Table 2.
Multivariate proportional hazards model of potential predictors of remitted EDS and sustained DS improvement
| Variable | Remitted EDS vs. persistent EDS | Sustained of DS improvement vs. No ESS change | ||
|---|---|---|---|---|
| HR [95% CI]* | P-Value | HR [95% CI]* | P-Value | |
| Living alone, Yes | 1.22 [1.04–1.45] | 0.02 | ||
| Hypnotic intake during the last month, Yes | 0.79 [0.60–1.03] | 0.08 | ||
| Sleep duration (h) | ||||
| ≥8 | 0.98 [0.52–1.83] | 0.19 | ||
| [6–8] | 0.80 [0.44–1.47] | |||
| [6–8] | 0.57 [0.30–1.07] | |||
| <6 | 1 | |||
| Body mass index (kg/m2) | ||||
| <25 | 1.81 [1.08–3.03] | 0.04 | 0.97 [0.78–1.21] | 0.34 |
| [25–30] | 1.13 [0.66–1.94] | 0.86 [0.69–1.08] | ||
| ≥30 | 1 | 1 | ||
| Hypertension, Yes (vs. No) | 1.98 [1.20–3.27] | 0.007 | ||
| Diabetes, Yes (vs. No) | 0.94 [0.70–1.26] | 0.66 | ||
| Neurological disease, Yes (vs. No) | 1.10 [0.89–1.37] | 0.39 | ||
| Change in sleep duration | ||||
| % of decrease (−7.21%)† | 1.07 [0.87–1.31] | 0.41 | ||
| No change | 1 | |||
| % of increase (+9.09%)† | 1.15 [0.93–1.41] | |||
| Change in insomnia severity index | ||||
| % of decrease (−27.27%)† | 3.49 [2.10–5.81] | <0.0001 | 1.23 [0.65–2.32] | 0.49 |
| No change | 1 | 1 | ||
| % of increase (+33.33%)† | 1.79 [1.03–3.11] | 1.13 [0.90–1.43] | ||
| Change in Beck Depression Inventory score | ||||
| % of decrease (−33.33%)† | 1.69 [1.09–2.61] | 0.04 | 1.08 [0.88–1.33] | 0.77 |
| No change | 1 | 1 | ||
| % of increase (+42.86%)† | 1.07 [0.65–1.75] | 1.02 [0.84–1.25] | ||
| Change in chronic pain | ||||
| Decrease | 0.97 [0.50–1.89] | 0.23 | 1.25 [0.94–1.66] | 0.24 |
| No change | 1 | 1 | ||
| Increase | 0.47 [0.20–1.11] | 1.14 [0.87–1.50] | ||
DS, Daytime sleepiness; EDS, Excessive Daytime Sleepiness; ESS, Epworth Severity Scale.
*Variables associated at p < 0.15 in univariate analysis (Table 1) at baseline were included in the model and were adjusted for baseline ESS score and age.
†For a given variable, the numbers in brackets correspond to the lowest (for decrease) or the highest quartile (for increase) of all relative differences between two consecutives evaluations.