Immunodeficiencies Push Readmissions in Malignant Tumor Patients: A Retrospective Cohort Study Based on the Nationwide Readmission Database.

To identify whether the presence or absence of IDDs was associated with readmission, we identified 603,831 patients with malignancies at their time of readmission in which 0.8% had IDDs and in which readmission occurred in 47.3%. Compared with NOIDDs, patients with IDDs had a higher risk of 30-day (hazard ratio (HR) of 1.32; 95% CI of 1.25-1.40), 90-day (HR of 1.27; 95% CI of 1.21-1.34) and 180-day readmission (HR of 1.28; 95% CI of 1.22-1.35). More than one third (37.9%) of patients with IDDs had readmissions that occurred within 30 days and most (82.4%) of them were UPRs. An IDD was an independent risk factor for readmission in patients with colorectal cancer (HR of 1.32; 95% CI of 1.01-1.72), lung cancer (HR of 1.23; 95% CI of 1.02-1.48), non-Hodgkin's lymphoma (NHL) (HR of 1.16; 95% CI of 1.04-1.28), prostate cancer (HR of 1.45; 95% CI of 1.07-1.96) or stomach cancer (HR of 2.34; 95% CI of 1.33-4.14). Anemia (44.2%), bacterial infections (28.6%) and pneumonia (13.9%) were the 30-day UPR causes in these populations. (4) Conclusions: IDDs were independently associated with higher readmission risks for some malignant tumors. Strategies should be considered to prevent the causes of readmission as a post discharge plan.