Interventions:
The comparators were appropriately selected as the two most common criteria used for the general population. Alternative assumptions for screening frequency were considered.
Effectiveness/benefits:
: It was not clear whether a systematic review was used to identify the relevant sources of evidence, but these sources were appropriate as country-specific databases report large amounts of data on epidemiological factors and are representative of the whole population. Well-known UK sources were generally used to estimate the risk factors and cardiovascular events over time. The data sources were referenced but their methods were not described, limiting the possibility of judging the validity of the inputs. The methods used to calculate screening performance were given in detail and appear to have been appropriate. No adjustment for quality of life was made, as the authors stated that every life-year gained without a first cardiovascular event was of equal value for each strategy. Thus, cardiovascular disease-free life-years appear to have been a valid benefit measure.
Costs:
The economic analysis only included preventive treatment and screening costs and these were authors’ assumptions and not from any published source. The analysis was illustrative of the alternative cost-effectiveness for various assumed values. The authors justified their exclusion of the cost of inviting people to be seen, as this cost was small and applied equally to both screening strategies. Some costs were varied in the sensitivity analysis. The price year and discounting were not reported, except that discounting of costs and benefits was reported to have little effect.
Analysis and results:
The results were selectively presented, as the total costs and benefits for each strategy were not presented, but intermediate findings were reported for a variety of scenarios, mainly in graphs. The time horizon was not clear, but appears to have been lifetime. Average cost-effectiveness ratios were calculated. The uncertainty was investigated, using a deterministic approach that varied each input one at a time. The results were representative of the UK and appear not to be transferable to other settings, but the authors analysed several alternative scenarios for risk factor cut-off and age cut-off, which gave a broad overview of screening performance in a variety of populations.
Concluding remarks:
The analysis was based on a simulation model that considered various scenarios. Despite the use of several assumptions, the authors’ conclusions appear to be robust.