Noninvasive positive-pressure home ventilation (NIPPHV) improves arterial blood gases, dyspnea and health-related quality of life (HRQL) in patients with restrictive thoracic diseases. Whether these changes persist during the follow-up remains unclear. The aim of this study was to investigate the long-term effects of NIPPHV upon dyspnea, HRQL, lung function and hospitalization rate in 35 patients with kyphoscoliosis and 27 individuals with several neuromuscular disorders. So, we measured dyspnea, HRQL, lung function and nocturnal oxygen saturation (SaO2) before and after 3, 6, 9, 12 and 18 months after NIPPHV. Dyspnea was assessed with the Borg scale and HRQL was measured using the Spanish validated version of the SF-36 questionnaire. The kyphoscoliosis group showed significant improvement of PaCO2 and SaO2 at 3 months and minor dyspnea changes at 6 months after NIPPHV had been started. These patients also showed improved health status in the following categories: "physical role" and "emotional role" at 3 months and in the categories "social functioning", "vitality" and "mental health" at 6 months after NIPPHV; some of these changes persisted at 9, 12 and 18 months. In the neuromuscular group, a significant improvement of SaO2 was observed at 3 months and this persisted for 18 months. Changes of HRQL in this group included a significant improvement in "physical role" at 3 months, "emotional role" and "social functioning" at 6 months and "physical functioning" at 9 months. The hospitalization rate decreased significantly in all patients from a mean annual admission rate of 1.1 (1.4) before NIPPHV to 0.6 (1.1) after 12 months of ventilatory support (P<0.005). We conclude that: (a) NIPPHV had a higher impact on arterial blood gases, dyspnea and health-related quality of life in patients with kyphoscoliosis than in those with neuromuscular disorders; (b) most clinical and functional changes persisted at long term and (c) a significant decrease in the hospitalization rate after NIPPHV occurred in both groups.