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0 0.5 1 1.5 2+ Mortality 35% Improvement Relative Risk N-acetylcysteine  Alam et al.  META ANALYSIS Favors N-acetylcysteine Favors control

N-acetylcysteine reduces severity and mortality in COVID-19 patients: A systematic review and meta-analysis

Alam et al., Journal of Advanced Veterinary and Animal Research, doi:10.5455/javar.2023.j665
Jun 2023  
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14th treatment shown to reduce risk in February 2021
*, now known with p = 0.000034 from 24 studies, recognized in 3 countries.
Lower risk for mortality, hospitalization, and cases.
No treatment is 100% effective. Protocols combine complementary and synergistic treatments. * >10% efficacy in meta analysis with ≥3 clinical studies.
3,800+ studies for 60+ treatments.
Systematic review and meta analysis showing lower mortality and severity with N-acetylcysteine treatment.
Currently there are 24 N-acetylcysteine studies and meta analysis shows:
Mortality31% lower [13‑44%]
Ventilation6% lower [-25‑29%]
ICU admission7% lower [-16‑26%]
Hospitalization11% lower [6‑17%]
Cases26% fewer [20‑32%]
risk of death, 35.0% lower, RR 0.65, p < 0.001.
Effect extraction follows pre-specified rules prioritizing more serious outcomes. Submit updates
Alam et al., 30 Jun 2023, peer-reviewed, 6 authors. Contact:,
This PaperN-acetylcys..All
N-acetylcysteine reduces severity and mortality in COVID-19 patients: A systematic review and meta-analysis
Mohammad Zahangeer Alam, Mohammad Nazmol Hasan, Zannatul Maowa, Fahima Khatun, K Nazir, Mohammad Zahangeer Alam
Journal of Advanced Veterinary and Animal Research, doi:10.5455/javar.2023.j665
Objectives: Recent clinical studies suggest that oxidative stress is one of the key players in the pathogenesis of coronavirus disease 2019 (COVID-19), and N-acetylcysteine (NAC), a potent antioxidant, has been shown to improve clinical outcomes in COVID-19 patients. We conducted a systematic review and meta-analysis of the literature published on the therapeutic intervention of NAC on COVID-19 infection. Methods: We searched PubMed, Google Scholar, and Science Direct. We identified and screened eight studies with 20,503 participants, including 2,852 in the NAC-treated group and 17,651 in the placebo group, which reported the effect of NAC on COVID-19 infection. A meta-analysis was performed using forest plots under fixed effect estimates based on the standardized mean difference (SMD) and risk ratio (RR). Results: Pooled analysis showed that NAC was associated with lower mortality in patients with COVID-19 compared with the placebo group [RR, 0.65; (95% CI: 0.56 to 0.75); p < 0.0001]. Similarly, C-reactive protein (CRP) [SMD, -0.32; (95% CI: -56 to -0.09); p = 0.0070] and D-dimer [SMD, -0.35, (95% CI: -0.59 to -0.10; p = 0.0062] levels were significantly decreased, and the oxygenation marker, PaO 2 /FiO 2 ratio, was increased in the NAC-treated group compared with the placebo group [SMD, 0.76; (95% CI: 0.48 to 1.03); p < 0.0001]. Conclusion: Although the number of included studies was minimal, this meta-analysis suggests that NAC may have a positive effect on COVID-19 outcomes, specifically, a significant decrease in CRP and D-dimer levels and a significant increase in oxygen saturation, which decreased mortality. We have also presented a comprehensive review of the role and mechanisms of NAC in patients with COVID-19.
Conflict of interests The authors declare that there is no conflict of interest in this paper. Authors' contributions Mohammad Shah Alam was involved in the conception, data collection, drafting, intellectual reviewing, and overall article supervision. Mohammad Nazmol Hasan was involved in data collection, curation, and analysis. Mohammad Zahangeer Alam, KHM Nazmul Hussain Nazir, Fahima Khatun, and Zannatul Maowa assisted in editing the article.
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