Table 1. Summary of key characteristics of studies under review.
| Author | Guzzetta et al. | Mellor et al. | Tian et al. | Aparicio et al. | Ziv et al. |
| Year | 2011 | 2011 | 2011 | 2006 | 2001 |
| Model Type | Individual Based Model (Stochastic) | Discrete Event (Stochastic) | Systems Dynamics (Deterministic) | Compartment (Deterministic) | Compartment (Deterministic) |
| Contact Structure | Multiple clusters – household, work, school, etc. | Clustered households | Homogeneous | Homogeneous | Homogeneous |
| Model Implementation Of Contact Structure | Spatial network structure | Clustering of HIV and TB infections | N/A | N/A | N/A |
| Other Modelling Elements | Reactivation, re- infection, spatial effects, age | HIV, age, gender, Fast/Slow Latency, Re-infection, Non- infectious tracking | Parallel classes for investigated and un- investigated cases | Primary/Latent exposure classes | Early/Late Latent classes |
| Interventions | Contact tracing proposed but not implemented | Contact Tracing, Targeted active case finding (HIV) | Contact Tracing (approx.) | Contact Tracing (approx.) Screening | Contact Tracing (approx.) Screening |
| Implementation Of Contact Tracing | N/A | Direct simulation | Transition rates between un-investigated and investigated compartments | Increased treatment rates for latent TB | Increased treatment rates for latent and active TB |
| Setting | Low prevalence | High prevalence | Low prevalence | Low prevalance | Theoretical |
| Region | USA | Africa | Canada | USA | Theoretical |
| Lifespan | 80 years | Calculated from life tables | 37 years | Varies (50–110 approx.) | 50 years |
| Constant Population | Yes | Yes | No | No | No |
| Transmissibility | Varies | 10 per person per year (1 in household) | 18.8 per person per year | Varies | 7 per person per year |
| Mean Survival Time with TB | 7.5 years | 3.3 years without HIV 0.3 years with HIV | 27 years | 10 years | 7.2 years |
| Duration of infectious period | 0.3 years* | 2.0 years | 0.5 years | 0.5 years | 1.5 years† |
| Sensitivity Analysis | Variables which could not be directly estimated from data | Analysis conducted for HIV prevalence only | Coefficient and mean time of tracing contacts | Variables which could not be directly estimated from data | None† |
| High Influence Parameters | N/A | HIV prevalence | Contact detection rate | N/A | N/A |
| Validation | Population compared to US census and CDC data | Household and community transmission rates, TB incidence, HIV modeling, age distribution of pop validated against separate sources | None | None | None |
| Recommendations | Agent based models extended to include the effect of contact tracing, immigration; more data required to produce accurate estimates of transmission within households | Strategy of targeting TB control at HIV+ could be cost effect intervention; future modeling should incorporate improvement to social network modeling – either through graphing/ network or introduction of spatial relationships between households | Contact tracing is self- limiting in its cost effectiveness; individual based model with a network structure is next step | Interventions which treat as few as 5% of recent infections | Intervention which treats up to 40% of early LTBI |
| Self-reported limitations | Immigration, social risk factors and genetic risk factors not taken into account. | No cost effectiveness information for comparison with other interventions. | No age, contact structure or vaccination considered. | Does not account for HIV Preventative treatment may not be cost effective for certain targets. | Does not account for HIV High treatment rates for latent infection hard to achieve in practice as tracing majority of infections is difficult. |
*
Mean treatment duration assumed to be 0.5 years.
†
Study cites previous study in which sensitivity analysis was conducted but did not repeat for this study [38].