Trends in Mortality, Hospital Cost, and Length of Stay in Lung Cancer Patients with and without Iron Deficiency Anemia: Data from the Healthcare Cost and Utilization Project from 1999-2014

Background: Anemia is commonly encountered in all types of cancer patients, with iron deficiency anemia accounting for nearly half of the cases. In addition to impact on quality of life and morbidity, we suspected that IDA might also impact various metrics, such as hospital charges, length of stay, and inpatient mortality. We examined these parameters in patients with and without iron deficiency anemia who were admitted to the hospital with lung cancer between the years 1999 and 2014.

Methods: We analyzed data from the Healthcare Cost and Utilization Project's (HCUP) National Inpatient Sample, between 1999 and 2014 using the ICD-9 codes for lung cancer (162) in the primary diagnosis field. The subset of these numbers with IDA (280.9) listed as a secondary diagnosis were recorded to derive a prevalence of iron deficiency anemia within this cancer population. The prevalence of iron deficiency anemia, total hospital cost, length of stay (LOS), and inpatient mortality were then compared.

Results: A total of 475,289 (weighted N=2,338,746) admissions with a primary lung cancer diagnosis were identified from 1999-2014. 7,870 (weighted N= 38,659) of the lung cancer admissions were associated with iron deficiency anemia. Hospital charges were higher in patients with concomitant IDA, $50,109 (± 618) versus patients without anemia $43,907 (± 830) (p<0.0001). IDA was also associated with an increase in length of stay, 8.2 days as compared to 7.3 days (p=0.05). Inpatient mortality was found to be higher in patients with IDA as compared to those without IDA, 12.7% compared to 7.7% (p<0.0001).

Conclusions: With lung cancer composing roughly 13% of new cancer cases in 2017 we suspected that any potential impact of cancer-related complications hospital charges, length of stay, and mortality, may be a significant one. In particular, IDA is a commonly found complication in lung and other cancers. In patients admitted to the hospital with lung cancer we found significantly higher inpatient mortality and hospital charges in patients with IDA than in those without. Interestingly, increased length of stay was not significant, though there was demonstration of a trend. We hypothesize that early identification and treatment of IDA may have a beneficial impact on morbidity, cost and length of stay in the inpatient population.