Effect of High/Low Dose N-Acetylcysteine on Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-analysis

Figures & data

Figure 1.  Flow chart of the literature search and selection (26–36).

Table 1.  Major study characteristics from the 11 studies included in the meta-analysis

Study+year	TSE (2013) (9)	Schermer et al. 2009 (10)	Bachh et al.(2007) (20)	Decramer et al. (2005) (11)	Pela et al. (1999) (7)	Hansen et al. (1994) (8)	Rasmussen et al. (1988) (21)	McGavin et al. (1985) (22)	Boman et al. (1983) (17)	Multicenter Study (1980) (18)	Grassi et al. (1976) (23)
Number of patients (T:C)	58:62	96:96	50:50	256:267	85:84	75:78	59:57	85:96	127:132	371:373	40:40
Mean age (T:C)	71.0:70.8	59.2:59.6	62.6:60.1	62:62	66:66	51.1:51.7	58.8:58.9	64.3:62.6	53.2:51.0		60:62
Dose of NAC	600 mg twice daily	600 mg once daily	600 mg once daily	600 mg once daily	600 mg once daily	600 mg twice daily	300 mg twice daily	200 mg 3 times/day	200 mg twice daily	300 mg twice daily	300 mg twice daily, 3 times a week
Duration of study	1 year	6 months	4 months, followed for 1 year	3 years	6 months	22 weeks	6 months	5 month	6 months	6 months	6 months
COPD severity	Most of themModerate to severe	64% Moderate to severe	Moderate to severe	Moderate to severe	Moderate to severe	Mild or chronic bronchitis	chronic bronchitis	Severe to very severe	—	—	chronic bronchitis
Current smoking (T:C)	15:13	54:49	­ —	120:109	29:19	71:70	—	24:25	—	—	—
ICS treatment (T:C)	43:52	0:0	10:8	182:183	32:35	—	—	19:27	—	—	—
withdraw (T:C)	6:6	44:40	0:0	70:99	2:4	16:8	15:10	13:20	29:27	117:132	6:9
Jadad score	4	4	1	4	2	4	4	4	—	—	3

T:C: treatment group:control group; ICS: Inhaled corticosteroids.

Figure 2.  Forest plot from meta-analysis, including 8 included RCTs, assessing relative risk (RR) of COPD exacerbations as a function of person-seasons.

Figure 3.  Forest plot from meta-analysis, including all 11 included RCTs, assessing relative risk (RR) of the number of patients with at least one exacerbation.

Figure 4.  Forest plot from meta-analysis, including 5 included RCTs, assessing mean difference (MD) of the forced expiratory volume in one second.

Figure 5.  Forest plot from meta-analysis, including 4 included RCTs, assessing relative risk (RR) of the patients with gastrointestinal disorders.