P58 Indices of TB risk can help stratify recent immigrants registering with a GP for targeted screening

Abstract

Introduction: The burden of tuberculosis (TB) in the UK may only be lowered significantly by identification and treatment of latent infection with M tuberculosis (LTBI) in recent immigrants from moderate (150e499/100 000) and high prevalence (500+/100 000) regions of disease. An approach that focuses immigrant capture to a limited number of GP practices is feasible in our region as the distribution of registrations and TB cases by GP practice is heavily skewed. However, strategies for identifying the most appropriate practices and immigrant subgroups for targeted screening are not known. Aims To evaluate indices of TB risk that may inform targeted screening strategies for newly registering immigrants to Leicestershire (Exeter/Flag-4). Methods: A retrospective analysis was performed of all Flag 4 immigrant registrations between 2000 and 2010 and collated with data for all TB notifications over the same period. The top 10 practices defined by number of registrations (10R), number of TB cases (10TB) and a weighted index [WI=(TB cases/immigrant registrations) 3 TB cases] were identified and compared. Logistic regression was performed to model independent predictors of TB events. TB risk for specified immigrant subgroups was estimated using KaplaneMeier analysis and pair-wise comparisons of risk computed as the rate ratio (95% CI). Results: 564 TB cases were recorded in 34 764 registered immigrants at 148 practices. Independent predictors of TB risk were immigrant age at registration and gender and deprivation index of the GP practice locality. Compared with registration at a non-top 10 practice, the corresponding rate ratios for TB after 5 years at a top 10 practice were 1.32 (95% CI 1.1 to 1.57) for 10R; 1.72 (95% CI 1.44 to 2.1) for 10TB and 1.79 (95% CI 1.5 to 2.14) for 10WI. Compared with the unselected registering immigrant population, the 5 and 10 year TB rates in 10WI practices were significantly higher for immigrants aged 16e35 years but not older adults >35 years (Abstract P58 table 1). (Table presented) Conclusion: TB risk among immigrants newly registering with a GP is heterogeneous. Indices for risk stratification are identifiable that may improve cost-effectiveness of targeted screening.