3.3 NIV usage and effect by age
Domiciliary data was compared across age groups, as well as, between and within cohorts (Figure 2). There was an increase in the percentage days used in the DS age group two relative to their non-DS comparators. Significantly increased usage was observed in the eldest DS age group relative to its corresponding age group one. There were no statistical differences observed in the usage parameter of percent days used >4hours, between DS and non-DS cohorts in any age group. However, greater use was observed in the non-DS eldest cohort relative to its corresponding younger age groups. Similar trends were observed in the parameter of average use per night.
The clinical outcome of AHI was significantly higher in the youngest age group within the DS cohort relative to the non-DS, an AHI of 6.38 ± 0.74 was observed in the youngest DS age group compared with 4.74 ± 0.40 in the age-matched non-DS group, with p=0.041.
Within the eldest two age bands, there was significantly greater system leak in the DS cohort relative to their age-matched counterparts, 45.34 ± 3.39L/min versus 34.88 ± 1.72L/min (p=0.003) in age group two and 42.88 ± 3.60L/min versus 31.86 ± 2.56L/min (p=0.013) in those aged greater than 10 years. The non-DS cohort showed a significant decrease in system leak as age increased; this trend was not mirrored in the DS group. A similar trend was also observed in the functional parameter of percentage of time at excess leak. Comparison across the 5-10 year age group shows a mean time at excess leak of 22.41% in those with DS and 14.01% in the non-DS group, with p=0.023. Similarly, in those aged greater than 10 years old greater time at leakage was observed in the DS cohort, 23.78% compared to 11.86%, p=0.024.