Comparison of Universal Versus Age-Restricted Screening of Colorectal Tumors for Lynch Syndrome Using Mismatch Repair Immunohistochemistry: A Cohort Study.

Background: Guidelines recommend screening all patients with newly diagnosed colorectal cancer (CRC) for Lynch syndrome (LS). However, the efficiency of universal LS screening in elderly populations has not been well studied. Objective: To compare the performance of age-restricted and universal LS screening using reflex mismatch repair (MMR) immunohistochemistry (IHC) of CRC tumors. Design: Retrospective cohort study. Setting: A large, diverse, community-based health care system. Participants: 3891 persons with newly diagnosed CRC who had LS screening between 2011 and 2016. Measurements: Diagnostic yield of different LS screening strategies. Results: Sixty-three LS cases (diagnostic yield, 1.62%) were identified by universal screening, with only 5 (7.9%) detected after age 70 years and 1 (1.6%) detected after age 80 years. When all patients with CRC who had universal screening were used as the denominator, 58 LS cases (diagnostic yield, 1.49% [95% CI, 1.13% to 1.92%]) were identified in patients with CRC diagnosed at or before age 70 years, 60 LS cases (diagnostic yield, 1.54% [CI, 1.18% to 1.98%]) were identified in those with CRC diagnosed at or before age 75 years, and 62 LS cases (diagnostic yield, 1.59% [CI, 1.22% to 2.04%]) were identified in those with CRC diagnosed at or before age 80 years. Using 75 years as the upper age limit for screening missed 3 of 63 (4.8%) LS cases but resulted in 1053 (27.1%) fewer cases requiring tumor MMR IHC. Using 80 years as the upper age limit missed 1 of 63 (1.6%) LS cases and resulted in 668 (17.2%) fewer cases requiring tumor MMR IHC. Limitation: Persons who were eligible for but did not complete germline analysis were excluded from calculations of performance characteristics. Conclusion: The incremental diagnostic yield decreased substantially after age 70 to 75 years. Stopping reflex CRC screening for LS after age 80 years may be reasonable because of very low efficiency, particularly in resource-limited settings, but this merits further investigation. Studies evaluating the effect of diagnosing LS in elderly persons on their family members are needed. Primary Funding Source: Kaiser Permanente Northern California Division of Research.

Effect of Helicobacter pylori Treatment on Unexplained Iron Deficiency Anemia.

BACKGROUND: A large number of patients with iron deficiency anemia have no known cause of their anemia despite a full evaluation. Optimal management and follow-up for this issue is unclear. Results of previous studies have implicated Helicobacter pylori infection as a potential cause of iron deficiency anemia. OBJECTIVES: To investigate whether H pylori infection could be a cause of unexplained iron deficiency anemia. METHODS: All adult patients with both unexplained iron deficiency anemia and H pylori infection diagnosed between January 1, 2008 and April 30, 2015 were identified from Kaiser Permanente Northern California's electronic medical records database and were followed-up for up to 2 years. We employed bivariate statistics to analyze demographic and clinical characteristics between H pylori treatment groups (treated and untreated). Multivariable logistic regression was used to assess the odds of continued presence of anemia at follow-up. RESULTS: Of 508 subjects who fit our inclusion criteria, 408 subjects were treated for H pylori. The median initial level of hemoglobin was 10.5 g/dL and ferritin was 7.0 ng/mL. No difference existed in the continued presence of iron deficiency anemia at follow-up between those treated for H pylori and those not treated (24.3% vs 26.5%, p = 0.71). Both groups had improved levels of hemoglobin (25.4% mean increase in treated vs 27.5% mean increase in untreated) at follow-up. CONCLUSION: In contrast to the findings of previous studies, we found no evidence that H pylori is involved in causing iron deficiency anemia. Iron deficiency anemia resolved in most subjects regardless of H pylori treatment status.