Purpose
To identify actionable risk factors for medication non-adherence.
Acronym
ASK-20
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Adherence Starts with Knowledge 20
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Populations
Key Descriptions
- Patient self report survey of medication adherence barriers
- 20 clinically actionable items representing multiple factors that affect medication adherence
- Each item has 5 response options
- Items 1-15 are rated from strongly agree to strongly disagree
- Items 16-20 are rated from in the last week to never
- Total score is the sum of each response ranging from 20-100 with higher scores suggesting greater barriers to adherence
- Total Barrier Count (TBC) score yields the number of barriers identified on a scale of 0-20 where 0 indicates no barriers and 20 indicates the maximum number of barriers
Number of Items
20
Time to Administer
5 minutes
Or less
Required Training
Reading an Article/ManualAge Ranges
Adult
18 - 64
yearsElderly Adult
65 +
yearsInstrument Reviewers
Initially reviewed by Lynne A. Marino OTR/L and Karen E. Majeski OTR/L December, 2016; Reviewed and revised by Edeth Engel October 2017.
ICF Domain
ActivityParticipation
Measurement Domain
Activities of Daily LivingGeneral Health
Considerations
The ASK-20 survey may prove to be a useful tool to
• Identify risk factors for medication non-adherence
• Facilitate discussion of adherence problems between healthcare providers and clients
• Provide barrier-specific interventions to improve medication adherence
The ASK-20 discriminates among different levels of patient reported medication adherence and medication satisfaction.
The ASK-20 correlates with generic measures of health related quality of life and disease specific patient self-report measures.
Floor effects were achieved in two studies (Matza et al, 2008; Atsuta et al, 2016). Four of the same questions achieved floor effects in both studies.
The TBC yielded below standard internal consistency in two studies (Matza et al, 2008; Park et al, 2016).
Due to floor effects and below standard internal consistency the ASK-20 may not accurately capture performance in research studies, although validity and reliability are adequate for clinical decision-making.
Portion of days covered (PDC) is an objective measure of the availability of medication. Low correlation with this measure is not problematic (Matza et al, 2008).
The ASK-12 survey was derived and validated in one small sized study in order to create a shorter version of the ASK-20. The initial study showed promising results but due to the small sample size it should be further studied for its validity and reliability (Matza et al, 2009).
Mixed Populations
back to PopulationsNormative Data
Asthma, Diabetes, Depression: (Hahn et al, 2008; n = 605 (200 with asthma, 202 with depression, and 203 with diabetes); mean age 52.5 +- 13.5)
-
Mean ASK-20 score in the study population was 43.3 (SD = 11)
-
Mean +/- SD TBC score in the study population was 4.2 (+/- 3.4)
Asthma, Diabetes, Congestive heart failure: (Matza et al, 2008; n = 112 (41 with asthma, 67 with diabetes, 1 with chf, 2 with diabetes and chf, 1 with diabetes and asthma); mean age 46.7 (10.6) years)
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Mean ASK-20 score in the study population 43.8 (range 0-100)
-
Mean TBC score in the study population 4.6 (range 0-14)
Test/Retest Reliability
Asthma, Diabetes, Congestive Heart Failure: (Matza et al, 2008)
-
Excellent test-retest reliability ASK-20: (ICC = .80)
-
Adequate test-retest reliability TBC: (ICC =.73)
Internal Consistency
Asthma, Diabetes, Depression: (Hahn et al, 2008)
-
Adequate internal consistency for the Total Barrier Count: (Cronbach’s Alpha = .77)
-
Excellent internal consistency for the ASK-20: (Cronbach’s Alpha = .85)
Asthma, Diabetes, Congestive Heart Failure: (Matza et al, 2008)
-
Adequate internal consistency for the ASK-20: (Cronbach’s Alpha = .76)
-
Poor internal consistency for TBC: (Cronbach’s Alpha = .67)
Criterion Validity (Predictive/Concurrent)
Concurrent Validity
Asthma, Diabetes, Congestive Heart Failure: (Matza et al, 2008)
|
Self-Report Measures |
ASK Score |
TBC Score |
|
|
Spearman Correlation |
Spearman Correlation |
|
Proportion of days covered (PDC) |
Poor r = -.13 |
Poor r = -.10 |
|
Morisky Medication Adherence Scale |
Excellent r = -.61 |
Adequate r = -.54 |
|
Appraisal of Diabetes Scale (ADS) |
Adequate r = .46 |
Adequate r = .39 |
|
Mini Asthma Quality of Life Questionnaire |
Adequate r = -.32 |
Adequate r = -.37 |
|
SF-12 physical component summary |
Poor r = -.19 |
Poor r = -.19 |
|
SF-12 mental component summary |
Adequate r = -.40 |
Adequate r = -.32 |
|
Self-reported non-adherence |
Adequate r = .49 |
Adequate r = .48 |
Criterion Validity
Asthma, Diabetes, Depression: (Matza et al, 2008)
|
|
|
ASK Score |
TBC Score |
|
Missed a dose of medicines in the past week: |
Yes
|
50.7 (+/-9.5) |
6.6 (+/-3.3) |
|
Missed a dose of medicines in the past week: |
No
|
38.8 (+/-9.1) |
2.8 (+/- 2.7) |
|
|
ASK |
TBC |
|
|
Pearsons r |
Pearsons r |
|
No. medicines taken a day |
Poor r = .03 |
Poor r =.11 |
|
No. times a day meds taken |
Poor r = -.01 |
Poor r =.06 |
|
No. days took less med than directed (past two weeks) |
Adequate r =.43 |
Adequate r= .43 |
|
No. days missed all doses of meds (past two weeks) |
Poor r =.30 |
Adequate r =.32 |
|
No. days took more med than directed (past two weeks) |
Poor r =.19 |
Poor r =.20 |
|
No. days took med at different times than directed (past two weeks) |
Adequate r =.36 |
Adequate r =.40 |
|
No. days did not take med exactly as directed (past two weeks) |
Adequate r =.46 |
Adequate r =.46 |
|
How much of the time do you take your meds exactly as directed? |
Excellent r =.60 |
Adequate r =.56 |
|
Overall, how satisfied are you with your current medicines? |
Adequate r =.56 |
Adequate r =.55 |
Content Validity
Development of the ASK-20 adherence barrier survey: (Hahn et al, 2008):
-
Items were identified based on a comprehensive literature review of medication adherence
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Items were reviewed by an advisory board of 18 physicians and nurse professionals (generalists, respiratory medicine, metabolic disease, neurology, and cardiology)
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Sensitivity, specificity and effect size was calculated for all items to determination of assessment structure, item reduction and content validity
Floor/Ceiling Effects
Asthma, Diabetes, Congestive heart failure: (Matza et al, 2008)
- Poor floor effects on 6 items (50%)
Pulmonary Diseases
back to PopulationsNormative Data
Asthma with long term Treatment of inhaled corticosteroid (ICS) or long acting beta-agonist use: (Atsuta et al, 2016; Japanese adults; n = 290 with a ICS subgroup n=111; mean age total population 57.7 (16.16); mean age for ICS subgroup 56.3 (13.92))
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Mean ASK-20 score for ICS subgroup 38.9
-
Mean TBC score for ICS subgroup 3.5
Internal Consistency
Asthma with long term inhaled corticosteroids: (Atsuta et al, 2016)
-
Adequate internal consistency for the ASK-20 for the total population: (Cronbach’s Alpha = .76)
-
Poor internal consistency for TBC for the total population: (Cronbach’s Alpha = .65)
Construct Validity
Discriminant Validity:
Asthma with long term inhaled corticosteroids: (Atsuta et al, 2016)
-
Adequate correlation between percentage of ICS adherence rates and the mean ASK-20 total score for ICS subgroup (r = -0.51)
-
Adequate correlation between percentage of ICS adherence rates and the mean total barrier count for ICS subgroup (TBC) (r = -0.58)
Floor/Ceiling Effects
Asthma with long term Treatment of inhaled corticosteroid (ICS) or long acting beta-agonist use: (Atsuta et al, 2016)
-
Poor floor effects in 9 items (50% of total study population)
Bibliography
Hahn, S.R., Park, J., Skinner, E.P., Yu-Isenberg, K.S., Weaver, M.B., Crawford, B., Flowers, P.W. Development of the ASK-20 adherence barrier survey (2008) Current Medical Research and Opinion, 24 (7), pp. 2127-2138. doi: 10.1185/03007990802174769
Matza, L.S., Park, J., Coyne, K.S., Skinner, E.P., Malley, K.G., Wolever, R.Q. Derivation and validation of the ASK-12 adherence barrier survey (2009) Annals of Pharmacotherapy, 43 (10), pp. 1621-1630. doi: 10.1345/aph.1M174
Matza, L.S., Yu-Isenberg, K.S., Coyne, K.S., Park, J., Wakefield, J., Skinner, E.P., Wolever, R.Q. Further testing of the reliability and validity of the ASK-20 adherence barrier questionnaire in a medical center outpatient population (2008) Current Medical Research and Opinion, 24 (11), pp. 3197-3206. doi: 10.1185/03007990802463642
Park, J., Jackson, J., Skinner, E., Ranghell, K., Saiers, J., Cherney, B. Impact of an adherence intervention program on medication adherence barriers, asthma control, and productivitydaily activities in patients with asthma (2010) Journal of Asthma, 47 (10), pp. 1072-1077. Cited 12 times. doi: 10.3109/02770903.2010.485660