Objective Versus Self-Reported Adherence to Airway Clearance Therapy in Cystic Fibrosis

Respir Care. 2019 Feb;64(2):176-181. doi: 10.4187/respcare.06436. Epub 2018 Dec 11.

Abstract

Background: Historically, studies of adherence to airway clearance therapy in cystic fibrosis (CF) have relied on self-reporting. We compared self-reported airway clearance therapy adherence to actual usage data from home high-frequency chest wall compressions (HFCWC) vests and identified factors associated with overestimation of adherence in self-reports.

Methods: Pediatric patients who perform airway clearance therapy with a HFCWC vest were eligible to participate. Objective adherence data were obtained from the HFCWC device, which records cumulative utilization time. Two readings at least 5 weeks apart were collected. Objective adherence was recorded as a ratio of mean-to-prescribed daily use (%). Self-reported adherence data were collected with a caregiver survey at enrollment. Adherence rates were categorized as low (< 35% of prescribed), moderate (36-79% of prescribed), and high (≥ 80% of prescribed). An overestimation was present when self-reported adherence was at least one category higher than objective adherence.

Results: In the final sample (N = 110), mean adherence by usage data was 61%. Only 35% of subjects (n = 38) were highly adherent, and 28% (n = 31) were low adherent. In contrast, 65% of subjects (n = 72) reported high adherence and only 8% (n = 9) reported low adherence (P < .001). Nearly half of self-reports (46%) overestimated adherence. In a multiple regression analysis, overestimation was associated with multiple airway clearance therapy locations (odds ratio 7.13, 95% CI 1.16-43.72, P = .034) and prescribed daily use ≥ 60 min (odds ratio 3.85, 95% CI 1.08-13.76, P < .038). Among subjects with prescribed daily airway clearance therapy ≥ 60 min, the odds of overestimating adherence increased 3-fold (odds ratio 3.04, 95% CI 1.17-7.87, P = .02) in a lower-income (< $50,000/y) environment.

Conclusions: Self-reports overestimated actual adherence to airway clearance therapy, and the overestimation increased with treatment occurring in multiple households and prescribed therapy duration. Among participants with prescribed airway clearance therapy ≥ 60 min, overestimation increased with lower income. Objective measures of adherence are needed, particularly for lower-income children and those receiving treatments in multiple locations.

Keywords: adherence; airway clearance; chest physical therapy; cystic fibrosis; high-frequency chest wall compressions.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Airway Management / instrumentation
  • Airway Management / psychology
  • Airway Management / statistics & numerical data*
  • Chest Wall Oscillation / instrumentation
  • Chest Wall Oscillation / statistics & numerical data*
  • Child
  • Cystic Fibrosis / psychology
  • Cystic Fibrosis / therapy*
  • Female
  • Humans
  • Male
  • Odds Ratio
  • Patient Compliance / psychology
  • Patient Compliance / statistics & numerical data*
  • Self Report / statistics & numerical data*
  • Time Factors