Table 4.

Risk of bias in human trials assessing the role of N-acetylcysteine for traumatic brain injuries.

	Selection bias		Performance bias	Detection bias	Attrition bias	Reporting bias	Other bias
	Random sequence generation	Allocation concealment
Amen et al. (34)
Ranking	High-risk	High-risk	High-risk	Unclear	Unclear	High-risk	High-risk
Explanation	Not randomized	No allocation concealment	No blinding	No information provided	No information provided	Selective results presented	Other drugs used, no dosage, compliance not reported
Hoffer et al. (35)
Ranking	Low-risk	Low-risk	Low-risk	Low-risk	Low-risk	Low-risk	High-risk
Explanation	Randomized	Allocation concealment done	Blinding of participants and assessors	Blinding of outcome assessor	All subjects followed to endpoint	Trial protocol and study reported	Generalizable? (conducted in the military setting)
Clark et al. (36)
Ranking	Low-risk	Unclear	Low-risk	Low-risk	Low-risk	Low-risk	High-risk
Explanation	Randomized	No information provided	Blinding of participants and assessors	Blinding of outcome assessor	All subjects were followed to endpoint	Reported prior publication in clinicaltrials.gov	Small sample size