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Table 2 Summary of pooled risk ratios and subgroup analyses of INH efficacy

From: Efficacy of isoniazid prophylactic therapy in prevention of tuberculosis in children: a meta–analysis

Groups Number of studies Number of participants Fixed effects risk ratio(95% CI*) Random effects risk ratio(95% CI) Heterogeneity Chi 2( p)
All studies 8 10,320 0.65(0.47,0.89)# 0.53(0.38,0.80) 18.56(0.00968)
High quality 6 7,845 0.66(0.45,0.98) 0.55(0.35,0.87) 17.55(0.00357)
Low quality 2 2,474 0.53(0.30,0.94) NA 0.47(0.49303)
HIV negative 6 9,509 0.55(0.40,0.75) 0.52(0.36,0.75) 8.57(0.1277)
HIV positive 2 810 0.86(0.41,1.81) 0.58(0.17,1.94) 5.14(0.02335)
TB endemic 5 2,189 0.78(0.55,1.11) 0.67(0.45,0.99) 8.93(0.06281)
TB non endemic 3 8,130 0.40(0.27,0.57) NA 0.05(0.9736)
Primary TB prophylaxis 2 1,353 0.93(0.71,1.21) NA 0.23(0.63119)
Secondary TB prophylaxis 3 5,224 0.44(0.31,0.61) NA 1.05(0.59104)
Excluding studies INH was initiated at age ≤4 months 6 8,966 0.41(0.31,0.55) NA 1.84(0.87086)
High quality excluding studies INH was initiated at age ≤4 months 4 6,492 0.38(0.27.0.53) NA 0.43(0.93385)
INH initiated at age ≤4 months 2 1,353 0.93(0.71,1.21) NA 0.23(0.29)
Age <5 years 3 1,616 0.86(0.57,1.30) 0.77(0.48,1.23) 5.14(0.07644)
Age 5–15 years 2 2,474 0.53(0.30,0.94) NA 0.47(0.49303)
INH for ≥6 months 6 7,845 0.66(0.45,0.98) 0.55(0.35,0.87) 17.55(0.00357)
INH for <6 months 2 2,474 0.53(0.30,0.94) NA 0.47(0.49303)
  1. *Adjusted for heterogeneity when appropriate.
  2. #1 minus the risk ratio gives the protective effect, e.g. for the first row, 0.65 corresponds to 35% protection.