“Leak” is printed on the CPAP report in red if it crosses a threshold and in a calm colour if it doesn’t. What the report doesn’t tell the patient — or the dealer who just handed over the machine — is that the number is a composite of three very different phenomena, CPAP leak types and
CPAP therapy is well-tolerated for most patients after a 2–4 week acclimation period, but a substantial minority CPAP side effects encounter side effects that, if not resolved, become adherence failures. Almost every side effect has a standard clinical solution, and the solutions are not obscure — they involve pressure adjustment, mask swap, humidification tuning, or graduated desensitisation.
A CPAP prescription written is not a CPAP therapy delivered. Between the prescription and the clinical benefit sits a long, thin corridor called adherence, and the published data on how many patients successfully walk through that corridor is sobering. This article summarises the compliance evidence base — how the 4 hours per night, 70% of
Every CPAP user eventually encounters the number: 4 hours a night, on at least 70% of nights, over a rolling 30-day window. That is the compliance threshold used by insurance schemes internationally, by sleep-medicine quality registries, and — where follow-up happens at all — by clinicians assessing whether to continue, modify, or discontinue CPAP therapy.