JMIR Publications

ABSTRACT

Background:

Screening adherence is important in reducing colorectal cancer incidence and mortality. Disparity in colorectal cancer (CRC) screening adherence was observed in different socioeconomic status (SES) populations, but the direction and strength of the association remained unclear.

Objective:

We aimed to systematically review all the observational studies that have analyzed the association between SES and adherence to organized CRC screening based on fecal occult blood tests (FOBT).

Methods:

We systematically reviewed the studies in PubMed, Embase and Web of Science from inception of database up until 7 June 2023 and reference lists of relevant reviews. Individual SES, neighborhood SES and small-area SES were included, while any SES aggregated by geographic areas larger than neighbors were excluded. Studies assessing SES with any index or score combining indicators of income, education, deprivation, poverty, occupation, employment, marital status, cohabitation and others were included. A random effect model meta-analysis was carried out for pooled odds ratio (OR) and relative risk (RR) for adherence related to socioeconomic status.

Results:

10 studies, with a total of 3,542,379 subjects and an overall adherence rate of 64.9% were included. Compared with low SES, high SES was associated with higher adherence (unadjusted OR=1.73, 95%CI=1.42-2.10; adjusted OR=1.53, 95%CI=1.28-1.82). In the subgroup of non-individual level SES, the adjusted association was significant (OR=1.57, 95%CI=1.26-1.95). However, the adjusted association was insignificant in the subgroup of individual-level SES (OR=1.46, 95%CI=0.98-2.17). As for subgroups of the year of print, not only was the unadjusted association significantly stronger in the subgroup of early studies (OR=1.97, 95%CI=1.59-2.44) than in late studies (OR=1.43, 95%CI=1.31-1.56), but also the adjusted one was significantly stronger in the early group (OR=1.86, 95%CI=1.43-2.42) than the late group (OR=1.26, 95%CI=1.14-1.39), which was consistent and robust. Despite not being statistically significant, the strength of the association seemed lower in studies that did not adjust for race/ethnicity (OR=1.31, 95%CI=1.21-1.43) than the overall estimate (OR=1.53, 95%CI=1.28-1.82), and the strength of the association between SES and adherence seemed lower when the adherence rate was low or when SES was the focus of the studies (unadjusted OR=1.53, 95%CI=1.15-2.03; adjusted OR=1.32, 95%CI=1.18-1.48) than not (unadjusted OR=1.91, 95%CI=1.37-2.65; adjusted OR=1.65, 95%CI=1.18-1.48).

Conclusions:

Higher SES population had higher adherence to FOBT-based organized CRC screening. Neighborhood SES or small-area SES was more competent than individual SES to be employed to assess the association between SES and adherence. Race/ethnicity was probably an important confounding factor for the association. The disparity of adherence between the high SES and the low SES narrowed along with the development of interventions and the improvement of organized programs.