Mathematical modelling: what it can offer to sexual health

Mathematical modelling has become an acceptable methodology to overcome som e limitations of experimental studies in medicine. This paper demonstrates how modelling techniques can facilitate our understanding of the impact of clinical and epidemiological factors on sexual health outcomes. Heterogeneo us influences such as the impact of client behaviour on clinical response, and clinician variability in investigation and treatment can be quantified through modelling. Practical dilemmas of resource utilisation, such as cost effective choice of laboratory test or pharmaceuticals, can be addressed f or any given situation. Models can be customised to address local condition s and issues and to estimate clinical efficacy as well as cost effectivenes s, therefore assisting with clinical practice guideline development, and pr oviding economic justification for government funding and health policy. This paper takes as an example a model of the cost effectiveness of general practitioner management of genital chlamydia in New Zealand. This extended mathematical model applied appropriate clinical, behavioural and epidemiol ogical data, and reflected locally appropriate costs and conditions, to det ermine the factors which influence efficacy and cost effectiveness of chlam ydia management in New Zealand. The resulting analysis, a union of mathemat ical modelling, clinical epidemiology and sexual health, was capable of eva luating new tests and changes in disease management. With this single model , information was evaluated for development of clinical guidelines and publ ic health policy. This modelling approach is well suited to answer the diff icult questions facing decision makers in sexual health and other disciplin es into the coming millennium.