Table 5.
Logistic regression models predicting bipolar II disorder. P < 0.05 are shown in bold. Abbreviations: AIC = Akaike Information Criterion; CI = confidence interval; OR = odds ratio; ref = reference category
| A. Full multivariate model (AIC = 871.39) | B. Stepwise selected model (AIC = 862.13) | |||||
|---|---|---|---|---|---|---|
| Variables | Estimate | OR (95% CI) | p | Estimate | OR (95% CI) | p |
| (Intercept) | -2.165 | 0.11 (0.04–0.32) | < 0.001 | -2.001 | 0.14 (0.06–0.31) | < 0.001 |
| Age (years) | 0.012 | 1.01 (0.98–1.04) | 0.387 | - | - | - |
| Sex [ref = female] | -0.159 | 0.85 (0.59–1.22) | 0.387 | - | - | - |
| Age at onset of mania or hypomania (years) | 0.012 | 1.01 (0.99–1.04) | 0.367 | 0.020 | 1.02 (1.00-1.04) | 0.012 |
| Illness duration (years) | -0.009 | 0.99 (0.96–1.02) | 0.553 | - | - | - |
| Predominant polarity [ref = balanced] | ||||||
| Depressive | 0.396 | 1.49 (0.89–2.49) | 0.133 | - | - | - |
| Manic | -0.543 | 0.58 (0.26–1.31) | 0.189 | - | - | - |
| Number of lifetime isolated (hypo)manic episodes [ref = two episodes] | ||||||
| None | 0.669 | 1.95 (0.94–4.07) | 0.074 | 1.017 | 2.76 (1.41–5.43) | 0.003 |
| One episode | 0.604 | 1.83 (1.01–3.31) | 0.046 | 0.81 | 2.25 (1.29–3.91) | 0.004 |
| Multiple recurrence (3 to 6 episodes) | -0.124 | 0.88 (0.48–1.63) | 0.690 | -0.296 | 0.74 (0.42–1.32) | 0.309 |
| Highly recurrent (hypo)mania (7 or more) | 0.381 | 1.46 (0.64–3.35) | 0.367 | -0.134 | 0.87 (0.46–1.67) | 0.683 |
| Number of lifetime isolated depressive episodes [ref = recurrent depression (2 to 3 episodes)] | ||||||
| None | -0.687 | 0.50 (0.15–1.65) | 0.256 | -1.207 | 0.30 (0.11–0.81) | 0.017 |
| One episode | -0.285 | 0.75 (0.37–1.53) | 0.433 | -0.477 | 0.62 (0.33–1.17) | 0.138 |
| Multiple recurrence (4 to 7 episodes) | 0.928 | 2.53 (1.35–4.75) | 0.004 | 0.962 | 2.62 (1.61–4.24) | < 0.001 |
| Highly recurrent depression (8 or more episodes) | 1.515 | 4.55 (1.91–10.86) | 0.001 | 1.448 | 4.25 (2.38–7.59) | < 0.001 |
| Number of lifetime illness episodes (including multiphasic cycles, mixed episodes, continuous cycling) [ref = average number of episodes (5 to 9 episodes)] | ||||||
| Low number of episodes (1 to 4 episodes) | 0.181 | 1.20 (0.61–2.35) | 0.600 | - | - | - |
| High number of episodes (10 to 15 episodes) | -0.256 | 0.77 (0.41–1.47) | 0.433 | - | - | - |
| Very high number of episodes (16 or more) | -0.518 | 0.60 (0.22–1.60) | 0.304 | - | - | - |
| Frequency of episodes [ref = rapid cycling (more than 4 episodes per year)] | ||||||
| Low recurrence (at most every 4 years) | -0.119 | 0.89 (0.44–1.80) | 0.742 | 0.001 | 1 (0.55–1.83) | 0.997 |
| Average recurrence (at most every 2 years) | -0.204 | 0.82 (0.45–1.46) | 0.493 | -0.131 | 0.88 (0.51–1.5) | 0.631 |
| High recurrence (at most every year) | -0.579 | 0.56 (0.31–1.03) | 0.061 | -0.52 | 0.59 (0.34–1.05) | 0.072 |
| Very high recurrence (more than 1 episode/year) | -0.806 | 0.45 (0.22–0.92) | 0.028 | -0.798 | 0.45 (0.22–0.91) | 0.026 |
| Lifetime history of multiphasic cycles [ref = absent] | -0.376 | 0.69 (0.45–1.04) | 0.076 | -0.445 | 0.64 (0.43–0.95) | 0.027 |