(P13) Incidence of tuberculosis and the need of prophylactic treatment in people living with HIV on anti-retroviral therapy, trends in Stockholm 1996-2013

Författare/Medförfattare

Maria Norrby¹, Carolina Wannheden², Anna Mia Ekström³,⁴, Ingela Berggren⁵, Lars Lindquist⁴.

Affiliates

¹ Clinic for Infectious Diseases, Danderyds Hospital, 182 88, Stockholm, Sweden, ² Medical Management Centre, Department of Learning, Informatics, Management and Ethics (LIME), Karolinska Institutet, Tomtebodavägen 18A, 171 77 Stockholm, Sweden, ³ Department of Public Health Sciences, Karolinska Institutet, Tomtebodavägen 18A, 171 77 Stockholm, Sweden, ⁴ Department of Infectious Diseases, Karolinska University Hospital, Huddinge, Sweden, ⁵ Department of Communicable Disease Control and Prevention, Stockholm County Council, Box 17533, 118 91 Stockholm, Sweden.

Abstract

Background:
The aim of this observational cohort study was to study the incidence of and risk determinants for active tuberculosis (TB) in people living with HIV in a low-endemic setting to understand the need of TB chemoprophylaxis in populations where early combination antiretroviral therapy (ART) is fully available.

Methods:
All 2,127 adult (18 years) patients diagnosed with HIV at the Karolinska University Hospital in Stockholm County between 1996 and 2013 were eligible. After exclusion of 259 patients transferred to other clinics, N=1868 were followed until TB diagnosis, death or end of study period. The median follow-up time was 7.9 years (IQR, 3.9–11.5).

Results:
Active TB was diagnosed in 92 patients, corresponding to an incidence rate of 6.2 cases (95% CI 5.1–7.6) per 1 000 person-years with a significant and decline over time since HIV diagnosis. Of these, 66% (n=61), were diagnosed with TB within 3 months and 68% within 6 months of their HIV diagnosis. Only 28 patients diagnosed with active TB were on ART at the time of TB-diagnosis. Out of the 92 diagnosed with TB, 20 had begun ART within two months from their HIV-diagnosis, five of these were diagnosed with TB more than six month after HIV-diagnosis despite early ART initiation. Being a migrant from a TB-endemic region, was the only patient characteristic associated with a significantly higher risk of active TB (hazard ratio 8.84 (95% confidence interval (CI) 3.09–23.61). The number needed to treat to prevent one case of TB among patients in this high-risk group was 22 (95% CI 26–47).

Conclusion:
The incidence of active TB in people living with HIV in Stockholm declined significantly after the introduction of ART. The majority, two-thirds of all active TB cases were diagnosed within six months from HIV-diagnosis, but a significant proportion was also diagnosed later. The therapeutic gain of TB chemoprophylaxis in low endemic settings with full early access to ART should be weighed against costs and side effects.

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