BACKGROUND: Tuberculous meningitis kills or disables more than half of those a ffected with the disease. Previous studies have been too small to determine whet her adjunctive treatment with corticosteroids can reduce the risk of disability or death among adults with tuberculous meningitis, and the effect of coinfection with the human immunodeficiency virus (HIV) is unclear. METHODS: We performed a randomized, double blind, placebo con trolled trial in Vietnam in patients o ver 14 years of age who had tuberculous meningitis, with or without HIV infectio n, to determine whether adjunctive treatment with dexamethasone reduced the risk of death or severe disability after nine months of follow up . We conducted prespecified subgroup analyses and intention to treat analyses. RESULTS: A total of 545 patients were randomly assigned to groups that received either dexamethasone (274 patients) or placebo (271 patients). Only 10 patients (1.8 percent) had been lost to follow up at nine months of treatment. Treatmen t with dexamethasone was associated with a reduced risk of death (relative risk, 0.69; 95 percent confidence interval, 0.52 to 0.92; P=0.01). It was not associa ted with a significant reduction in the proportion of severely disabled patients (34 of 187 patients [18.2 percent]among survivors in the dexamethasone group vs . 22 of 159 patients [13.8 percent]in the placebo group, P=0.27) or in the pro po rtion of patients who had either died or were severely disabled after nine month s (odds ratio, 0.81; 95 percent confidence interval, 0.58 to 1.13; P=0.22). The treatment effect was consistent across subgroups that were defined by disease s everity grade (stratified relative risk of death, 0.68; 95 percent confidence in terval, 0.52 to 0.91; P=0.007) and by HIV status (stratified relative risk of de ath, 0.78; 95 percent confidence interval, 0.59 to 1.04; P=0.08). Significantly fewer serious adverse events occurred in the dexamethasone group than in the pla cebo group (26 of 274 patients vs. 45 of 271 patients, P=0.02). CONCLUSIONS: Adj unctive treatment with dexamethasone improves survival in patients over 14 years of age with tuberculous meningitis but probably does not prevent severe disabil ity. BACKGROUND: Tuberculous meningitis kills or disables more than half of those a ffected with the disease. Previous studies have been too small small determine whet her adjunctive treatment with corticosteroids can reduce the risk of disability or death among adults with tuberculous meningitis, and the effect of METHODS: We performed a randomized, double blind, placebo controlled trial in Vietnam in patients o ver 14 years of age who had tuberculous meningitis, with or without HIV infectio n, to whether adjunctive treatment with dexamethasone reduced the risk of death or severe disability after nine months of follow up. We conducted prespecified subgroup analyzes and intention to treat analyzes. RESULTS: A total of 545 patients were randomly assigned to groups that received either dexamethasone (274 patients ) or placebo (271 patients). Only 10 patients (1.8 percent) had been lost to follow up at nine months of t It was not associated with tedious reduction of the proportion of severely disabled patients (relative risk, 0.69; 95 percent confidence interval, 0.52 to 0.92; P = 0.01) (34 of 187 patients [18.2 percent] among survivors in the dexamethasone group vs. 22 of 159 patients [13.8 percent] in the placebo group, P = 0.27) or in the pro po rtion of patients who had either died or severely disabled after nine months (odds ratio, 0.81; 95 percent confidence interval, 0.58 to 1.13; P = 0.22). The treatment effect was consistent across subgroups that were defined by disease s everity grade (stratified relative risk of death, 0.68; 95 percent Confidence in terval, 0.52 to 0.91; P = 0.007) and by HIV status (stratified relative risk of de ath, 0.78; 95 percent confidence interval, 0.59 to 1.04; P = 0.08). Significantly less serious reverse events occurred in the dexamethasone group than in the pla cebo group (26 of 274 patients vs. 45 of 271 patients, P = 0.02). CONCLUSIONS: Adj unctive treatment with dexamethasone improves survival in patients over 14 years of age with tuberculous meningitis but probably does not prevent severe disability.