Table 4.
Multivariate proportional hazards model of potential predictors to intermittent excessive daytime sleepiness (EDS) and transient daytime sleepiness (DS) improvement
| Variable | Intermittent EDS vs. persistent EDS | Transient DS improvement vs. No ESS change | ||
|---|---|---|---|---|
| HR [95% CI]* | P-Value | HR [95% CI]* | P-Value | |
| Educational level | ||||
| Secondary level | 1 | 0.93 | ||
| Degree below bachelor | 0.98 [0.66–1.44] | |||
| Bachelor or above | 0.84 [0.55–1.26] | |||
| Living alone, Yes | 1.09 [0.83–1.42] | 0.55 | ||
| Hypnotic intake during the last month, Yes (vs. No) | 0.47 [0.27–0.80] | 0.006 | ||
| Smoking status | ||||
| Not a smoker | 1 | 0.16 | ||
| Current smoker | 1.50 [0.99–2.27] | |||
| Occasional smoker | 1.02 [0.49–2.13] | |||
| Chronic pain, Yes (vs. No) | 0.86 [0.60–1.25] | 0.43 | ||
| Hypertension, Yes (vs. No) | 1.11 [0.75–1.64] | 0.61 | ||
| Endocrine and metabolic disease, Yes (vs. No) | 1.17 [0.78–1.74] | 0.45 | ||
| Diabetes, Yes (vs. No) | 1.29 [0.75–2.22] | 0.37 | ||
| Neurological disease, Yes (vs. No) | 1.13 [0.75–1.72] | 0.56 | ||
| Other diseases, Yes (vs. No) | 0.90 [0.68–1.18] | 0.43 | 1.18 [0.85–1.65] | 0.33 |
| Change in sleep duration | ||||
| % of decrease (−7.21%)† | 1.14 [0.75–1.74] | 0.0007 | ||
| No change | 1 | |||
| % of increase (+9.09%)† | 1.96 [1.37–2.81] | |||
| Change in insomnia severity index | ||||
| % of decrease (−27.27%)† | 2.73 [1.95–3.82] | <0.0001 | 2.10 [0.98–4.49] | 0.11 |
| No change | 1 | 1 | ||
| % of increase (+33.33%)† | 1.30 [0.92–1.83] | 1.91 [1.01–3.59] | ||
| Change in Beck Depression Inventory score | ||||
| % of decrease (−33.33%)† | 1.86 [1.30–2.65] | 0.002 | ||
| No change | 1 | |||
| % of increase (+42.86%)† | 1.11 [0.72–1.70] | |||
| Change in body mass index | ||||
| % of decrease (−2.44%)† | 1.12 [0.77–1.62] | 0.13 | ||
| % of no change | 1 | |||
| % of increase (+3.23%)† | 0.70 [0.46–1.06] | |||
| Change in chronic pain | ||||
| Decrease | 0.82 [0.53–1.28] | 0.46 | ||
| No change | 1 | |||
| Increase | 0.78 [0.48–1.28] | |||
DS, daytime sleepiness; EDS, Excessive Daytime Sleepiness; ESS, Epworth Severity Scale.
*Variables associated at p < 0.15 in univariate analysis (Table 3) 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.