation – 3. Eliminate items with high item-item correlation – 4. Exploratory factor analysis, eliminating items with ambiguous subscale structure
Frequency of Endorsement
• Items with very low/high endorsement (i.e. floor/ceiling effects) are not sufficiently informative and do not respond well to change – Items with a floor or ceiling effect of >0.7 were eliminated 6,8 – Resulted in elimination of 5 items
Item-Total Correlation
• Measure of internal consistency • Examine correlation of each individual item score with the scale total – Items with Item-Total correlations < 0.4 discarded 11,31 – Resulted in elimination of 18 items
Item-Item correlation
• Very high correlations between different items suggests redundancy • For item pairs with item-item correlations > 0.7, the item with the lowest item-total correlation was eliminated 8,11 – Each pair was inspected to ensure that the items did appear to be measuring similar attributes – Resulted in elimination of 18 items • 42 items remained at this stage
Exploratory factor analysis
• Significance tests play a far less important role in multivariate analysis than in univariate analysis – With measurement scales, each item becomes a unique variable, giving 42 variables in our system!
• The main emphasis is put on finding natural groupings of questions – Exploratory factor analysis is a powerful method of demonstrating these groupings
Exploratory factor analysis
• Factor analysis seeks to combine variables (i.e. questions) into a smaller number of “principal components” – or groups – that are still informative – Explores the dimensionality of the scale • This then allows one to identify an underlying structure to the data (i.e. subscales) – Individual items will typically fall within one of the different subscales
Exploratory factor analysis
• Confirms that items and/or groups of items are measuring what they were intended to measure – Items that group with more than one subscale or that group with the “wrong” subscale are ambiguous and should be eliminated 12,31 • Our analysis identified a natural 7-factor/group solution and eliminated 14 ambiguous items – Leaving a final 28-item survey – That these purely statistical groupings make sense to the knowledgeable reader supports the validity of the scale
Item 54 56 60 64 70 26 27 29 66 76 78 11 12 13 15 18 21 3 6 10 67 47 59 71 72 74 75 48 Exploratory Factor Analysis for 28 Remaining Items Component Item Description Get frightened feeling Worrying thoughts "Butterflies" in the stomach Sudden feelings of panic Difficulty falling/staying asleep Problems moving face Eye discomfort/tearing Speech affected by face Decreased sexual drive Health is excellent Expect health to get worse Dizziness Unsteady Whirling/falling when walking Difficulty changing directions Trouble walking in dark Afraid of appearing intoxicated Hearing loss Difficulty in conversations Tinnitus Isolation Accomplish less Feel slowed down Difficulty concentrating Impatient Lacking energy Memory Head pain 1 0.75
0.55
0.75
0.70
0.45
2 0.86
0.60
0.77
3 -0.56
-0.65
-0.69
4 -0.63
-0.83
-0.68
-0.77
-0.58
-0.60
5 0.73
0.71
0.52
0.61
0.77
Cronbach's alpha value 0.78
0.69
0.65
Rotation method: Varimax with Kaiser normalization.
For clarity only the factor loadings of greatest magnitude are shown.
NA = not applicable with only one item 0.86
6 -0.54
-0.59
-0.61
-0.69
-0.64
-0.74
0.88
7 0.76
NA
Scoring
• Item scores transformed and calculated on a scale of 0 to 100 (worst to best QOL) • Domain/group scores similarly calculated as average of component item scores • Total score an equal average of individual domain/group scores – An overall weighted total to reflect difference in number of items in different domains
Scale and Domain Distributions
Scale and Domain Distributions
Hearing Balance Face/Eye Anxiety Energy Pain General Total Mean 65.4
72.3
83.9
72.7
68.4
76.5
64.4
71.9
Domain and Total Score Distributions Median 68.9
75.0
91.7
75.0
67.5
75.0
66.7
74.2
Standard Deviation 22.4
20.0
20.2
20.0
22.7
28.5
20.1
15.3
Skewness -0.30
-0.40
-1.40
-0.60
-0.30
-1.10
-0.20
-0.40
% Floor 0 0 1 0 0 3 0 0 % Ceiling 8 13 46 11 14 47 5 0 • Face/Eye and Pain scales skewed secondary to ceiling effects – As long as endorsement rate < 95% and modest item-item correlations (>0.25), this will not affect the psychometric properties of a scale 37,38
Distributions by demographics
Correlation/Distribution of Scale Domains by Demographics Gender* f m Age** Years since Dx** Scale Anxiety Balance General Hearing Energy Pain Eye/face 70.8
70.7
63.8
67.4
70.1
77.0
82.5
74.4
74.5
64.5
62.5
66.2
75.5
87.0
-0.10
-0.21
-0.31
0.03
-0.24
0.03
-0.11
-0.06
-0.14
-0.18
-0.20
-0.14
-0.06
-0.24
Total 71.8
72.1
-0.18
-0.21
*No signficiant differences in mean scores using ANOVA.
**Correlations are Pearson product-moment correlation coefficients.
Years since Rx** 0.09
0.00
-0.04
-0.06
-0.06
-0.04
-0.16
-0.06
Correlations between domains
Correlations Between Scale Domains Anxiety Balance General Hearing Energy Pain Eye/face Anxiety 1.00
Balance 0.51
1.00
General 0.49
0.41
1.00
Hearing 0.47
0.50
0.39
1.00
Energy 0.61
0.61
0.59
0.60
1.00
Pain 0.40
0.34
0.28
0.37
0.42
1.00
Eye/face Total* 0.30
0.66
0.41
0.65
0.10
0.52
0.31
0.62
0.33
0.76
0.23
0.47
1.00
0.37
*Modified total scores that exclude individual domain contributions used for correlations.
Correlations are Pearson product-moment correlation coefficients.
Convergent validity
• Can investigate correlation with SF-36 and global visual analogue scale (VAS) measures • Other potential indicators more problematic – Size: no difference in QOL 5,10,20,24,29,30,33 – H-B: variable to no impact 7,10,13,14,20,29 – PTA/SRT/Discrimination scores: variable to no impact perceived symptoms or QOL 39 20 – Balance function tests: do not correlate well with patient – Surgery: some patients had deterioration, others large improvement in health status, large changes over time 23,24,29 – Gamma knife: some trends towards deterioration, not statistically significant 29 – Time since surgery: variable to no effect 20,33
Scale/SF-36 correlations
Correlations Between Scale Domains and SF-36 Domains Individual SF-36 Domains Anxiety Balance General Hearing Energy Pain Eye/face Physical Functioning 0.28
0.49
0.47
0.34
0.55
0.29
0.17
Role Physical 0.35
0.48
0.51
0.53
0.53
0.40
0.17
Role Emotional 0.31
0.28
0.43
0.38
0.51
0.28
0.01
Vitality 0.57
0.55
0.55
0.49
0.69
0.43
0.24
Mental Health
0.59
0.47
0.46
0.50
0.57
0.34
0.16
Social Functioning 0.44
0.51
0.41
0.51
0.58
0.28
0.16
Total 0.53
0.61
0.45
0.72
0.63
0.58
Correlations are Pearson product-moment correlation coefficients.
Stronger relationships are shown in bold.
Pain 0.25
0.30
0.42
0.29
0.39
0.42
0.20
0.47
General Health 0.39
0.42
0.61
0.35
0.56
0.37
0.19
0.59
Total Score 0.47
0.57
0.62
0.52
0.70
0.43
0.20
0.71
Scale/SF-36 correlations
•Correlation of total scale score with SF-36 Physical Health and Mental Health Subscale
Scale/VAS correlations
Correlations Between Domains and Visual Analog Scale (VAS) Items Individual VAS Items Domains Anxiety Balance General Hearing Energy Pain Eye/face Total Overal QOL 0.47
0.37
0.60
0.35
0.42
0.21
0.07
0.49
Facial Dizziness Function 0.37
0.27
0.66
0.32
0.35
0.50
0.26
0.22
0.54
0.40
0.17
0.22
0.26
0.03
0.46
0.34
Emotional Health
0.60
0.52
0.42
0.45
0.58
0.24
0.23
0.61
Hearing 0.29
0.38
0.24
0.54
0.40
0.15
0.09
0.42
Pain 0.33
0.36
0.43
0.34
0.37
0.43
0.16
0.50
Correlations are Pearson product-moment correlation coefficients.
Stronger relationships are shown in bold.
ADLs 0.43
0.56
0.47
0.46
0.58
0.47
0.29
0.66
Energy 0.53
0.58
0.55
0.56
0.72
0.35
0.20
0.71
House-Brackmann score
Distribution of Scale and SF-36 Domain Scores by House-Brackmann Score II House-Brackmann Score III IV V I Scale Anxiety Balance General Hearing Energy Pain 73.7
74.5
62.5
64.2
68.7
75.0
Eye/face Total SF-36 Physical Functioning 89.8
72.6
Role Physical Role Emotional Vitality Mental Health 76.2
80.7
81.1
68.6
80.0
Social Functioning Pain General Health 86.4
82.3
71.5
Significance testing by ANOVA NA = Not applicable (N=0) 69.0
55.8
60.0
61.3
56.7
75.0
65.0
63.3
65.6
80.0
93.3
65.0
77.6
82.5
85.0
73.0
66.9
70.3
74.0
65.6
64.1
84.4
63.5
69.8
78.5
96.9
100.0
69.4
77.5
89.1
88.1
63.8
85.0
79.2
79.2
78.1
81.3
100.0
70.8
81.9
94.4
100.0
100.0
87.5
86.0
100.0
100.0
87.5
72.5
85.4
75.0
62.5
89.6
100.0
66.7
78.8
91.7
100.0
100.0
75.0
90.0
100.0
100.0
90.0
VI NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA p<0.001
Audiogram results
Correlation of Scale and SF-36 Domains with PTA, SRT and Speech Discrimination Scores PTA SRT Discrim Scale Anxiety Balance General Hearing Energy Pain Eye/face Total SF-36 Physical Functioning Role Physical Role Emotional Vitality Mental Health Social Functioning Pain General Health 0.03
-0.04
-0.02
-0.20
-0.11
0.02
-0.23
-0.11
-0.03
-0.01
0.02
-0.03
0.01
0.00
0.08
-0.03
0.06
-0.04
-0.02
-0.18
-0.11
0.04
-0.23
-0.09
-0.05
0.00
0.03
-0.02
0.01
-0.01
0.08
-0.04
-0.05
0.04
0.03
0.16
0.08
0.03
0.15
0.09
-0.03
-0.02
-0.12
-0.06
-0.07
-0.14
-0.04
-0.01
Correlations are Pearson product-moment correlation coefficients.
Size
Distribution of Scale and SF-36 Domain Scores by Size <1 Scale Anxiety Balance General Hearing Energy Pain Eye/face Total SF-36 Physical Functioning Role Physical Role Emotional Vitality Mental Health Social Functioning Pain General Health Significance testing by ANOVA 71.5
77.4
80.2
79.8
68.1
79.0
85.2
82.4
70.1
73.1
62.2
64.2
68.6
77.3
87.2
71.8
Size (cm) 1-2 77.0
76.0
62.8
68.9
68.3
75.7
89.5
74.0
75.8
84.5
89.7
70.1
81.5
86.4
86.2
67.6
>2 72.0
69.4
70.6
62.3
70.8
80.8
77.2
71.9
86.1
88.3
93.3
70.8
80.8
91.5
87.8
79.8
p=0.01
p<0.05
Treatment
Distribution of Scale and SF-36 Domain Scores by Treatment Type Treatment Conservative (n=54) Scale Anxiety Balance General Hearing Energy Pain Eye/face Total SF-36 Physical Functioning Role Physical Role Emotional Vitality Mental Health Social Functioning Pain General Health Significance testing by ANOVA 72.2
75.5
60.8
66.6
69.2
77.8
92.3
73.5
77.8
84.2
84.6
70.6
80.6
86.8
83.2
71.6
Gamma (n=10) 74.0
72.5
54.2
63.1
66.7
80.0
85.8
70.9
68.3
60.0
83.3
69.0
81.6
81.9
73.8
58.0
Surgery (n=48) 73.4
70.1
69.7
64.2
68.7
77.1
77.8
71.6
81.1
86.5
88.2
67.5
79.2
88.1
88.5
75.5
p<0.03
p<0.001
p<0.05
p<0.05
Discriminative validity
• Our scale is not intended as a diagnostic or screening tool like some in the psychiatric literature – Do not expect difference between similar groups of patients • The scale was given to a group of patients presenting to a general otology clinic for comparison
Discriminative validity
Comparison of Scale and SF-36 Domains Between Cases and Controls Age, years Range Gender, N (%) Male Female Scale Anxiety Balance General Hearing Energy Pain Eye/face Total SF-36 Physical Functioning Role Physical Role Emotional Vitality Mental Health Social Functioning Pain General Health *Using Student's t-test NS = not significant Patients (n=117) 60.4
20-84 55 (47) 62 (53) 72.3
72.5
64.2
65.1
68.3
76.3
84.6
71.9
78.7
83.3
86.6
69.1
80.2
87.1
84.4
72.2
Controls (n=90) 52.3
16-90 44 (51) 43 (49) 66.0
68.1
60.9
61.2
60.7
75.3
93.8
71.3
75.1
65.9
78.2
65.7
76.9
74.7
84.9
64.3
p value* p<0.001
NS NS NS p<0.05
NS NS NS p<0.03
NS p<0.001
NS NS NS NS NS NS p<0.001
NS p<0.03
Reliability
• Reliability: the scale is measuring
something
in a reproducible fashion • Different ways to measure – Internal consistency: based on single administration • Cronbach’s alpha results already shown • Factor structure also supports reliability – Stability: test-retest reliability • Part of the ongoing study
Conclusions
• There is a need and demand for a validated, disease-specific QOL measure for acoustic neuroma • Our QOL measure has validity in terms of face, content, and construct properties • Internal consistency as one measure of reliability is strong – Test-retest reliability studies are ongoing
Conclusions
• Use of the survey as part of ongoing prospective trials will ultimately do much to prove its validity – Show sensitivity to change over time – Show changes from before/after intervention
References
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Special thanks: Michael Ruckenstein, MD Douglas Bigelow, MD Jeffrey Staab, MD
Otorhinolaryngology: Head and Neck Surgery at PENN Excellence in Patient Care, Education and Research since 1870