Decomposition of Socioeconomic Inequalities in Metastasis, Recurrence, Stage, Grade, and Self-Rated Health of Gastrointestinal Cancer Patients

Abstract

Background: We evaluated the effect of socio-economic status (SES) inequality on metastasis, recurrence, stage, grade, and self-rated health (SRH) in patients with gastrointestinal cancers (GIC). Methods: This cohort study was conducted on 409 patients suffering from GIC (April to October, 2018), who were referred to one of the hospitals of Arak University of Medical Sciences (Arak, Iran). They were entered to the study, using non-random sampling (accessible sampling). The SES was calculated by an asset-based questionnaire. The principle component analysis (PCA) was performed to estimate the household SES. The concentration index (C) was used to measure the SES inequality, and the binary logistic regression was employed to investigate the association of recurrence and metastasis with other variables. The variance analysis was also used to investigate the relationship between SES and other variables. The data were analyzed with Stata (V. 13) software. Results: The total C index for metastasis, recurrence, stage, grade, SRH, and SRH-age was obtained as 0.089 (0.053, 0.121), -0.106 (-0.118, -0.065), 0.073 (0.069, 0.078), 0.035 (0.001, 0.051), 0.018 (0.010, 0.026), and 0.097 (0.063, 0.112), respectively. Moreover, the results of variance analysis showed a significant statistical association between SES and age, marital status, education, job, supplementary insurance, SRH-age, chemotherapy, and surgery (P < 0.05). Conclusions: Regarding the level of SES, the results of this study did not show the inequality in metastasis, recurrence, and stage. However, there was an inequality in grade and SRH by the SES levels in patients with GIC.