Impact of low-dose CT screening for lung cancer on ethnic health inequities in New Zealand: a cost-effectiveness analysis

OBJECTIVE: There are large inequities in the lung cancer burden for the Indigenous Māori population of New Zealand. We model the potential lifetime health gains, equity impacts and cost-effectiveness of a national low-dose CT (LDCT) screening programme for lung cancer in smokers aged 55–74 years with a 30 pack-year history, and for formers smokers who have quit within the last 15 years. DESIGN: A Markov macrosimulation model estimated: health benefits (health-adjusted life-years (HALYs)), costs and cost-effectiveness of biennial LDCT screening. Input parameters came from literature and NZ-linked health datasets. SETTING: New Zealand. PARTICIPANTS: Population aged 55–74 years in 2011. INTERVENTIONS: Biennial LDCT screening for lung cancer compared with usual care. OUTCOME MEASURES: Incremental cost-effectiveness ratios were calculated using the average difference in costs and HALYs between the screened and the unscreened populations. Equity analyses included substituting non-Māori values for Māori values of background morbidity, mortality and stage-specific survival. Changes in inequities in lung cancer survival and ‘health-adjusted life expectancy’ (HALE) were measured. RESULTS: LDCT screening in NZ is likely to be cost-effective for the total population: NZ$34 400 per HALY gained (95% uncertainty interval NZ$27 500 to NZ$42 900) and for Māori separately (using a threshold of gross domestic product per capita NZ$45 000). Health gains per capita for Māori females were twice that for non-Māori females and 25% greater for Māori males compared with non-Māori males. LDCT screening will narrow absolute inequities in HALE and lung cancer mortality for Māori, but will slightly increase relative inequities in mortality from lung cancer (compared with non-Māori) due to differential stage-specific survival. CONCLUSION: A national biennial LDCT lung cancer screening programme in New Zealand is likely to be cost-effective, will improve total population health and reduce health inequities for Māori. Attention must be paid to addressing ethnic inequities in stage-specific lung cancer survival.