COPD Patients with chronic hypercapnic respiratory failure; experience respiratory symptoms and physical incapacity that negatively influence health status, which itself is a predictor of frequent hospitalizations and higher mortality [11].

Hence, the principal purpose of the study is to assess the impact of AVAPS treatment in COPD patients with CHRF on health status; through a structured interview incorporates the Short Form 12 (SF-12) over a 6-month duration. The SF-12 has been exhibited to be a valid evaluation tool that enables to calculate the physical well-being and the mental-well being components of HRQOL.

The main findings in this study, treatment with AVAPS, led to significant 6- month improvements in several domains of HRQOL, with the most significant increase seen in the general health domain. The effect is stronger on the physical than the mental aspects of health status. Prior studies in COPD patients with stable hypercapnic respiratory failure have demonstrated that patients receiving home-based NiPPV reported more restful sleep when using AVAPS as compared with conventional NiPPV [12,13,14,15]. However, up to date, no study has consistently addressed the benefit of AVAPS on HRQOL.

Another important consideration in this study is adherence to therapy during the long-term use of AVAPS. In one study, Kelly et al. reported that AVAPS led to one additional hour per night of use compared with conventional PS [5]. Such improvements in adherence could have an impact on patient outcomes [16].

Concerning gasometric parameters, we compared ABG values (PaCO₂, Pa O₂, and HCO3) at baseline and after 6 months of AVAPS treatment. We observed overall ABG alterations in both groups but a significant reduction in PaCO₂ after 6 months in the AVAPS treated group. Crisafulli et al. previously reported improved gas exchange in hypercapnic COPD patients who received AVAPS [6]. Moreover, a recent randomized trial [17] comparing patient satisfaction between (ST/BiPAP with AVAPS) and ST/BiPAP alone in 22 COPD patients; has shown that overall comfort and patient satisfaction was higher in the AVAPS group as an adjunct to standard BiPAP S/T therapy (1.64 ± 2.77 vs. 1.09 ± 3.02). Besides, they found a greater decrease in blood pressure, heart rate, and blood gases with S/T AVAPS group compared with the ST/BiPAP group. Therefore, COPD patients might benefit from the theoretical advantage of a guaranteed tidal volume during nocturnal ventilation.

In our study on COPD patients, it appears noteworthy that the frequency of exacerbation and hospitalization days was reduced in response to AVAPS treatment, although statistical significance was not reached. Thus, these results potentially suggesting a more favourable added benefit if used for a more extended period.

The strengths of this study include its randomized design and the use of the SF-12 questionnaires to assess health status. The SF-12 is one of the most frequently used and valid instrument to evaluate HRQOL.

However, limitations of the present study are; the number of patients was minimal, that the results cannot be generalized to COPD patients with exacerbation, as all included patients were initiated at least 4 weeks after an exacerbation. Therefore, we think that larger sample size and a longer follow up period should be done to test our hypothesis.