Thyroid-stimulating hormone levels and suicide attempts in Chinese patients with first-episode drug-naïve major depressive disorder

Table 3 Threshold effect of thyroid-stimulating hormone levels and suicide attempt using a piecewise logistic regression model

Outcome	Suicide attempt [odds ratio (95%CI), P value]
Model I
Linear effect	1.09 (1.01-1.17), 0.0349
Model II
Inflection point (K)	5.43
< K slope 1	0.94 (0.82-1.07), 0.3386
> K slope 2	1.21 (1.08-1.36), 0.0009
Slope 2 - slope 1	1.29 (1.07-1.57), 0.0090
Predicted at K	-1.90 (-2.13 to -1.67)
Log likelihood ratio test	0.009

For exposure: Thyroid-stimulating hormone (μIU/mL). Adjusted for: (1) Age (years); (2) Gender; (3) Diastolic pressure (mmHg); (4) Systolic pressure (mmHg); (5) Hamilton Anxiety Scale; (6) Anti-thyroglobulin (IU/L); (7) Thyroid peroxidase antibody (IU/L); (8) Fasting blood glucose (mmol/L); (9) Total cholesterol (mmol/L); (10) High-density lipoprotein cholesterol (mmol/L); (11) Triglycerides (mmol/L); (12) Low-density lipoprotein cholesterol (mmol/L); (13) Body mass index (kg/m²); and (14) Hamilton Depression Scale continuous.