Low adherence impairs the effectiveness of continuous positive airway pressure (CPAP) therapy in patients with obstructive sleep apnoea (OSA), but knowledge on CPAP usage micro-patterns is mostly lacking. Thus, the aim of this study was to analyse usage micro-patterns among patients with suboptimal CPAP adherence. We analysed CPAP usage datasets comprising the initial 31 nights of therapy. By employing a threshold of 4 h usage in at least 70% of nights, we subdivided the patients into suboptimal and optimal users. We investigated single CPAP start- and stop-points, and introduced the parameter "interruption-rate", by dividing the amount of therapy interruptions per night by the usage duration per night. This parameter represents the amount of interruptions per 1 h of CPAP usage. Group comparison analysis was performed via t-test, Wilcoxon rank sum-test, and via Chi2-test. We included datasets of 48 suboptimal and 48 optimal users (55.9 ± 11.3 years, 83.3% men) in the analysis. Interruption-rate was significantly higher among suboptimal users, when compared with optimal users (median (quartiles) 0.24 (0.14/0.45) versus 0.15 (0.05/0.28), p < 0.001∗). Suboptimal users were more likely to report that CPAP reduced their sleep quality, waked them up at night, and that CPAP side effects or problems with the device impaired their adherence. CPAP usage micro-patterns are more fragmented among OSA patients with lower overall adherence. These patterns might result from impaired sleep quality, due to CPAP side effects, and device-associated problems. Copyright © 2020. Published by Elsevier B.V.