Determinants of objective adherence to nebulised medications among adults with cystic fibrosis

Abstract

Objectives: To understand the differences between high or low nebuliser adherers (i.e. used ≥80% or ≤40%, respectively, of all nebulised treatments over one year) among adults with cystic fibrosis (CF). Methods: Of 36 eligible adults with CF invited from a UK CF centre, 20 were recruited (10 high, 10 low adherers). Adherence was objectively measured using electronic data capture. Participants took part in a semi-structured interview and provided quantitative measures of habit, self-control, life chaos, perceived treatment burden, capability, motivation and opportunity. Quantitative measures 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. Habit strength 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 appear more likely to make nebuliser use habitual, and adapt more effectively to using nebulisers by creating and seizing opportunities for nebuliser use. Nebuliser adherence interventions might usefully target the development of routines for instigating nebuliser use, and identification of opportune moments for nebuliser use.