First author [ref.] | Year | Adherence definition/term | Assessment method | Details | Validity/reliability |
Tettersell [32] | 1993 | Taking inhalers as prescribed | Patient-reported, single item | One item: “do you take your inhalers as prescribed?”; four response options: “always”, “majority of the time (8 out of 10 doses)”, “about half of the time”, “only during or following an attack” | NR |
Bosley [33] | 1995 | Noncompliance; taking <70% of prescribed doses or omitting all doses for ≥1 week | Electronic monitoring | Turbuhaler Inhalation Computer; computed for two 6-week periods as (no. of doses taken)/(no. of doses prescribed)×100 | NR |
Apter [34] | 1998 | Use of ICS in the last 35 days | Electronic monitoring | MDIlog, last 35 of 42 days considered, computed for 12-h periods as (recorded − prescribed actuations)×100; mean truncated adherence computed per subject; dichotomised (<or>70%) | NR |
Bennett [35] | 1998 | Adherence to preventive ICS use | Patient-reported, published scale | RAAS [83] | α=0.75 |
Chambers [36] | 1999 | Frequency of ICS use | Patient-reported, single item | Item content not specified, four response options: “I use it at least twice a day almost every day”, “some days I use it at least twice, but on other days I don't use it at all”, I used to use it, but now I don't”, “I never used it”; dichotomised into “regular, twice daily” and “less than regular” | NR |
Schmaling [37] | 2000 | As-needed medication use | Canister weighting | Total number of medication inhalations for each day in the prescription period | NR |
Daily medication adherence | Canister weighting | Predicted use (no. days × no. puff per day) compared to actual use; computed as percent of prescribed medication used | NR | ||
Horne [38] | 2002 | Medication adherence | Patient-reported, published scale | MARS [38] | α=0.85 |
van Schayck [39] | 2002 | Medication compliance rate | Canister weighting | Medication used as a percentage of medication prescribed | NR |
Apter [40] | 2003 | Use of ICS in the last 42 days | Electronic monitoring | MDIlog, 42 days, computed for 12-h periods as (recorded − prescribed actuations)×100; mean truncated adherence computed per subject; divided into four categories (<20%, 20–<50%, 50–<75%, 75–100%) | NR |
Jessop [41] | 2003 | Adherence to preventative inhaled medication in the last 3 months | Patient-reported, published scale (adapted) | RAAS [83] and two extra items on accidental nonadherence | α=0.92 |
Labrecque [42] | 2003 | Conformity of SABA prescription use with accepted good use criteria | Medical (refill) records | Dichotomous, good use criteria: for SABA with no ICS use, the interval between the targeted SABA prescription and the following refill corresponds to a maximum daily use of two inhalations; for SABA with ICS use, the criterion above, and a daily ICS dose below a fixed threshold | NR |
Nishiyama [43] | 2003 | Reliever compliance | Patient-reported, interview | Patients were required to state the drugs and dosage regimens they used; their reports were compared with prescription information; three values were coded: “good”; “overused”; “underused” (first two also applied to reliever) | NR |
Preventer compliance | Patient-reported, interview | NR | |||
Balkrishnan [44] | 2005 | Adherence to controller pharmacotherapy | Medical (refill) records | Computed as: (days of prescription supply dispensed)/(days between prescription refills − number of days person was hospitalised); dichotomised as compliant (0.5–1.5) or not | NR |
Lacasse [45] | 2005 | Non-compliance | Electronic monitoring | MDIlog; calculated for 12 weeks daily as proportion of prescribed daily dose actually inhaled; dichotomised as compliant (>75%) or not | NR |
Stempel [46] | 2005 | Asthma medication refill rate | Medical (refill) records | Number of 1-month supply during the 12-month post-index period | NR |
Number of treatment days | Medical (refill) records | For monotherapy: total days supplied of medication For combination: total days supplied of ICS | NR | ||
SABA refill rates | Medical (refill) records | Number of 1-month supply during the 12-month post-index period | NR | ||
Bender [47] | 2006 | Adherence to ICS/LABA | Medical (refill) records | Total days supplied during follow-up period | NR |
Persistence | Medical (refill) records | Time to discontinuation computed as number of days from index date to date preceding the pre-specified gap when supply was exhausted | NR | ||
Chatkin [48] | 2006 | Compliance | Canister weighting | (Total quantity of medication used)/(quantity prescribed, i.e. three canisters in 3 months); dichotomised as compliant (>85%) or not | NR |
Hasegawa [49] | 2006 | Drug compliance | Medical (prescription and refill) records | Computed for 6 months as (number of medicines dispensed)/(number of medicines prescribed)×100; capped at 100% | NR |
Marceau [50] | 2006 | Persistence versus discontinuation: having prescriptions continuously renewed within the period | Medical (refill) records | Computed as the sum of three times the duration of the current prescription (in days) plus all overlaps accumulated since therapy start; discontinuation date was the end date of the last filled prescription plus all overlaps | NR |
Ohm [51] | 2006 | Use of ICS+LABA | Electronic monitoring | Advair diskhaler; computed as (number of counted doses)/(number of prescribed doses)×100; dichotomised as good adherence (≥80%) or not | NR |
Medication adherence | Patient-reported, published scale | MARS [38] | NR | ||
Tavasoli [52] | 2006 | Compliance to prescribed MDI drugs | Patient-reported, interview | Four items: "do you use your prescribed spray (MDI drug) regularly?", "have you ever had any history of not using your spray?", "do you still use your last prescribed spray?", "how do you use your spray? Show me"; response scales from 0 to 4 | NR |
Ulrik [53] | 2006 | Intentional nonadherence | Patient-reported, single item | One item: “how often do you decide not to take your controller medication?”; five response options: “almost every day”, “a couple of times every week”, “a couple of times every month”, “a couple of times every year”, “hardly ever” | NR |
Adherence | Patient-reported, single item | Item not specified; responses reported on a three-level scale: taking controller therapy as prescribed, less, or more than prescribed | NR | ||
Williams [54] | 2007 | ICS adherence | Medical (refill) records | (Cumulative days supplied)/ (total number of days between refills for 1-year study period); analyses performed also with adherence stratified (0%, 0%–80%, ≥80%) | NR |
Williams [55] | 2007 | Primary non-adherence | Medical (refill) records | No prescription fill information recorded for 3 months after index prescription | NR |
ICS adherence | Medical (refill) records | Computed as (total days supplied)/(number of days of observation)×100; adherence stratified (0%, 0–80%, ≥80%) | NR | ||
Breekveldt-Postma [56] | 2008 | Persistence during the first year | Medical (refill) records | Computed as number of days from start to time of first failure to continue renewal of initial prescription, based on (number of units dispensed)/(number of units to be used per day as defined in pharmacy) | NR |
Janson [57] | 2008 | ICS nonadherence during the last 14 days | Patient-report, interview | Nursing home assessment of ICS prescription and use, based on inspection of current asthma medication and two questions: “How many puffs and how many times per day did your doctor tell you to use this?”, “During the past 14 days, how many puffs and how many times per day have you used this?”; dichotomised as adherent (≥7 days of use in previous 14 days) or not | NR |
SABA or LABA overuse | Patient-reported, interview | Nursing home assessment on SABA and LABA prescription and use, dichotomised as overuse (average >8 puffs of SABA or >2 puffs of LABA -single or combination- per day) or adherent | NR | ||
Martínez-Moragón [58] | 2008 | Frequency of ICS use | Patient-reported, single item | One item, not specified, adapted after (37); four response options, from “never” to “at least twice a day almost every day”, dichotomised into “almost every day” versus “rarely if ever” | NR |
McGann [59] | 2008 | “How closely an individual's medication taking behaviours, as measured by the DOSER, approximated prescribed use instructions provided by the healthcare provider” | Electronic monitoring | DOSER; ratio of the number of observed correct prescribed use days between day 3 and 14 | Agreement with other measures (not specified) 84.32% |
Menckeberg [60] | 2008 | Medication acquisition | Medical (refill) records | (Total days supplied)/(total number of days from first and last refill date)×100 | |
Medication adherence | Patient-reported, published scale | MARS [38] | α=0.81 | ||
Wells [61] | 2008 | ICS adherence; the proportion of time that the patient had medication available during last 6 months | Medical (refill) records | (Total days supplied)/(number of days of observation)×100 | NR |
Axelsson [62] | 2009 | Medication adherence | Patient-reported, published scale | MARS [38] | α=0.71 |
Bae [63] | 2009 | Prescription refill adherence | Medical (refill) records | (Number of ICS refills)/12×100; categorised as appropriate use (>80%), underuse (50–80%), or extreme underuse (<50%) | NR |
Subjective self-reported adherence | Patient-reported, single item | One item: “how often did you take your ICS as prescribed for last 1 year?”; response on a visual analogue scale from 0% to 100%; categorised as appropriate use (>80%), underuse (50–80%), and extreme underuse (<50%) | NR | ||
Laforest [64] | 2009 | Intentional interruption | Patient-reported, single item | Six items included: 1) accidental interruption, 2) intentional interruption when feeling better, 3) intentional interruption when feeling worse, 4) reduced use when feeling better, 5) more frequent use of ICS in case of preliminary signs of asthma attack, and 6) intentional changes of doses independently of physician; analyses performed on intentional (when feeling better) and accidental interruption | NR |
Accidental interruption | Patient-reported, single item | ||||
Ponieman [65] | 2009 | Medication adherence | Patient-reported, published scale | MARS [38]; dichotomised as good adherence (≥4.5) or not | α=0.86 |
Friedman [66] | 2010 | Prescription fills | Medical (refill) records | Total number of prescription refills during the post-index period | NR |
Percentage of days covered | Medical (refill) records | (Number of days patients had medication on hand)/(total number of post-index days=365)×100 | NR | ||
Takemura [67] | 2010 | Self-reported adherence to inhalation regimen | Patient-reported, published scale (adapted) | Modification of RAAS [83] concerning the use of inhaled controller medications; mean adherence score computed; dichotomised as good adherence (≥4.0) or not | NR |
Bolman [68] | 2011 | Medication adherence | Patient-reported, published scale | MARS [38] | α=0.89 |
Emilsson [69] | 2011 | Medication adherence | Patient-reported, published scale | MARS [38] | α=0.77 |
Small [70] | 2011 | Physician-perceived compliance; “the extent to which the patients are perceived to follow their physician's prescribing instructions and advice” | Physician-reported, bespoke scale | Two items (not specified) on physician-perceived patients' compliance regarding frequency of use and inhaler use; five response options from “not at all compliant” to “fully compliant” | α=0.92 |
Suzuki [71] | 2011 | ICS adherence | Medical (prescription and refill) records | Ratio of doses dispensed in the pharmacy divided by prescribed doses documented in medical charts | NR |
Foster [72] | 2012 | Adherence with ICS/LABA | Electronic monitoring | Smart inhaler; daily adherence calculated as (no. recorded actuations/no puffs prescribed)×100, capped at 100% and averaged for the last 4 weeks of 2 months monitored | NR |
Patient-reported, published scale | Morisky adherence scale [84] | NR | |||
Patient-report, single item | Estimation of own inhaler use (days/week and puffs per day) in the last 4 weeks | NR | |||
Ahmedani [73] | 2013 | ICS adherence | Medical (prescription and refill) records | (Total days supplied)/(3-month observation period)×100 | NR |
Axelsson [74] | 2013 | Medication adherence | Patient-reported, published scale | MARS [38] | α=0.75 |
Price [75] | 2013 | ICS adherence | Patient-reported, published scale | MARS [38], categorised as “low”(“often” or “always” response to any question), “borderline” (´sometimeś responses to > 1 question), and “good” (any other answer) | NR |
Price [76] | 2013 | ICS adherence | Medical (prescription) records | (Total days supplied)/(365-day observation period)×100 | NR |
Schatz [77] | 2013 | Questionnaire low adherence | Patient-reported, published scale | Response to “how often are you actually taking your ICS medication now” compared to response to “based on your doctor's most recent instructions, how often were you advised to be taking your ICS medication now” (less frequently) | NR |
Percent of days covered | Medical (refill) records | Days’ supply of dispensed canisters over the follow-up at 3, 6, and 12 months | NR | ||
Wells [78] | 2013 | ICS adherence | Medical (prescription and refill) records | Continuous multiple-interval measure of medication availability equals number of days' supply for each fill/total number of days between the present and next fill; averaged for the observation period | NR |
Baddar [79] | 2014 | Compliance with controller treatment | Interview cross-checked with electronic patient records | Good equals taking 100% of daily prescribed medication and ≤2 missed doses/administrations per week; partial equals taking more or less than their daily prescribed medication; poor equals any other inhaler use patterns | NR |
Federman [80] | 2014 | ICS adherence | Dose count | Review of dose counters for all dry powder inhaler devices during the first 3 months and 30 days after each new prescription; dichotomised as <80% and ≥80% | NR |
Taylor [81] | 2014 | Adherence to ICS prescriptions | Medical (prescription) records | Prescription possession ratio: (number of days prescribed during calendar year)/(number of days in the interval)×100 | NR |
van Steenis [82] | 2014 | ICS adherence | Patient-reported, published scale (adapted) | Morisky adherence scale [84], adapted | NR |
ICS adherence | Medical (refill) records | Proportion of days covered: (number of days' supply)/(365 or truncated if medication gap ≥182)×100; dichotomised as <80% and ≥80% | NR |
NR: not reported; ICS: inhaled corticosteroids; RAAS: Revised Asthma Adherence Scale; MARS: Medication Adherence Rating Scale; MDI: metered-dose inhaler; SABA: short-acting β2-agonists; LABA: long-acting β2-agonists; α: Cronbach's α test.