HIV-prevalence in tuberculosis patients in Germany, 2002-2009: an estimation based on HIV and tuberculosis surveillance data

Abstract

Tuberculosis (TB) and HIV comorbidity is a major challenge in TB prevention and control but difficult to assess in Germany as in other countries, where data confidentiality precludes notifying the HIV status of TB patients. We aimed to estimate the HIV-prevalence in TB patients in Germany, 2002-2009, and to characterize the HIV/TB patients demographically. Data from the long-term observational open multicentre cohort ClinSurv HIV were used to identify incident TB in HIV-positive individuals. We assessed the cohort's coverage for the nationwide HIV-positive population by contrasting ClinSurv HIV patients under antiretroviral therapy (ART) with national HIV patient numbers derived from ART prescriptions (data by Insight Health; available for 2006-2009). The HIV-prevalence in TB patients was calculated as the number of HIV/TB cases projected for Germany over all culture-positive TB notifications. From 2002 to 2009, 298 of 15,531 HIV-positive patients enrolled in the ClinSurv HIV cohort were diagnosed with TB. A 21% cohort coverage was determined. The annual estimates of the HIV-prevalence in TB patients were on average 4.5% and ranged from 3.5% (95%CI 2.3-5.1%) in 2007 to 6.6% (95%CI 5.0-8.5%) in 2005. The most recent estimate for 2009 was 4.0% (95%CI 2.6-5.9%). The 298 HIV/TB patients were characterized by a male-to-female ratio of 2.1, by a median age of 38 years at TB diagnosis, and by 59% of the patients having a foreign origin, mainly from Subsahara Africa. We provide, to our knowledge, the first estimate of the HIV-prevalence in TB patients for Germany by joint evaluation of anonymous HIV and TB surveillance data sources. The identified level of HIV in TB patients approximates available surveillance data from neighbouring countries and indicates a non-negligible HIV/TB burden in Germany. Our estimation approach is valuable for epidemiological monitoring of HIV/TB within the current legal frameworks.

Figure 1. Schematic overview on subpopulations and available data sources in Germany.

Subpopulations of interest (in italic) include PLWH, mostly placed under ART after HIV diagnosis, as well as TB and HIV/TB patients. Data sources (coloured boxes) include national TB notification data restricted to culture-positive cases, ART prescription data by Insight Health, and the ClinSurv HIV cohort. TB notification and ART prescription data capture patients irrespective of their comorbidity status. ClinSurv HIV is the only source systematically capturing both HIV and TB. This schematic is not to scale.

Figure 2. Estimated HIV-prevalence in TB patients in Germany, 2002 to 2009.

Point estimates are presented with 95% binomial exact confidence intervals (CI). The estimated trend of the HIV-prevalence in culture-positive TB patients with 95%CI was determined by negative binomial regression. Underlying data sources include national TB notification data, ART prescription data by Insight Health and the ClinSurv HIV cohort.

Figure 3. Age distribution among individuals with HIV, TB, and HIV/TB.

The HIV and HIV/TB groups refer to individuals enrolled in ClinSurv HIV since 1999; and HIV/TB patients diagnosed with TB from 2002 to 2009. The TB group refers to notified culture-positive TB patients in Germany, 2002 to 2009 (pooled data).

Figure 4. Distribution of foreign origins among individuals with HIV, TB, and HIV/TB stratified by sex.

The HIV and HIV/TB groups refer to individuals enrolled in ClinSurv HIV since 1999, and HIV/TB patients diagnosed with TB from 2002 to 2009 with specified foreign origin in terms of predominant stay. The TB group refers to notified culture-positive TB patients in Germany with specified foreign country of birth, 2002 to 2009 (pooled data).