Introduction: non-small-cell lung cancer
Decision problem: evaluation of different NSCLC therapy options
Research question: identification and weighting of the decision criteria
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Identification: What are the key decision criteria for the selection of an optimal NSCLC therapy from the patients’ perspective?
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Weighting: How do patients weight these different decision criteria when selecting the optimal NSCLC therapy?
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Subgroup: Are there differences in weighting of the relevant decision criteria for different groups of patients?
Objective: scientific evidence of patients’ perspectives
Decision-making context: burden of disease and treatment alternatives
Burden of disease: prevalence and incidence
Treatment (alternatives)
Methods and study design: elicitation of patient preferences
Discrete-choice experiments
Study design
Decision model:
Attributes and levels
Data collection plan, sample size, stratification and recruitment
Ethical considerations
Data collection: instrument, elicitation technique, tasks and experimental design
Experimental designs
Data analysis: data structure, statistical model, subgroup analysis, and interpretation
Results
Respondent characteristics: socio-demographic data
Sample characteristics (N = 211) | Percentage (%) |
N
|
---|---|---|
Gender | ||
Male | 64.5 | 136 |
Female | 35.5 | 75 |
Age groups (years) | ||
54 years and younger | 26.1 | 55 |
55–64 years | 46.0 | 97 |
65 years and older | 28.0 | 59 |
Mean | 58.9a
| |
Marital Status | ||
Married | 68.2 | 144 |
Widowed | 9.0 | 19 |
Divorced or separated | 10.4 | 22 |
Single | 4.3 | 9 |
In a relationship, but not married | 8.1 | 17 |
Education level | ||
No degree | 2.4 | 5 |
Junior/middle school certificate | 16.1 | 34 |
Intermediate high school certificate, secondary school certificate | 27.0 | 57 |
Vocational school/advanced technical certificate | 25.1 | 53 |
Abitur, high school diploma, in Germany: university entrance qualification | 14.1 | 31 |
Technical college degree | 7.6 | 16 |
University degree or higher | 7.1 | 15 |
Employment status | ||
Employed full-time | 3.3 | 7 |
Employed part-time | 8.5 | 18 |
Self-employed | 1.9 | 4 |
Homemaker/housewife | 11.8 | 25 |
Retired | 40.3 | 85 |
Disabled/unable to work | 32.7 | 69 |
Unemployed | 1.4 | 3 |
Time of NSCLC diagnosis | ||
Less than 6 months ago | 6.6 | 14 |
6 Months–1 year ago | 13.7 | 29 |
1–2 years ago | 36.0 | 29 |
2–5 years ago | 34.1 | 72 |
More than 5 years ago | 9.0 | 19 |
Not sure | 0.5 | 1 |
Treatment status-current treatmenta
| ||
No treatment, but regular monitoring/check-ups | 33.2 | 70 |
Surgery | 0.9 | 2 |
Radiotherapy | 20.4 | 43 |
Drug therapy (including chemotherapy) | 82.5 | 174 |
Other | 0.5 | 1 |
Treatment status-previous treatmenta
| ||
No treatment, but regular monitoring/check-ups | 8.1 | 17 |
Surgery | 64.9 | 137 |
Radiotherapy | 77.3 | 163 |
Drug therapy (including chemotherapy) | 84.8 | 179 |
Other | – | – |
With whom do you live in a household?a
| ||
Spouses | 77.3 | 163 |
One or more adult children (18 years or older) | 13.7 | 29 |
One or more minor children (under 18 years) | 8.5 | 18 |
Parents/parent | – | – |
I live alone | 19.9 | 42 |
Others | 1.4 | 3 |
Within your treatment how severe did the side effect diarrhea occur? | ||
Not at all | 12.3 | 26 |
Mild | 52.1 | 110 |
Moderate | 29.4 | 62 |
Severe | 5.2 | 11 |
Not sure | 0.9 | 2 |
Within your treatment how severe did the side effect fatique occur? | ||
Not at all | 8.5 | 18 |
Mild | 26.1 | 55 |
Moderate | 37.4 | 79 |
Severe | 19.4 | 41 |
Not sure | 8.5 | 18 |
Results of the main effects model
Attribute | Coeff. | Odds ratio | SE | 95 % confidence interval |
P value |
z
| |
---|---|---|---|---|---|---|---|
UBa
| LBb
| ||||||
Progression-free survival | 1.087 | 2.966 | 0.0525 | 1.1902 | 0.9846 | 0.000 | 20.73 |
Rash | 0.432 | 1.540 | 0.0396 | 0.5094 | 0.3541 | 0.000 | 10.89 |
Nausea and vomiting | 0.605 | 1.832 | 0.0481 | 0.6995 | 0.5109 | 0.000 | 12.58 |
Diarrhea | 0.427 | 1.533 | 0.0396 | 0.5051 | 0.3498 | 0.000 | 10.79 |
Fatigue (tiredness) | 0.423 | 1.527 | 0.0380 | 0.4977 | 0.3486 | 0.000 | 11.13 |
Tumor-associated symptoms | 1.090 | 2.975 | 0.0562 | 1.2005 | 0.9801 | 0.000 | 19.39 |
Mode of administration | 0.141 | 1.152 | 0.0311 | 0.2023 | 0.0804 | 0.000 | 4.55 |
Results of the latent class model and analysis of subgroups
Preference differences depending on structural variables
Preference patterns class 1
Evaluation of structural variables for class 1
Preference patterns class 2
Evaluation of structural variables for class 2
Preference patterns class 3
Evaluation of structural variables for class 3
Verification of model performance using a likelihood ratio test
Parameter (standard error) | |||
---|---|---|---|
Attribute | Class 1 coef. (SE) | Class 2 coef. (SE) | Class 3 coef. (SE) |
Progression-free survival | 4.032 (0.9151)*** | 3.608 (0.8595)*** | 0.611 (0.0805)*** |
Rash | 0.436 (0.1345)*** | 0.737 (0.1967)*** | 0.775 (0.0840)*** |
Nausea and vomiting | 0.883 (0.1995)*** | 1.603 (0.4336)*** | 0.854 (0.0866)*** |
Diarrhea | −0.781 (0.1776)*** | 1.585 (0.3491)*** | 0.668 (0.0701)*** |
Fatigue (tiredness) | 0.034 (0.3603)* | 1.305 (0.3144)*** | 0.514 (0.0709)*** |
Tumor-associated symptoms | 2.442 (0.4874)*** | 3.574 (0.6994)*** | 0.726 (0.0890)*** |
Mode of administration | −1.378 (0.5593)** | 0.912 (0.2594)*** | 0.142 (0.0556)**
|
Proportion of patients per class | 47 (22.6%) | 85 (40.5%) | 79 (36.9%) |
Constant per class | −0.4895 (0.2075) | 0.0915 (0.2208) | – |
Class-membership parameters | |||
No treatment, only checkups (previous treatment) | – | – | ++ |
Education: vocational school | ++ | ||
Household: one or more adult children (18 years or older) | – | ++ | |
Currently in treatment with radiotherapy | – | ++a
| |
Marital status: widowed and/or divorced | ++ | ||
High burden of side effects: diarrhea | ++ | ||
”Not sure” with side effect “fatigue” | ++ |
Discussion:
Interpretation of DCE results
Descriptive results
Relative importance
Subgroup effects
Marginal rate of substitution and time equivalent
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An increase of 0.359 from mild to severe side effects of skin (rash).
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An increase of 0.257 from mild to severe nausea and vomiting.
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An increase of 0.364 from mild to severe diarrhea.
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An increase of 0.367 from mild to severe tiredness/fatigue.
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An increase of 0.142 from mild to severe tumor related symptoms.
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2.782 months for an improvement in side effects of skin (rash).
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3.896 months for an improvement in nausea and vomiting.
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2.750 months for an improvement in diarrhea.
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2.724 months for an improvement in tiredness/fatigue.
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7.019 months for an improvement in tumor related symptoms.