Inpatient folate testing at an academic cancer center: single-year experience

The value of testing for folate deficiency has been scrutinized recently given low prevalence of deficiency with widespread dietary fortification. Numerous studies have shown folate testing to be low yield overall. However, the value of such testing in the inpatient cancer population has not been defined.

We queried all folate tests performed during 2017 at our center on admitted cancer patients. We used diagnosis codes and manual chart review to assess risk factors for folate deficiency. Descriptive statistics were used to summarize characteristics of patients undergoing folate testing, the frequency of vitamin B12 co-testing, and repeat folate testing. Fisher's exact test was used to compare the proportion of deficient vs. not deficient tests based on the presence of risk factors. A Cox proportional hazards model was fit to examine the association between folate deficiency and survival.

In total, 937 patients had 1065 tests performed during 2017. Among all tests, 7.0% indicated folate deficiency. In patients who underwent two folate tests in a single hospitalization, 89% were deficient neither instance. Risk factors for folate deficiency were equally common in instances with deficient compared with replete testing (25.3 vs. 20.4%, P = 0.334). Folate deficiency was associated with higher risk for death (HR 1.49, 95% CI 1.10-2.03, P = 0.01).

Folate deficiency was present in 7% of hospitalized cancer patients and associated with shorter overall survival. Repeat testing in the same patient over time was low yield. Traditional risk factors for folate deficiency do not appear to apply in this patient population.