Devices and systems provide methods of detecting a severity change in respiratory insufficiency (RI) or chronic obstructive pulmonary disease (COPD) condition of a patient. In an example embodiment, a detection monitoring device determines one or more severity change indicators based on a measure of supplied pressure or other representative measure determined by the device. The supplied pressure may optionally be determined during pressure treatment that satisfies a target ventilation. The supplied pressure or representative data may be compared to one or more thresholds that are selected to represent a change in the condition of the RI or COPD patient such as an exacerbation of a prior condition. Results of the comparisons may trigger one or more warnings or messages to notify a patient or physician of a pending change to the patient's RI or COPD condition so that the patient may more immediately seek medical attention to treat the condition.