Importance: To date, the diagnostic test completion rate and the time to diagnostic endoscopy or colonoscopy among adults with iron-deficiency anemia (IDA) and/or hematochezia have not been well characterized.
Objective: To evaluate the diagnostic test completion rate and the time to diagnostic testing among veterans younger than 50 years with IDA and/or hematochezia.
Design, setting, and participants: This cohort study was conducted within the Veterans Health Administration between October 1, 1999, and December 31, 2019, among US veterans aged 18 to 49 years from 2 separate cohorts: those with a diagnosis of IDA (n = 59 169) and those with a diagnosis of hematochezia (n = 189 185). Statistical analysis was conducted from August 2021 to August 2023.
Exposures: Diagnostic testing factors included age, sex, race and ethnicity, Veterans Health Administration geographic region, and hemoglobin test value (IDA cohort only).
Main outcomes and measures: Primary outcomes of diagnostic testing were (1) bidirectional endoscopy after diagnosis of IDA and (2) colonoscopy or sigmoidoscopy after diagnosis of hematochezia. The association between diagnostic testing factors and diagnostic test completion was examined using Poisson models.
Results: There were 59 169 veterans with a diagnosis of IDA (mean [SD] age, 40.7 [7.1] years; 30 502 men [51.6%]), 189 185 veterans with a diagnosis of hematochezia (mean [SD] age, 39.4 [7.6] years; 163 690 men [86.5%]), and 2287 veterans with IDA and hematochezia (mean [SD] age, 41.6 [6.9] years; 1856 men [81.2%]). The cumulative 2-year diagnostic workup completion rate was 22% (95% CI, 22%-22%) among veterans with IDA and 40% (95% CI, 40%-40%) among veterans with hematochezia. Veterans with IDA were mostly aged 40 to 49 years (37 719 [63.7%]) and disproportionately Black (24 480 [41.4%]). Women with IDA (rate ratio [RR], 0.42; 95% CI, 0.40-0.43) had a lower likelihood of diagnostic test completion compared with men with IDA. Black (RR, 0.65; 95% CI, 0.62-0.68) and Hispanic (RR, 0.88; 95% CI, 0.82-0.94) veterans with IDA were less likely to receive diagnostic testing compared with White veterans with IDA. Veterans with hematochezia were mostly White (105 341 [55.7%]). Among veterans with hematochezia, those aged 30 to 49 years were more likely to receive diagnostic testing than adults younger than 30 years of age (age 30-39 years: RR, 1.15; 95% CI, 1.12-1.18; age 40-49 years: RR, 1.36; 95% CI, 1.33-1.40). Hispanic veterans with hematochezia were less likely to receive diagnostic testing compared with White veterans with hematochezia (RR, 0.96; 95% CI, 0.93-0.98).
Conclusions and relevance: In the cohorts of veterans younger than 50 years with IDA and/or hematochezia, the diagnostic test completion rate was low. Follow-up was less likely among female, Black, and Hispanic veterans with IDA and Hispanic veterans with hematochezia. Optimizing timely follow-up across social and demographic groups may contribute to improving colorectal cancer outcomes and mitigate disparities.