AEGiS-13IAC: HIV positive patients with recurrent tuberculosis are at increased risk for reinfection but not relapse.

13th International AIDS Conference

Durban, South Africa - July 9-July 14, 2000

HIV positive patients with recurrent tuberculosis are at increased risk for reinfection but not relapse.

Int Conf AIDS 2000 Jul 9-14; 13:(abstract no. MoOrC187)

Sonnenberg P, Murray J, Shearer S, Glynn J, Kambashi B, Godfrey Faussett P
P. Sonnenberg, LSHTM, Infectious Disease Epidemiology Unit, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom, Tel.: +44 181 340 0626, E-mail: p.sonnenberg@lshtm.ac.uk

BACKGROUND: Rates of recurrent tuberculosis (TB), the proportion of recurrent cases attributable to relapse or reinfection and risk factors associated with these mechanisms, may be influenced by the risk of tuberculous infection and the prevalence of HIV infection.

METHODS: We followed a cohort of South African gold mineworkers who had successfully completed treatment for pulmonary TB (n = 326, mean follow-up 705 days, 46% HIV positive), to determine the incidence of recurrence and associated risk factors. Matched DNA fingerprints from the initial and subsequent episodes of TB were compared. Hazard ratios (HR), adjusted for age and other significant risk factors, were determined using Cox regression.

RESULTS: 65 patients (19.9%) had a subsequent TB episode in the follow-up period. The incidence of recurrence was 10.3 per 100 person years overall (95%CI 8.1-13.2) (HIV positive 16.0, HIV negative 6.4) and 9.0 (6.7-12.0) in those recurring after a first episode of TB (HIV positive 16.1, HIV negative 4.1). Matched DNA fingerprints were available on 39/65 recurrences (60%): 25 pairs were identical (relapse) and 14 were different (reinfection). HIV infection was a risk factor for recurrence overall (HR1.9, 95%CI 1.1-3.2), due to it being a strong risk factor for reinfection (19.2, 2.5-147), but not for relapse (0.61, 0.26-1.4). 13/21 (61.9%) HIV positive patients had recurrence due to reinfection, compared with 1/18 (5.6%) HIV negative patients (p = 0.0003). Cavitation at the end of treatment was a risk factor for recurrence (3.8, 2.3-6.5), but more so for HIV negatives than HIV positives (9.2, 3.6-23.5 versus 2.1, 1.0-4.4; p = 0.01). Cavitation was a significant risk factor for relapse (4.2, 1.9-9.4) but not reinfection (2.6, 0.85-7.7).

CONCLUSION: In a setting with a high risk of tuberculous infection and high HIV seroprevalence, HIV infection increases the risk of recurrent TB, mainly due to reinfection. Strategies to prevent recurrent disease should take this into account.

Keywords: AEGIS, Tuberculosis, HIV Infections, HIV Seropositivity, Tuberculosis, Pulmonary, Incidence, Prevalence, Risk Factors, DNA Fingerprinting, Gold, Recurrence, HIV Seroprevalence, Case-Control Studies, Human
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MoOrC187