Why cough counts in pulmonary fibrosis research.

At the IPF Summit on 30 September 2026, Laura Kütt, PhD, of Vitalograph made the case that cough deserves a place among the core endpoints in pulmonary fibrosis research, and set out what it takes to measure it reliably.

For many people living with idiopathic pulmonary fibrosis (IPF), cough is one of the most persistent and disruptive symptoms, yet trials have traditionally focused on lung function. Laura, who has spent more than four years developing and deploying cough monitoring for clinical trials, explained why objective cough measurement is meaningful in IPF and how to get reliable data from it.

Cough is a real burden in IPF

There is limited data on objective cough counts in IPF, thus clinical drug trials are a good source for quantifying cough burden in patients with IPF. In the PACIFY COUGH trial, where cough was measured by VitaloJAK device made by Vitalograph, IPF patients coughed on average 22 times per hour, the same level seen in refractory chronic cough. Morphine reduced cough frequency by 39.4% compared with placebo. This study highlights the high cough burden that many IPF patients experience, and that the cough burden remains stable over a two-week measurement period (placebo group).

^{PACIFY COUGH: mean awake cough frequency at day 0 and day 14. Adapted from Wu Z. et al., Lancet Respir Med 2024. The VitaloJAK® cough monitor was used to record participant cough.}

Objective cough frequency also reflects how patients feel. A 2025 scoping review in Lancet Digital Health found that, in IPF, cough frequency correlates well with patients' own rating of cough severity (0.6 to 0.8) and with cough-related quality of life underlining that objective cough frequency measures aspect of cough that is meaningful to the patients. However, the correlations are not perfect, Laura noted, because patient-reported outcomes and objective cough frequency measure complementary aspects of the disease.

Measuring cough objectively: capture and analysis

For deployment of objective cough measurement for clinical trials, it is important to understand how the data is measured. Objective measurement has two parts, capture and analysis, and both determine how reliable the endpoint is.

• Capture: Trials typically measure for 24 hours, with at least 20 hours needed for a valid day. Laura cautioned that continuous monitoring is not an endpoint in itself: sponsors still have to decide how many days to measure and what constitutes a valid day, and shorter periods tend to give better compliance across the entire patient population. Devices should be light, discreet and waterproof, capture only the wearer's coughs, and store the audio recordings as source data if the cough count is a primary or secondary endpoint.

• Analysis: Analysis can be done by human counting or with automated tools, however for all analysis what will be counted as a cough has to be clearly defined and documented, since cough sounds vary between patients especially with patients with underlying lung conditions. Both human analysts and machine-learning models should be trained on real-world variability with coughs across diseases captured in real-life settings, and the performance should be validated with the right metrics. Sensitivity and positive predictive value matter more than specificity, because coughs represent a very small amount of time compared with the other sounds and quiet periods of real-world activity, even for people with high cough frequency.

Vitalograph has provided cough endpoints in commercial clinical trials for more than 12 years. At the time of writing this represents more than 57,000 subject recordings, 33 million coughs analyzed and 58 clinical trials including chronic cough, asthma, COPD and IPF. Its cough analysis service using human annotators, which the FDA expects for Phase 3 primary endpoints, follows processes audited and accepted by pharma partners and regulators.

Vitalograph’s ABACAS^® system for automated cough analysis achieved 90.5% median sensitivity and 95.2% positive predictive value in real-life recordings, accuracy Laura described as well suited to exploratory endpoints.

Laura also previewed the VitaloJAK^® Pearl™, a new wearable cough monitor launching in summer 2027. Under 8 cm long and weighing less than 50 g, it is waterproof and pairs a chest sensor for patient-specific cough detection with an air microphone, plus an accelerometer to track wear time. Its docking station enables fast charging and trims non-cough audio, protecting privacy and speeding transmission and uploads.

Detecting treatment effects in IPF

Objective cough data can show clearly whether a therapy works and has been widely used in clinical trials as a primary endpoint in refractory chronic cough, however there are limited number of trials focusing on cough as an endpoint in IPF. A Phase 2b CORAL study for nalbuphine extended release illustrates well how objective cough measurement can be used to study therapeutic effect in IPF. The CORAL study used cough frequency as an endpoint but additionally examined in a post-hoc analysis the effect of the treatment on cough bouts highlighting additional measures of cough than can be derived from objective cough time-point data. In this analysis, for 162 IPF patients, mean daily cough bouts fell by more than half by week 6 on the higher doses, while the placebo group changed far less (Smith et al.,

^{CORAL: mean 24-hour cough bouts by nalbuphine ER dose versus placebo. Smith et al., ATS 2026. Cough data measured by Vitalograph.}

In the Q&A, an audience member suggested pairing cough with measures such as step count or general activity, since coughing patients often become housebound. Laura agreed this is valuable in exploratory research, as a cystic fibrosis study tracking cough alongside activity and sleep has shown (Van Braeckel, Eva, et al.,2026, Journal of Cystic Fibrosis). For regulators, however, she advised keeping the measure focused on cough itself to enable clear interpretation of the effect of a drug on cough.

Cough within a comprehensive endpoint strategy

Cough complements rather than replaces other endpoints. Vitalograph's clinical endpoint solution brings cough monitoring together with patient-reported outcomes, diaries, spirometry and other digital endpoint data in one integrated platform.

Why cough counts

Laura closed with three takeaways: cough is a frequent and burdensome symptom in IPF, objective cough counts track how patients feel, and cough has already been used as an endpoint to demonstrate drug efficacy. For sponsors designing the next generation of pulmonary fibrosis trials, objective cough is an endpoint worth considering.

To discuss objective cough endpoints for your IPF or ILD study, contact Laura Kütt at laura.kutt@vitalograph.com or the Vitalograph Clinical Trials team.