Pharmacogenetic association between NAT2 gene polymorphisms and isoniazid induced hepatotoxicity: Trial sequence meta-analysis as evidence

Hepatotoxicity is a severe problem generally faced by tuberculosis (TB) patients. It is a well-known adverse reaction due to anti-TB drugs in TB patients undergoing long-term treatment. The studies published previously have explored the connection of N-acetyltransferase 2 (NAT2) gene polymorphisms with isoniazid-induced hepatotoxicity, but the results obtained were inconsistent and inconclusive. A comprehensive trial sequence meta-analysis was conducted employing 12 studies comprising 3613 controls and 933 confirmed TB cases using the databases namely, EMBASE, PubMed (Medline) and Google Scholar till December 2017. A significant association was observed with individuals carrying variant allele at position 481C>T (T vs. C: P = 0.001; OR = 1.278, 95% CI = 1.1100–1.484), at position 590G>A (A vs. G: P = 0.002; OR = 1.421, 95% CI = 1.137–1.776) and at position 857G>A (A vs. G: P = 0.0022; OR = 1.411, 95% CI = 1.052–1.894) to higher risk of hepatotoxicity vis-à-vis wild-type allele. Likewise, the other genetic models of NAT2 gene polymorphisms have also shown increased risk of hepatotoxicity. No evidence of publication bias was observed. These results suggest that genetic variants of NAT2 gene have significant role in isoniazid induced hepatotoxicity. Thus, NAT2 genotyping has the potential to improve the understanding of the drug–enzyme metabolic capacity and help in early predisposition of isoniazid-induced hepatotoxicity.