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. 2019 Mar 12;12:101–127. doi: 10.2147/MDER.S198943

Table 6.

Study details and results from all identified studies of Propeller (adherence, clinical outcomes, and health care resources use)

Study name Study objective Study design Indication Sample size Follow-up period Key results
Barrett et al (2018)63 To evaluate the extent to which digital health intervention improves asthma outcomes in a real-world setting Prospective, single-arm Asthma 497 12 months • Patient mean age was 38 years (range 4–90 years) and 80% were adults
• At 12 months of follow-up, there was a 78% reduction in SABA use, an 84% reduction in night-time SABA use, and a 48% improvement in symptom-free days from baseline to month 12 (P<0.0001)
• The number of symptom-free days increased from 62% (first week) to 83% (2 months), to 88% (6 months), and to 90% (12 months) (P<0.0001)
Carl et al (2018)64 To determine whether a quality improvement program employing a digital health platform could improve pediatric asthma outcomes Prospective, single-arm Asthma 82 12 months • Patient age varied from 4 to 18 years
• Aggregate average controller adherence at 1, 2, 3, and 6 months post-enrollment timepoints demonstrated rates of 58%, 64%, 62%, and 55%, respectively
• Average weekly rescue event rate at these time points demonstrated decreased events from baseline (0.597/week) to 0.21 (63%), 0.20 (69%), 0.25 (59%), and (75%), respectively
Chen et al (2017)62 To assess the feasibility and clinical impact of a digital health intervention in a Medicare population with COPD or asthma Prospective, single-arm Asthma or COPD 236 (198 COPD, 38 asthma) 6 months • Among asthma patients:
• 65% of patients were 60 years or older
• At 6 months, SABA use decreased from 1.15 (first week) to 0.56 uses/person/day (last week); significant decrease of 51.4% (P<0.05)
• Increase in symptom-free days was 28% (46% at first week to 59% at last week)
• Among COPD patients:
• 78% of patients were 60 years or older
• At 6 months, SABA use decreased from 1.53 (first week) to 0.74 uses/person/day (last week); significant decrease of 51.7% (P<0.01)
Hoch et al (2017)65 To evaluate the feasibility of Propeller Health monitoring device, along with clinical outcomes Prospective, single-arm Asthma 25 3 months • Patient age varied from 6 to 17 years
• Average weekly adherence ranged from 76% (week 1) to 36% (week 12). The overall average weekly adherence for the cohort was 56% (SD 12%)
• Significant decrease in the rate of rescue medication; 76% (week 1) of study vs 40% (week 12) (P=0.012)
• Average weekly number of rescue medications declined from 9.9±14 (week 1) to 2.4±5.2 (week 12)
• There was no difference in the rate of night-time events between week 1 and week 12 of the study (P=0.727)
• Average number of asthma-free days increased from 4.8 days (±2.2) to 6 days (±1.6)
• FEV1 and FVC increased during the study period; however, the difference did not reach significance. FEF25–75 increased from an average of 80% predicted to 84% predicted (P=0.02)
Kenyon et al (2018)66 To assess the feasibility of a mobile health, ICS adherence reminder intervention and to characterize adherence trajectories immediately following severe asthma exacerbation in high-risk urban children with persistent asthma RCT Asthma 41 30 days • Patient age (mean ± SD) was 5.9±2.1 years
• Electronic monitoring of ICS use and adherence reminders delivered via text message were feasible for most participants, but there was no signal of effect
• After adjusting for age and parental education, mean adherence rates were 36% for the intervention group and 32% for the control group (P=0.73)
• Age had no significant impact on adherence rate. After adjusting for impact of intervention and education level, ICS adherence rates in <5 years old were 6% (95% CI 7, 44) compared with 43% (95% CI 30, 55) in those aged ≥5 years (P=0.14)
• Mean daily medication adherence trends over the 30-day intervention interval were also similar between the two groups, with broadly overlapping SDs
• Mean change in parent-reported portion of the cACT score over the 30 days of the intervention was not statistically significantly different between controls (3.1) and intervention (1.2) (P=0.16)
Merchant et al (2016)55 To measure real-world effectiveness of Propeller Health Asthma Platform to reduce use of SABA and improve asthma control RCT Asthma 495 12 months • Patient mean age was 36.6 years in the intervention group and 36.0 years in the routine care group. Approximately 30% of patients in both the groups were between 5 and 17 years of age.
• Daily mean number of SABA uses/person decreased by 0.41 for intervention group and by 0.31 for routine care between first week and remainder of the study (P<0.001)
• Proportion of SABA-free days increased 21% (intervention) and 17% (control) (P<0.01)
• ACT scores were not significantly different between arms; initially uncontrolled adults:
• Significantly larger improvement in ACT scores in the intervention group vs routine care (+6.2 and +4.6, respectively, P<0.01)
• Significantly larger improvement in the proportion with controlled asthma in intervention group vs routine care (63% controlled in the study period vs 49%, respectively; P<0.05)
Merchant et al (2017)68 To assess the impact of digital health intervention, which leveraged sensors and app-based education, on ER visits, hospitalizations, inpatient days, and clinic visits Retrospective, cohort Asthma 507 Data collected between July 2011 and September 2016 • Patient age was not reported
• Significant reductions in hospitalizations (2.7 to 0.6 days; 79% reduction; P<0.0001), inpatient days (7.9 to 1.4 days; 82% reduction; P<0.001) and ER visits (19.2 to 8.3 days; 57% reduction; P<0.0001)
• Non-acute asthma-related clinic visits increased (197–277 days; 41% increase; P<0.0001)
Su et al (2016)67 To identify hotspots of asthma symptoms; evaluate associations between asthma symptoms and environmental covariates in real-time and space Prospective, single-arm Asthma 140 20 months • Patient age was not reported
• By targeting environmental interventions that could have the largest impact on asthma within specific neighborhoods, 914,000 inhaler uses and $1.8 million of hospitalization costs could be avoided
Van Sickle et al (2010)58 To investigate if online feedback about remotely monitored inhaled bronchodilators improves composite measures of asthma control Prospective, single-arm Asthma 27 NR • Patient mean age was 35.5 years (range: 19–74 years)
• Asthma control scores increased significantly after receiving email reports after first (P=0.01) and second month (P=0.007)
• Patients reported more awareness of symptom frequency, level of control, asthma triggers, and increased adherence to preventive medication
Van Sickle et al (2011)59 To investigate if weekly feedback summarizing use of remotely monitored rescue medication improves asthma control Prospective, single-arm Asthma 34 4 months • Patient mean age was 41.8 years (range: 20–82 years)
• Mean ACT scores increased from 17.5 at entry to 19.5 at exit (P=0.01)
• Days with asthma symptoms in preceding 2 weeks declined from 6 at entry to 2.8 at exit (P=0.001)
• Nights with asthma symptoms in preceding 2 weeks declined from 2.7 at entry to 1.3 at exit (P=0.08)
• The ACT scores of 64% participants improved, 11% had no change and 23% worsened
Van Sickle et al (2013)60 To assess whether weekly email reports on monitored use of inhaled, short-acting bronchodilators improves composite asthma control measures Prospective, single-arm Asthma 30 4 months • Patient mean age was 36.8 years (range: 19–74 years)
• No significant difference in ACT scores between entry and first month values (P=0.66)
• ACT scores increased by 1.40 points (95% CI 0.61, 2.18) for each subsequent study month after patients received feedback
Van Sickle et al (2014)61 To determine the effect of sensor-enabled, mobile health asthma program on individual-level asthma outcomes, including frequency of asthma rescue medication use, asthma-free days and control status Prospective, single-arm Asthma NR 12 months • Patient age was not reported
• Improved adherence to clinical guidelines reported; 57% of participants had asthma action plan at study end vs 41% at intake
• The proportion considered well-controlled increased by 33% between intake and completion
• Proportion with an asthma-free day in the first month was significantly different from all subsequent months (P<0.01)
Van Sickle et al (2015)57 To determine whether mobile health asthma program could improve asthma outcomes, including frequency of rescue medication use, asthma-free days, and control Prospective, single-arm Asthma 299 12 months • Study participants included both children and adults. Mean/median age was not reported
• 57% of participants reported having an asthma action plan at study end, compared with only 41% at intake
• At study exit, rescue inhaler use declined by 75%, and the proportion of participants with an asthma-free day increased significantly by 39%
Van Sickle et al (2016)56 To determine whether a sensor-enabled, clinically integrated mobile health asthma quality improvement program could reduce the frequency of SABA use, and increase asthma-free days, asthma control and controller medication adherence RCT Asthma 125 6 months • Study participants included only adults. Mean/median age was not reported
• Significant improvements with intervention vs control on all clinical outcomes, including controller medication adherence, daily SABA use, asthma-free days, and asthma control (all P<0.001)
• 21-point improvement in adherence for the intervention

Abbreviations: ACT, Asthma Control Test; cACT, Childhood Asthma Control Test; ER, emergency room; FEF25–75, forced expiratory flow at 25%–75% of the pulmonary volume; ICS, inhaled corticosteroids; NR, not reported; RCT, randomized controlled trial; SABA, short-acting β-agonist.