PCPs misdiagnose about 1 in 4 cases of iron deficiency anemia

Many primary care physicians may be overusing laboratory tests for anemia screening, misinterpreting iron studies and underusing bidirectional endoscopy for new-onset iron deficiency anemia, according to a recent survey study.

The findings, published in JAMA Network Open, suggest that absent or conflicting guidelines for iron deficiency anemia (IDA) management may contribute to health care waste and medical error, Andrew J. Read, MD, MS, clinical lecturer in the department of internal medicine at the University of Michigan, Ann Arbor, and colleagues wrote.

To ascertain IDA testing and evaluation in the primary care setting, Read and colleagues administered a vignette-based survey to PCPs in August 2019. The researchers analyzed the frequency of anemia screening, interpretation of lab work, and data on the proportion of patients with new-onset IDA who were referred for GI tract evaluation.

“As iron deficiency anemia is a potential marker of GI tract cancers, thorough evaluation of cases of new onset iron deficiency anemia with upper endoscopy and colonoscopy is critical to prevent delays in diagnosis of GI cancers,” Read told Healio Primary Care.

Andrew J. Read

Overall, 325 physicians (55.4% men) completed the surveys. On average, respondents had 19.8 years of clinical experience.

Read and colleagues reported that physicians often screened patients for anemia (76.9%), “despite the absence of guidelines recommending routine anemia screening.”

When presented with laboratory values, most physicians (93%) correctly identified whether anemia was a result from iron deficiency or another cause in scenarios in which ferritin and transferrin saturation values were “concordantly low or normal,” the researchers wrote. However, diagnostic accuracy decreased in scenarios with discordant ferritin and transferrin saturation values. Physicians’ interpretations of iron studies were least accurate in scenarios with a “borderline low” ferritin level (40 ng/mL) and low transferrin saturation value (2%), in which 26.5% of respondents “incorrectly responded that this scenario did not indicate IDA,” Read and colleagues wrote.

Also, in cases of new-onset IDA, only 54.5% of physicians recommended an upper endoscopy and colonoscopy for women aged 65 years, and 55.1% of physicians recommended the same procedures for men aged 65 years, according to the researchers.

In other results, 48.9% of respondents reported that they would test all new asymptomatic patients for anemia by obtaining a complete blood count. PCPs who practiced primarily at an academic medical center were less likely to recommend obtaining a complete blood count (OR = 0.4; 95% CI, 0.18-0.86). However, more than 40% of all respondents said they would recommend repeat or periodic screening for anemia in patients aged 65 years.

When presented with a scenario of a 35-year-old pregnant woman, 85.5% of respondents who said they would care for the pregnant woman rather than refer her to an OB/GYN reported that they would screen her for anemia during the first trimester. According to the authors of a study previously published in Blood Advances, ferritin testing needs to be a routine part of maternal care and pregnancy health screening.

While obtaining a routine complete blood count in healthy adults is not recommended by current U.S. guidelines, it is nonetheless common, according to Read.

“If patients have new onset unexplained anemia, evaluating them for iron deficiency is important and, if present, GI endoscopic evaluation should be pursued,” he said.

References:

Read AJ, et al. JAMA Netw Open. 2021;doi:10.1001/jamanetworkopen.2021.27827.

Teichman J, et al. Blood Adv. 2021;doi:10.1182/bloodadvances.2021004352.