Determinants of objective adherence to nebulised medications among adults with cystic fibrosis: an exploratory mixed methods study comparing low and high adherers

Abstract

Objectives: Adherence to nebulised treatment is typically low among people with cystic fibrosis (CF). This study sought to identify factors differentiating high or low nebuliser adherence patterns (i.e. ≥80% or <50% of all nebulised treatments over one year) among adults with CF. Design: A mixed methods cross-sectional exploratory comparison of low and high adherers to nebulised medications. Methods: Of 36 eligible adults invited from a UK CF centre, 20 were recruited (10 high, 10 low adherers). Adherence was objectively measured using electronic data capture. Participants completed a self-report questionnaire comprising measures of hypothesised predictors (habit, self-control, life chaos, perceived treatment burden, capability, motivation and opportunity), then took part in a semi-structured interview. Quantitative data were compared between groups, and interview data were thematically analysed. Results: High adherers reported stronger habit and greater opportunities, though habit and perceived opportunity scores were highly positively correlated. No other quantitative measure distinguished between groups. Habitual instigation tendency attenuated the relationship between treatment complexity and perceived treatment burden. Indeed, in interviews, high adherers reported that routinisation and greater automaticity made treatment burden more manageable. Conclusions: High adherers seized more opportunities for nebuliser use, adapted their lives more effectively to using nebulisers and were more likely to make nebuliser use habitual. Nebuliser adherence interventions among adults with CF might usefully target development of routines for instigating nebuliser use, and identification of opportune moments for nebuliser use

Role of habit in treatment adherence among adults with cystic fibrosis

“…Adherence data were downloaded from chipped nebulisers (eTrack) in the 3-month period following the point of recruitment, and calculated as ‘normative adherence’,8 a measure that takes into account a person’s characteristics when defining the minimum required treatment regimen (see online supplementary appendix). Participants were divided into three adherence categories (<50% for low adherence, 50%–79.9% for moderate adherence, ≥80% for high adherence) to mirror the analysis of our earlier Sheffield study 6. These adherence categories were used in various other CF-related studies and were chosen based on the relationship with health outcomes 1 9…”

“…Our earlier exploratory mixed-methods study in Sheffield showed that high adherers had stronger habit than did low adherers 6. High adherers also described automatically ‘remembering’ to use their nebulisers; for example, one participant experienced the urge to use his nebuliser after walking his dog every morning 6.…”

“…High adherers also described automatically ‘remembering’ to use their nebulisers; for example, one participant experienced the urge to use his nebuliser after walking his dog every morning 6. To determine whether the habit–adherence association exists in other cohorts of adults with CF, we performed a secondary analysis using data prospectively collected during a pilot randomised controlled trial (RCT) (ACtiF pilot, ISRCTN13076797).…”

A matter of habit: Recognizing the multiple roles of habit in health behaviour

“…In some circumstances, forming habit for a key preparatory behaviour may have greater impact than automating the target behaviour itself (Kaushal et al, 2018). Interventions that seek to increase performance frequency via direct manipulation of the target behaviour should promote habitual instigation, which appears to be the habit mechanism responsible for behaviour maintenance (Hoo et al, 2017). Targeting habitual instigation at population level is however likely to be difficult.…”

“…Using SRHI variants worded to specify instigation or execution for three discrete health behaviours, Gardner et al (2016) showed that habitual instigation predicted behaviour frequency but execution did not (see too . A study of people with cystic fibrosis showed that a measure of habitual instigation of nebulizer use discriminated between adherers to the nebulizer regimen and non-adherers, but a measure of habitual execution of nebulizer use did not (Hoo, Boote, Wildman, Campbell, & Gardner, 2017).…”