Study characteristics of empirical studies on inhaled medication adherence in adults with asthma
| First author [ref.] | Country | Year | Objectives | Study design | Data sources | Sample size n | Age years | Females | Asthma severity: FEV1 % | Inhaled medication |
| Tettersell [32] | UK | 1993 | Relationship between knowledge and treatment adherence | Cross-sectional (ASD) | Primary care | 100 | 50.1±20.6 | 9% | Moderate to severe | NR |
| Bosley [33] | UK | 1995 | Psychological factors related to asthma self-reported care and compliance | Prospective (DPA) | Primary care and outpatient clinic | 72 | 45±15 | n=62 | NR | ICS+LABA, ICS/LABA |
| Apter [34] | USA | 1998 | Patient characteristics related to adherence to twice daily ICS treatment | Prospective (DPA and ASD) | Outpatient clinics | 50 | 46±14 | n=37 (74%) | 75±21 | ICS |
| Bennett [35] | UK | 1998 | Associations between protection motivation theory factors (health threat, outcome, self-reported efficacy) and adherence to preventive ICS use | Cross-sectional (ASD) | Primary care | 71 | 47±19.25 | n=40 | NR | ICS |
| Chambers [36] | USA | 1999 | Factors associated with regular ICS use | Cross-sectional (ASD) | Primary care | 394 | Median: 36 | 75% | NR | ICS |
| Schmaling [37] | USA | 2000 | Development of measures to assess psychological factors important to adherence with medication regimens | Cross-sectional (ASD) | Private asthma clinic and hospital | 53 | 36.1±9.6 | 62.3% | NR | ICS, LABA, SABA |
| Horne [38] | UK | 2002 | Relationship between reported adherence to preventer medication and perceptions and asthma medication | Cross-sectional (ASD) | Primary care | 100 | 49.3±18.1 | 61% | NR | NR |
| Van Schayck [39] | Netherlands | 2002 | Influence of inhalation device, patients' inhaler perceptions, daily frequency, and duration of treatment on medication compliance | Prospective (DPA and ASD) | Primary care | 34 | 37±13 | n=19 | NR | LABA or SABA |
| Apter [40] | USA | 2003 | Barriers to adherence as explanations of racial-ethnic differences in adherence | Prospective (DPA and ASD) | Primary and secondary care | 85 | 47±15 | n=61 (72%) | 65±19 | ICS |
| Jessop [41] | UK | 2003 | Relationship between cognitive and emotional representations of asthma and adherence to inhaled preventative asthma medication | Cross-sectional (ASD) | Primary care | 330 | 57.2±17.9 | n=204 (61.8%) | NR | NR |
| Labrecque [42] | Canada | 2003 | Assess compliance to asthma guidelines and influence of age on SABA utilisation | Retrospective (ASD) | Health insurance database claims | 987 | Range: 5–45 | NR | Severe asthma excluded | SABA (with or without ICS) |
| Nishiyama [43] | UK | 2003 | Determine if the Jones Morbidity Index can be used in community pharmacy to identify those who have poor control | Cross-sectional (ASD) | Pharmacy database | 306 | 38.5±20.6 | 54.5% | NR | ICS and SABA |
| Balkrishnan [44] | USA | 2005 | Asthma-related healthcare costs, medication adherence, ICS and newly started on MON versus SAL | Retrospective (DPA) | Health insurance database claims | 198 | 22±19.5 MON 24±18.2 SAL | 52.5% MON 59.8% SAL | NR | ICS+LABA versus ICS+MON |
| Lacasse [45] | Canada | 2005 | Describe patterns of compliance and identify factors determining the compliance to ICS in adults | Prospective (DPA and ASD) | NR | 124 | 47±15 | n=73 | Mild–moderate | ICS |
| Stempel [46] | USA | 2005 | Patient adherence with several medication regimens: FP/SAL, FP+SAL, FP+MON, FP, MON | Retrospective (ASD) | Health insurance database claims | 3503 | 38.7±17 | 64.5% | NR | ICS, LABA, MON |
| Bender [47] | USA | 2006 | Factors related to refill adherence to FP/SAL | Retrospective (ASD) | Pharmacy database | 5504 | 54±22 | 60.2% | NR | ICS/LABA |
| Chatkin [48] | Brazil | 2006 | Rate of compliance with preventive treatment for moderate and severe persistent asthma | Prospective (DPA) | Primary care | 131 | 44.4±16.6 | 71% | Severe persistent | ICS/LABA |
| Hasegawa [49] | Japan | 2006 | Comparison between compliance to FP diskus versus FP diskhaler | Retrospective (ASD) | Pharmacy database | 337 | 54.2±16.8 FP diskhaler 57.7±18.2 FP diskus | 56.3% FP diskhaler 57% FP diskus | NR | ICS |
| Marceau [50] | Canada | 2006 | Compare persistence, adherence and effectiveness between patients with asthma starting combination or concurrent therapies (ICS and LABA) | Prospective (DPA and ASD) | Health insurance database claims | 5118 | 32.6±8.2 | 63.3% | NR | ICS/LABA versus ICS+LABA |
| Ohm [51] | USA | 2006 | Explore asthma symptom perception and its relationship with adherence to asthma treatment | Cross-sectional (ASD) | Asthma/allergy clinics | 120 | 44.8±9.27 | 78% | Mild to severe | ICS |
| Tavasoli [52] | Ireland | 2006 | Factors related to patients' compliance with prescribed metered dose inhaler drugs | Cross-sectional (ASD) | Outpatient department | 160 | 47.67±12.78 | n=105 (65.6%) | NR | ICS, LABA, SABA |
| Ulrik [53] | Denmark | 2006 | Patient-related aspects of adherence among adult asthmatics | Cross-sectional (ASD) | Community (web-based panel for market research) | 509 | Range: 18–45 | n=317 (62%) | Mild: 77% Moderate: 12% Severe: 11% | ICS, ICS+LABA |
| Williams [54] | USA | 2007 | Factors associated with ICS adherence among patients with asthma, and among African–American and white patients separately | Retrospective (ASD) | Health maintenance organisation | 176 | 40.8±7.7 | n=115 (68.1%) | NR | ICS |
| Williams [55] | USA | 2007 | Estimate rates of primary nonadherence and explore associated factors | Retrospective (ASD) | Health maintenance organisation | 1064 | 31.9±16.5 | 59.8% | NR | ICS |
| Breekveldt-Postma [56] | Netherlands | 2008 | Determinants of persistence with ICS | Prospective (DPA) | Pharmacy database | 5563 | Range: 0–34 | 51.5–57.2% | NR | ICS, ICS+LABA |
| Janson [57] | USA | 2008 | Describe asthma medication adherence, identify predictors of ICS underuse and SABA or LABA overuse | Cross-sectional (DPA and ASD) | Primary and secondary care (random-digit dialling) | 158 | 48.7±7.4 ICS adherent, 46.7±8.5 ICS non-adherent, 46.5±8.8 SABA adherent, 46.2±7.3 SABA over use | 68% | NR | ICS and SABA or LABA |
| Martínez-Moragón [58] | Spain | 2008 | Relationship between failure to perceive dyspnoea associated with bronchial obstruction and treatment nonadherence in asthmatic patients | Cross-sectional (ASD) | Outpatient respiratory clinics | 48 | 45: range 30–60 | 50% | Moderate | ICS/LABA |
| McGann [59] | USA | 2008 | Relationship between denial of illness and compliance with inhaled controller asthma medications | Prospective (DPA) | Asthma clinics, advertisements, local college | 51 | 42±14.99; range: 18–68 | 82.3% | NR | NR (controller) |
| Menckeberg [60] | Netherlands | 2008 | Relationship between beliefs about ICS (necessity and concerns) and adherence | Cross-sectional/ retrospective (ASD) | Pharmacy database | 238 | 36.2±6.3 | 67% | NR | ICS |
| Wells [61] | USA | 2008 | Factors that contribute to ICS adherence among African–American and white adults with asthma | Retrospective (ASD) | Health maintenance organisation | 1006 | 43.1±10.4 | n=716 (71.2%) | NR | ICS |
| Axelsson [62] | Sweden | 2009 | Personality traits related to asthma control, health-related quality of life and adherence to regular asthma medication | Cross-sectional (ASD) | Epidemiological study | 109 | Range: 21–23 | 61.6% | NR | ICS/LABA, ICS, LABA, SABA |
| Bae [63] | South Korea | 2009 | Baseline information about ICS adherence in Korea, factors related to ICS adherence, clinical implications of ICS adherence for asthma control | Cross-sectional/ retrospective (ASD) | Clinical centres in university hospitals | 185 | NR | NR | NR | ICS or ICS/LABA |
| Laforest [64] | France | 2009 | Characteristics of patients with interruptions of ICS, intentional or accidental | Cross-sectional (ASD) | Primary care database | 204 | 53.8±19.6 | 59.3% | All ranges | ICS only or in combination |
| Ponieman [65] | USA | 2009 | Impact of potentially modifiable medication beliefs on adherence with ICS therapy across time | Prospective (DPA and ASD) | General internal medicine clinics | 261 | 48±13; range 20–87 | 82% | Persistent asthma | ICS |
| Friedman [66] | USA | 2010 | Adherence and asthma control in adolescents and young adults with mild asthma who began treatment with MF or FP | Retrospective (ASD) | Health insurance claims database | 1384 | Mean: 16.3 MF; 16.5 FP; range: 12–25 | 51.3% MF 55.3% FP | Mild | ICS |
| Takemura [67] | Japan | 2010 | Assess factors and mechanisms that contribute to and clinical outcomes relating to adherence | Cross-sectional (ASD) | Respiratory clinic | 176 | 57±15 | n=89 | NR | ICS, ICS/LABA |
| Bolman [68] | Netherlands | 2011 | Explain ICS adherence by the attitude, social influence and self-efficacy model and habit strength (moderation and mediation relationships) | Cross-sectional (ASD) | Pharmacy | 139 | 31.5±5.6 | n=98 (70.5%) | NR | ICS |
| Emilsson [69] | Sweden | 2011 | Influence of personality traits and beliefs about medicines on asthma medication adherence | Cross-sectional (ASD) | NR | 35 | 52.8±14.7 | n=25 | NR | ICS/LABA, ICS+LABA, ICS, LABA |
| Small [70] | UK | 2011 | Relationship between inhaler satisfaction and patient compliance Influence on health and patient-reported outcomes | Cross-sectional (ASD) | Specialists' and primary care | 2135 | NR in adults | NR | NR | NR |
| Suzuki [71] | Japan | 2011 | Associations between several factors of asthma therapy (patients adherence, asthma severity) | Retrospective (ASD) | University hospital | 50 | 36.3±7.9 | 46% | NR | ICS |
| Foster [72] | Australia | 2012 | Identify potentially modifiable beliefs and behaviours that predict ICS/LABA adherence | Prospective (ASD) | Community pharmacies, advertising, primary care, volunteer database | 99 | 47.6±15.8 | n=57 | 83%±23% | ICS/LABA |
| Ahmedani [73] | USA | 2013 | Relationships between locus of control factors (God, doctors, other people, change and internal) and ICS adherence | Cross-sectional (ASD) | Primary care | 1025 | 37.6±14.8 | n=675 (65.9%) | NR | ICS |
| Axelsson [74] | Sweden | 2013 | To determine the mediating effects of medication beliefs between personality traits and adherence | Cross-sectional (ASD) | Community | 516 | 47.4±15.6 | 60% | NR | ICS/LABA, ICS, LABA, SABA |
| Price [75] | UK | 2013 | Identify characteristics of patients who prefer once-daily controller regimen | Retrospective (ASD) | Primary care database | 3731 | 45.6±15; range: 2–94 | n=2174 (58.3%) | NR | ICS, ICS+LABA |
| Price [76] | UK | 2013 | Compare real life effectiveness of extra-fine and larger particle beclometasone | Case–control (DPA) | Primary care databases | 30354 | Range: 12–80 | n=17 808 (58.7%) | NR | ICS |
| Schatz [77] | USA | 2013 | Develop a questionnaire that reflects nonadherence risk and identifies adherence barriers | Prospective (DPA and ASD) | Health maintenance organisation | 420 | 41.6±9.1 | n=280 (66.7%) | NR | ICS, SABA |
| Wells [78] | USA | 2013 | Determine whether once daily dosing is associated with higher ICS adherence at least twice daily | Retrospective (DPA) | Health maintenance organisation | 1302 | 28.2±15.8 once daily 31.6±16.0 ≥twice daily | n=113 (51.1%) once daily n=656 (60.7%) ≥ twice daily | Low to severe | ICS |
| Baddar [79] | Oman | 2014 | Relationships between patient compliance, inhaler technique and asthma control level | Cross-sectional (ASD) | University hospital | 218 | Range: 12–72 | 65.1% | NR | ICS, ICS/LABA, ICS+LABA |
| Federman [80] | USA | 2014 | Associations of self-management behaviours (e.g. medication adherence and inhaler technique) with health literacy | Prospective (DPA) | Outpatient clinics | 433 | Mean: 67; 45% aged 60–64, 39% aged 65–74, 16% aged ≥75 | 83.8% | Moderate or severe | ICS only or in combination |
| Taylor [81] | UK | 2014 | To develop an annual measure of ICS adherence from prescribing data and statistically model ICS adherence controlling for patient factors | Retrospective (DPA) | Primary care database | 292738 | 38.7± 15.4 | NR | BTS/SIGN step 2–5 | ICS |
| Van Steenis [82] | Netherlands | 2014 | Relationship between ICS necessity and concerns, beliefs and subjectively and objectively measured adherence and the agreement between these measures | Cross-sectional (ASD) | Pharmacy | 93 | 43.7±14.5; range: 18–77 | n=55 (59.1%) | NR | ICS only or in combination |
Data are presented as mean±sd, unless otherwise stated. FEV1: forced expiratory volume in 1 s; ASD: adherence simultaneous with determinants measurement; NR: not reported; DPA: determinants preceding adherence measurement; ICS: inhaled corticosteroids; LABA: long-acting β2-agonists; SABA: short-acting β2-agonists; MON: montelukast; SAL: salmeterol; FP: fluticasone proprionate; MF: mometasone furoate; BTS: British Thoracic Society; SIGN: Scottish Intercollegiate Guidelines Network.