OBJECTIVES:

To assess the burden of severe infections in patients with Primary Immunodeficiency (PI) diseases.

METHODS: The 2016 National Inpatient Sample (NIS) data set from the Healthcare Cost and Utilization Project was utilized in order to analyze hospital admission records for patients with PI. All severe infections were coded based on a targeted review of the literature. Two cohorts of patients were designed: PI with severe infection and w/o severe infection. Thirty comorbidities were assessed using Elixhauser scoring. Multivariate logistic regression was conducted to assess predictor variables for LOS and costs.

RESULTS:

In 2016, there were an estimated 114,100 hospitalizations with a diagnosis of PI, 44% with severe infections and 56% without severe infections. Demographically two cohorts are similar in terms of age, gender, race and insurance (53.73 [SD 23.02] vs 48.03 [SD 25.3] years old; Male 49% vs 46%, Medicare 49% vs 42%, White 75% vs 71%, Comorbidity score 3.9 vs 3.5, with vs without severe infections respectively). The hospital length of stay was longer in patients with severe infections (Mean 9.97 vs 8.01, p<0.05, Median 6 vs 4 days). The mean hospital charges in PI with severe infections vs without groups were $122,739 and $103,859, p<0.05, respectively. The mortality rate was significantly higher in the severe group 6.77% vs 2.09%, p<0.05. Two most common infections were pneumonia (J189) and Enterocolitis due to Clostridium difficile (A047). The top non-PI ICD-10 code in the severe infection group was sepsis, while in the non-infection group it was Encounter for chemotherapy.

CONCLUSIONS: Analysis of hospital records shows primary Immunodeficiency patients with severe infections incur significant costs, high morbidity and mortality.