For the millions of adults living with refractory chronic cough — a condition that can persist for years and severely erode quality of life — knowing that a treatment produced a statistically detectable change offers cold comfort if the cough still disrupts sleep, conversation, and daily function. A new framework emerging from McMaster University attempts to redefine success not by what patients can barely perceive, but by what they consider genuinely sufficient.
The PROCOUGH cohort enrolled 100 patients (mean age 58, 58% female, median cough duration seven years) and applied European Respiratory Society treatment protocols. Rather than relying on conventional minimally important differences (MIDs), researchers anchored their thresholds to patient-reported sufficiency — specifically, those rating their Global Rating of Change at 6 or 7 and confirming their cough was controlled enough to require no additional treatment. From this anchor group, post hoc analysis derived criteria for Controlled Chronic Cough (ConCC), including a posttreatment 24-hour cough frequency of ≤10 coughs per hour alongside objective and patient-reported severity thresholds. Patients not meeting these criteria were reclassified as still having refractory chronic cough regardless of whether they technically met MID-based response criteria.
This is a meaningful methodological pivot in a field where drug development and clinical benchmarking have long relied on MIDs — by design, the smallest perceptible improvement. The distinction matters because a patient can cross an MID threshold and still cough 20–30 times per hour. With novel antitussive agents like gefapixant and several P2X3 antagonists entering clinical pipelines, having a higher-resolution outcome measure could recalibrate how regulatory and clinical success is judged. The limitations here are real: single-center design, 100-patient cohort, and post hoc derivation all constrain generalizability and causal inference. The thresholds need prospective external validation across diverse populations. Still, as an analytical framework, this represents an incremental but conceptually important advance — shifting the conversation from 'did the patient improve?' to 'is the patient actually well?'