Background:

Herbal medication use is a common health-related behaviour in Malawi and has been identified as a risk factor for several conditions already represented in the TLO model, particularly chronic kidney disease, as well as liver disease, cardiovascular disease, and bleeding disorders. Currently, herbal medication use is not explicitly captured in the Lifestyle module, which may lead to underestimation of risk in relevant disease pathways.

Proposed change:
Introduce herbal medication use as a lifestyle exposure within the Lifestyle module, represented as a categorical or binary variable (e.g. current use / no use), with stratification by rural vs urban residence.

Intended model linkages
The herbal medication exposure would modify transition probabilities or risk parameters in the cmd_chronic_kidney_disease module and in the enhanced lifestyle module

Population stratification
• Rural vs urban residence

Data considerations (placeholders)
• Prevalence of herbal medication use: DHS, local surveys, or published Malawian studies
• Relative risks / hazard ratios: regional or international literature where local data are unavailable