(P13) Incidence of tuberculosis and the need of prophylactic treatment in people living with HIV on anti-retroviral therapy, trends in Stockholm 1996-2013
Maria Norrby¹, Carolina Wannheden², Anna Mia Ekström³,⁴, Ingela Berggren⁵, Lars Lindquist⁴.
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.
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.
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).
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).
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.