Reference products and why people stop using them — pediatric persistent asthma home monitoring

1. Summary

The domain dossier's own §5 already surveyed the peak-flow/spirometry hardware market (FDA product codes BZG and BZH) and found no patient-level adherence or dropout study for that hardware class. This report looks at the adjacent reference-product class actually put through registered pediatric trials — inhaler-attached adherence sensors — and at the one federal registry the dossier flagged as unreached. Two FDA-cleared sensor products, Reciprocal Labs' Propeller line and Cohero Health's SpiroThor/HeroTracker, are the devices behind the pediatric persistent-asthma trials found here [9][10]. In the one such trial with posted results — Connecticut Children's Medical Center's HeroTracker study, ages 8-17, diagnosed persistent asthma — six months of sensor-based reminders moved medication adherence only from a mean Proportion of Days Covered of 0.33 (control) to 0.39 (intervention), both well under full coverage [3]. A companion Propeller feasibility study in the same population (ages 10-18) enrolled 50 children but has posted no results [4], a third pediatric inhaler-sensor trial was withdrawn before enrolling anyone for lack of funding [5], and a fourth is currently recruiting [6]. A larger, non-affiliated national RCT of sensor-based inhaler monitoring in a broader pediatric population found the sensor arm had significantly more emergency-department visits and hospitalizations than usual care despite a modest gain in Asthma Control Test scores [1], and a 2025 systematic review of 12 such trials (2,483 children and adults) put the median device failure rate at 12% [2]. FDA's MAUDE database — unreachable by any connector in this repo but reachable directly — logs 19 malfunction/injury reports against diagnostic spirometers (BZG) in the 2016-2026 window and zero against peak-flow meters (BZH) in the same window [7][8].

2. What Changed

_Baseline (v1). No prior version; this establishes the starting point for future diffs._

3. Details

The reference-product class actually tested in this population: inhaler-attached sensors, not peak-flow hardware

The dossier's BZG/BZH clearance sweep is the right survey of home spirometry/peak-flow hardware, but every registered pediatric-persistent-asthma trial located this pass tests a different product class: a sensor that clips onto or replaces an inhaler and reports each actuation. Reciprocal Labs Corporation's Propeller Sensor for Symbicort (K192724, decided 2020-03-26) and Cohero Health, LLC's SpiroThor (K150137, decided 2015-05-27) are both FDA-cleared Class II devices in this family [9][10]. These, not a spirometer or peak-flow meter, are the hardware behind every trial below.

The one completed pediatric-persistent-asthma trial with posted results

ClinicalTrials.gov NCT03734861, sponsor Connecticut Children's Medical Center, enrolled 75 children ages 8-17 with a documented diagnosis of persistent asthma prescribed an inhaled corticosteroid, randomized to Cohero Health's BreatheSmart/HeroTracker sensor system (n=50) or standard of care (n=25) [3]. Posted results, retrieved directly from the registry's structured results module: mean Proportion of Days Covered (PDC) at 6 months was 0.39 (SD 0.34) in the sensor arm versus 0.33 (SD 0.30) in the control arm [3][sponsor-reported]. Both figures describe a child covered by controller medication on roughly a third to two-fifths of days — a low baseline adherence level that a consumer-facing sensor and reminder app moved only marginally. The registry's own participant-flow data records zero dropouts from either study arm (50/50 and 25/25 completed), so the low PDC reflects non-adherence to the medication regimen while enrolled, not attrition from the study itself [3][sponsor-reported].

A companion feasibility study, and the programs that did not produce results

ClinicalTrials.gov NCT03648450, same sponsor, ages 10-18, inclusion criterion "history of persistent asthma (defined as prescribed a controller medication)," tested Propeller electronic monitoring device feasibility and acceptability. Status COMPLETED, enrollment 50 (actual), but no results have been posted to the registry [4][sponsor-reported]. ClinicalTrials.gov NCT02426814, sponsor CoheroHealth (the device manufacturer itself), targeted ages 11-19 with an asthma diagnosis on a controller inhaler; status WITHDRAWN, enrollment 0, whyStopped (verbatim): "Lack of funding" [5][sponsor-reported]. This is a second, distinct revealed-behaviour data point alongside the three pediatric home-RPM programs the domain dossier's §5 already catalogued (Philips' ALPACA withdrawal for "refocus of business," Weill Cornell's termination for partner staffing, AeviceMD not yet recruiting) — of six pediatric home-asthma-monitoring research efforts now identified across the dossier and this report, three ended or never enrolled for a reason unrelated to clinical performance, one posted results showing marginal effect, and two remain open. ClinicalTrials.gov NCT06820593, sponsor Ann & Robert H. Lurie Children's Hospital of Chicago, ages 4-17 with "persistent or uncontrolled asthma," is currently recruiting toward an estimated 80 parent-child pairs to test an mHealth app plus digital sensors with a dedicated "asthma coordinator" role; no results posted [6][sponsor-reported].

A non-affiliated, larger-population signal: sensor feedback and higher acute care use

PMID 33386336, Pediatrics (2021-01), a multicenter NIH-funded RCT independent of the sensor manufacturers above, randomized 252 caregiver-child dyads to inhaler-sensor monitoring with clinician feedback (n=125) or control (n=127) [1][single-source]. Reported findings, quoted from the structured abstract: Asthma Control Test scores rose more in the intervention arm (Δ = 2.2, SE 0.6, P<.01), but "adjusted rates of emergency department visits and hospitalizations among the intervention were significantly greater" than control (incidence rate ratio 2.2 for ED visits, 3.4 for hospitalizations, both P<.01) [1][single-source]. The authors' own conclusion: "Higher health care use was observed among the intervention participants relative to the control, indicating further refinement is warranted" [1][single-source].

The device-reliability record across a larger evidence base

PMID 40312010, a 2025 systematic review and meta-analysis prepared for an AAAAI/ACAAI severe- asthma practice-parameter guideline, pooled 12 randomized trials enrolling 2,483 children (ages 4-17) and adults using patient-facing digital inhalers [2][single-source]. Quoted directly: "The median of mean device failure rate was 12%, with trials reporting issues regarding sensor synchronization with smartphones (very low certainty)," and "one trial reported a protected health information exposure while using patient-facing digital inhalers" [2][single-source]. The same review found digital inhalers "probably improve asthma control" on average but with only low-to-moderate certainty evidence and no measurable gain in quality of life [2][single-source].

MAUDE — the registry the dossier flagged as unreached

FDA's device/event (MAUDE) database, queried directly by URL rather than through a repo connector, records 19 reports in product code BZG (diagnostic spirometer, 21 CFR 868.1840) with a received date in the 2016-09-04 to 2026-09-02 window — 16 coded Malfunction, 3 coded Injury — and zero reports in product code BZH (peak flow meter, 21 CFR 868.1860) in the same window [7][8]. Brand names in the BZG reports (Microlab, Spirobank II, VMAX, SpiroPerfect, and several generic pulmonary-function-test and cardiology-suite listings) are overwhelmingly adult clinical hardware; patient age was blank or unrecorded in the individual reports read for this pass, so no pediatric-specific complaint could be isolated from the aggregate count.

4. Sources

[1] "Sensor-Based Electronic Monitoring for Asthma: A Randomized Controlled Trial" — Pediatrics (published 2021-01; accessed 2026-09-01). PMID 33386336 — https://pubmed.ncbi.nlm.nih.gov/33386336/ [peer-reviewed] [2] "Patient-Facing Digital Inhalers for Asthma: A Systematic Review and Meta-Analysis" — The Journal of Allergy and Clinical Immunology: In Practice (published 2025-07; accessed 2026-09-01). PMID 40312010 — https://pubmed.ncbi.nlm.nih.gov/40312010/ [peer-reviewed] [3] ClinicalTrials.gov NCT03734861 — "The Study is Enrolling Kids From 8 to 17 Years Old. The BreathSmart Device Attaches to the Inhaler to Measure Adherence," sponsor Connecticut Children's Medical Center, status COMPLETED, hasResults true, results and participant-flow data retrieved from the registry's structured API record (last update 2023-04-07; accessed 2026-09-01). NCT03734861 — https://clinicaltrials.gov/study/NCT03734861 [trial-registry] [4] ClinicalTrials.gov NCT03648450 — "Feasibility and Acceptability of the Propeller Monitoring System in Children With Persistent Asthma," sponsor Connecticut Children's Medical Center, status COMPLETED, hasResults false, enrollment 50 (actual) (last update 2023-09-18; accessed 2026-09-01). NCT03648450 — https://clinicaltrials.gov/study/NCT03648450 [trial-registry] [5] ClinicalTrials.gov NCT02426814 — "Assessment of a Mobile Intervention to Increase Adherence to Asthma Medication Among Adolescents," sponsor CoheroHealth, status WITHDRAWN, enrollment 0 (actual), whyStopped "Lack of funding" (last update 2023-07-27; accessed 2026-09-01). NCT02426814 — https://clinicaltrials.gov/study/NCT02426814 [trial-registry] [6] ClinicalTrials.gov NCT06820593 — "Technology-Enhanced Asthma Care in Children at Clinic and Home Study," sponsor Ann & Robert H. Lurie Children's Hospital of Chicago, status RECRUITING, enrollment 80 (estimated) (last update 2025-09-10; accessed 2026-09-01). NCT06820593 — https://clinicaltrials.gov/study/NCT06820593 [trial-registry] [7] openFDA device/event (MAUDE) database, product code BZG "Spirometer, Diagnostic," 21 CFR 868.1840, records with date_received 2016-09-04 to 2026-09-02 (queried and accessed 2026-09-01). 21 CFR 868.1840 — https://api.fda.gov/device/event.json?search=device.device_report_product_code:BZG+AND+date_received:%5B20160904+TO+20260902%5D [federal-registry] [8] openFDA device/event (MAUDE) database, product code BZH "Meter, Peak Flow, Spirometry," 21 CFR 868.1860, records with date_received 2016-09-04 to 2026-09-02 — zero records returned (queried and accessed 2026-09-01). 21 CFR 868.1860 — https://api.fda.gov/device/event.json?search=device.device_report_product_code:BZH+AND+date_received:%5B20160904+TO+20260902%5D [federal-registry] [9] FDA 510(k) K192724 — Propeller Sensor for Symbicort, Reciprocal Labs Corporation (decided 2020-03-26; accessed 2026-09-01). K192724 — https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm?ID=K192724 [federal-registry] [10] FDA 510(k) K150137 — SpiroThor, Cohero Health, LLC (decided 2015-05-27; accessed 2026-09-01). K150137 — https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm?ID=K150137 [federal-registry]

5. Sourcing & Gaps

Well established: The MAUDE event counts and product-code composition for BZG and BZH [7][8], and the two 510(k) clearance records for the sensor devices behind the trials above [9][10], each rest on a single federal registry — the canonical source for that fact — and are stated plainly rather than marked, following the same convention the domain dossier and this domain's other reference-products passes already use for individually-verified registry entries.

Thin: PMID 33386336's outcome comparison and PMID 40312010's pooled failure-rate and guideline-development findings each rest on exactly one publication and carry [single-source] throughout — the ED-visit/hospitalization finding has not been independently replicated in a second published pediatric trial that this pass located, and the 12% device-failure figure is itself already a meta-analytic pool rather than a single trial, but it is still one document. Every quantity drawn from NCT03734861, NCT03648450, NCT02426814 and NCT06820593 carries [sponsor-reported]: three of the four have posted no results at all, and the fourth's posted PDC figures are the sponsor's own registry submission, not an independently corroborated finding.

Rescoped from class 3: The unanswerable question behind this section is "would children and families actually use an inhaler-sensor or peak-flow device consistently enough to matter clinically?" Its revealed-behaviour twin, per docs/research-lane-spec.md §3.1, is answered here as: in the one pediatric persistent-asthma trial that measured it, sensor-prompted adherence reached a mean 39% of days covered against a 33% control baseline [3][sponsor-reported]; in a larger non-affiliated RCT, sensor feedback raised a symptom-control score but coincided with more emergency care, not less [1][single-source]; and of six registered US pediatric home-asthma- monitoring research programs identified across the domain dossier and this report, three ended or never enrolled for a reason stated as funding or staffing, not device rejection.

Out of scope: CPT descriptors for any RPM or remote-monitoring billing code named elsewhere in this domain (AMA-licensed). Device pricing for the Propeller or HeroTracker sensor lines (no connector and no pricing page was retrieved this pass). fda.gov guidance documents (intermittent bot mitigation). Any jurisdiction outside the US (no connector exists).

Not searched vs. not found: Two further direct PubMed queries this pass — "smart inhaler pediatric asthma discontinuation dropout" and "peak flow meter home monitoring children asthma compliance" — each returned zero records, independently reconfirming with fresh phrasing the domain dossier's own finding that no patient-level peak-flow/spirometry adherence-dropout cohort exists in PubMed under the terms tried; this is not found, not merely not searched. The full narrative text of all 19 individual BZG MAUDE reports was not read this pass — only the structured event-type and brand-name fields were reviewed, so specific pediatric-context failure narratives (as opposed to the aggregate Malfunction/Injury counts) were not searched for within those 19 records.

[inference] The pattern across the six registered trials — every one built around an inhaler-attached medication-adherence sensor rather than a peak-flow or spirometry device — suggests that academic and industry sponsors have found medication-adherence tracking more tractable to fund and register as a pediatric asthma home-monitoring intervention than lung- function self-monitoring, even though the domain dossier's own BZG/BZH clearance sweep shows the hardware side of spirometry/peak-flow is, if anything, the more crowded commercial product category. This is this report's own synthesis, not stated by any source above.

6. Claim Candidates