Dear Editor,

The advances in medical technology and the advent of long-term noninvasive ventilation allowed patients with chronic respiratory insufficiency to benefit from increasing autonomy and quality of life [1]. We read with much interest the recent study by Kleiven et al. [2], in which the authors aimed to describe the health-related quality of life (HRQoL) in patients with chronic hypercapnic respiratory failure under treatment with long-term mechanical ventilation (LTMV) and to ascertain the association between the HRQoL and different respiratory events occurring during LTMV. Their main results showed that, globally, the HRQoL scores, as measured with the Severe Respiratory Insufficiency Questionnaire (SRI), did not differ substantially between the different patient groups, but some respiratory events correlated negatively with specific SRI subscales linked to distinct dimensions of HRQoL. Even though these results are excitingly promising, this study left us with some questions that we consider critical to evaluate and take into account in the following studies.

First, we wonder if it would have been beneficial to collect and analyze data on exacerbations and not to exclude patients with hospital admission due to exacerbation in the previous 3 months, as this may omit important information. We wonder whether a considerable portion of patients may exacerbate due to poor treatment adherence probably stemming from uncontrolled LTMV side effects such as air leaks or increased frequency of undesired respiratory events, including patient-ventilator asynchronies, apneas/hypopneas, and/or hypoventilation [3, 4]. We think that these data should have been collected and analyzed, as possibly describing a relation between respiratory events and a higher occurrence of exacerbations would manifestly impact the patients’ HRQoL and the way we manage them.

Second, and since the authors performed a thorough collection of data including nocturnal polygraphy, we think that it would be relevant to distinguish the type of patient-ventilator asynchronies and to analyze its relation with the different HRQoL subscales [3-5]. Keeping in mind that different types of patient-ventilator asynchronies derive from different causes and may have different ways of resolution, it would be interesting to evaluate the role that they may independently have in the different dimensions of quality of life.

Lastly, the authors present data about the different modes and settings of ventilation observed in this population, but did not try to correlate them with neither the occurrence of asynchronies nor the patients’ quality of life [3, 4]. This would allow the evaluation of the relation between the HRQoL, side effects, respiratory events, and the type/mode of treatment.

We congratulate the authors’ work as this is a study that presents some enriching novel data and key perspectives on the LTMV management and the HRQoL of these patients. Nevertheless, we believe that our remarks are of the utmost clinical relevance and should be taken into account in future studies.

The authors have no conflicts of interest to declare.

The authors declare no funding received.

Pedro Nogueira Costa analyzed the original article and wrote the letter to the editor. João Oliveira Pereira and Antonio M. Esquinas gave additional insight and reviewed the final draft.

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