Rapid increase in HIV-related tuberculosis, Chiang Rai, Thailand, 1990-1994

Chiang Rai, the northernmost province of Thailand, has experienced an explosive HIV epidemic since 1989. This study assessed the impact of HIV infection on tuberculosis (TB) in the area. We analyzed the incidence of reported TB in the province from 1982 through 1993 and TB registry data at Chiang Rai Hospital from 1985 through 1994. Following a steady decline in reported TB from 1982 through 1991, the incidence of TB increased sharply after 1991. TB registry data from Chiang Rai Hospital, which began confidential HIV testing in October 1989, indicated a steady and rapid increase in the number and proportion of HIV-seropositive TB patients from four (1.5% of all TB patients) in 1990 to 207 (45.5%) in 1994 (P < 0.001). Compared with HIV-negative TB patients, HIV-positive TB patients were more likely to be men, aged 20-39 years and have extrapulmonary TB (P < 0.001). Treatment completion rates were similar. Twelve months after beginning TB treatment, HIV-positive TB patients had a mortality rate of 68.6% [95% confidence interval (Cl), 62.7-74.3] compared with 10.0% (95% Cl, 8.3-12.1%) in HIV-negative patients (P < 0.001). Thailand and other Asian countries where HIV is spreading rapidly must promptly address the dual epidemic of TB and HIV in order to reduce preventable morbidity and mortality.