The influence of socio-economic and locational disadvantage on survival after a diagnosis of lung or breast cancer in Western Australia

Abstract

Objectives The effects of demographic, locational and socio-economic disadvantage, and the influence of private health care on five-year mortality rates in patients with lung cancer or after breast cancer surgery in Western Australia were examined. Methods The Western Australian Record Linkage Project was used to extract all hospital morbidity, cancer and death records of all people with lung or breast cancer in Western Australia from 1982 to 1996. Mortality rate ratios after a diagnosis of lung cancer or breast cancer surgery were estimated using Cox regression. Two sets of analyses were carried out: demographically adjusted from 1982 to 1996; and demographically and disadvantage adjusted from 1992 to 1996. Results Overall, 87.7% of lung cancer and 17.8% of breast cancer patients were deceased by five years. Lung and breast cancer patients treated in rural hospitals had higher mortality rates (1992-1996: relative risk (RR) 1.24, 95% confidence interval (CI) 1.07-1.44, and RR 1.20, 95% CI 0.92-1.56, respectively; 1982-1996: RR 1.20, 95% CI 1.11- 1.30, and RR 1.19, 95% CI 1.06-1.33, respectively), whereas location of residence had little effect. Lung and breast cancer patients treated in private hospitals had lower mortality (1992-1996: RR 0.85, 95% CI 0.76-0.95, and RR 0.90, 95% CI 0.77-1.05, respectively; 1982-1996: RR 0.91, 95% CI 0.84-0.97, and RR 0.92, 95% CI 0.85-0.99, respectively), although insurance status was not a factor. Women with breast cancer had significantly worse survival in the more socio-economically disadvantaged groups (1992-1996: RR 1.41 to 1.26; 1982-1996: RR 1.45 to 1.29). Conclusions Survival was poorer in patients treated in the public hospital system, but the possession of private health insurance was not predictive of better outcomes. People treated in rural hospitals had worse survival, whereas location of residence was not an independent factor. Women in more socio-economically advantaged groups who underwent breast cancer surgery had improved survival.