Table 2.

 Risk of 30 day intracranial haemorrhage with combined use of antidepressants and non-steroidal anti-inflammatory drugs (NSAIDs), compared with antidepressant use without NSAIDs, in propensity based matched cohort

Subgroup	Antidepressants only				Antidepressants + NSAIDs			Hazard ratio (95% CI)		P value
	Sum of person years	No of events	Incidence rate per 1000 person years* (95% CI)		Sum of person years	No of events	Incidence rate per 1000 person years* (95% CI)	Unadjusted	Adjusted†
Overall	106 858	169	1.6 (1.36 to 1.84)		99 978	573	5.7 (5.28 to 6.22)	1.9 (1.69 to 2.24)	1.6 (1.32 to 1.85)	<0.001
Antidepressant exposure
TCA	37 803	57	1.5 (1.16 to 1.95)		53 017	307	5.8 (5.18 to 6.48)	2.2 (1.75 to 2.66)	1.7 (1.33 to 2.13)	0.770‡
The rest	69 055	112	1.6 (1.35 to 1.95)		46 961	266	5.7 (5.02 to 6.39)	2.3 (1.86 to 2.83)	1.6 (1.27 to 2.03)
SSRI	27 165	35	1.3 (0.93 to 1.79)		12 002	82	6.8 (5.50 to 8.48)	3.4 (2.86 to 3.98)	1.4 (1.17 to 1.72)	0.678‡
The rest	79 693	134	1.7 (1.42 to 1.99)		87 977	491	5.6 (5.11 to 6.10)	2.5 (2.14 to 2.98)	1.5 (1.27 to 1.86)
SNRI	3255	14	4.3 (2.55 to 7.26)		2715	12	4.4 (2.51 to 7.78)	0.5 (0.43 to 0.58)	0.4 (0.32 to 0.46)	0.190‡
The rest	103 603	155	1.5 (1.28 to 1.75)		97 264	561	5.8 (5.31 to 6.27)	2.3 (2.02 to 2.70)	1.5 (1.31 to 1.83)

SNRI=serotonin-norepinephrine reuptake inhibitors (including duloxetine, milnacipran, and venlafaxine); SSRI=selective serotonin reuptake inhibitors (including citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, and sertraline); TCA=tricyclic antidepressants (including amitriptyline, amoxapine, clomipramine, dothiepin (dosulepin), imipramine, nortriptyline, and quinupramine).

*Incidence rate=(No of events/sum of person years)×1000; 95% CI calculated assuming Poisson distribution.

†Adjusted for dementia, warfarin, heparin group, and steroids as time varying covariates, using matched Cox regression models; death was treated as competing risk.

‡P value for interaction.