Table 2.
Effects of Poor Sleep Burden on Incident Delirium
| Poor Sleep Burden | All Delirium (n = 4 775) | Postoperative Delirium (n = 1 613) | Nondementia-Related Delirium (n = 3 943) | |||
|---|---|---|---|---|---|---|
| HR (95% CI) | p | HR (95% CI) | p | HR (95% CI) | p | |
| Model A | ||||||
| Sleep score* | 1.12 (1.10–1.14) | <.001 | 1.10 (1.07–1.13) | <.001 | 1.14 (1.12–1.17) | <.001 |
| Mild | 1.13 (1.06–1.20) | <.001 | 1.23 (1.01–1.26) | .02 | 1.14 (1.06–1.22) | .002 |
| Moderate | 1.44 (1.34–1.57) | <.001 | 1.33 (1.17–1.53) | <.001 | 1.51 (1.40–1.65) | <.001 |
| Severe | 2.23 (1.98–2.51) | <.001 | 2.03 (1.64–2.51) | <.001 | 2.47 (2.17–2.80) | <.001 |
| Model B | ||||||
| Sleep score* | 1.10 (1.08–1.13) | <.001 | 1.09 (1.06–1.13) | <.001 | 1.14 (1.11–1.16) | <.001 |
| Mild | 1.12 (1.05–1.20) | .003 | 1.12 (1.00–1.25) | .04 | 1.13 (1.06–1.21 | <.001 |
| Moderate | 1.43 (1.33–1.55) | <.001 | 1.31 (1.14–1.50) | <.001 | 1.50 (1.37–1.63) | <.001 |
| Severe | 2.18 (1.93–2.24) | <.001 | 1.99 (1.60–2.48) | <.001 | 2.41 (2.11–2.74) | <.001 |
| Model C | ||||||
| Sleep score* | 1.08 (1.06–1.10) | <.001 | 1.08 (1.05–1.11) | <.001 | 1.12 (1.10–1.14) | <.001 |
| Mild | 1.10 (1.03–1.17) | .003 | 1.10 (0.98–1.22) | .09 | 1.11 (1.03–1.19) | .005 |
| Moderate | 1.37 (1.27–1.48) | <.001 | 1.25 (1.09–1.44) | .001 | 1.42 (1.30–1.55) | <.001 |
| Severe | 2.01 (1.78–2.27) | <.001 | 1.84 (1.48–2.29) | <.001 | 2.17 (1.90–2.48) | <.001 |
| Model D | ||||||
| Sleep score* | 1.07 (1.06–1.09) | <.001 | 1.05 (1.01–1.08) | .005 | 1.07 (1.05–1.09) | <.001 |
| Mild | 1.05 (0.98–1.12) | .18 | 1.06 (0.94–1.19) | .33 | 1.05 (0.97–1.13) | .22 |
| Moderate | 1.18 (1.08–1.28) | .002 | 1.09 (0.94–1.27) | .24 | 1.20 (1.09–1.32) | .002 |
| Severe | 1.57 (1.38–1.80) | <.001 | 1.45 (1.14–1.85) | .0025 | 1.72 (1.49–1.98) | <.001 |
Notes: HR = hazard ratio; 95% CI = 95% confidence interval. Cox proportional hazards models for the continuous sleep score (
*each 1-point increase), and comparing poor sleep burden groups against reference group “none/minimal,” for all delirium cases, postoperative delirium, and nondementia-related delirium subgroups. Model A is our core model adjusting for demographics (age, sex, education, ethnic background, and deprivation). Model B includes Model A plus sleep disorders. Model C includes Model B with physical activity, alcohol consumption, and body mass index. Model D adds on Model C with cardiovascular risk score, reaction time, comorbidities: dementia/Parkinson’s, respiratory disease, gastrointestinal diseases, renal diseases, cancer diagnosis, vitamin D status, and hypnotics. Two-sided p value for HR in comparison with the reference category, without adjustment for multiple comparisons.