Risk factors for severe infections in secondary immunodeficiency: a retrospective US administrative claims study in patients with hematological malignancies

Figures & data

Figure 1. Number of infections (any and severe) in the 12-month pre-SID diagnosis period (mean) and the post-SID period (mean annualized). SD: standard deviation; SID: secondary immunodeficiency.

Figure 2. Percentage of patients who experienced a given number of any infections (A) or severe infections (B) in the 12-month pre-SID diagnosis period (absolute numbers) and post-SID periods (annualized numbers). *Absolute numbers of infections in the pre-SID period; annualized number of infections in the post-SID period (hence, a patient can have an annualized number of infections >0 and <1 infection during this period). SID: secondary immunodeficiency.

Figure 3. A ROC curve for infections pre-SID diagnosis as a predictor of risk of severe infections post-SID diagnosis. ROC: receiver operating characteristic; SID: secondary immunodeficiency.

Table 1. Multivariate Cox proportional hazards model evaluating characteristics associated with risk of severe infections post-SID diagnosis.

Variable	Hazard Ratio	95% Confidence Limits		p value
		Lower Limit	Upper Limit
Underlying condition (ref: CLL)
MM	1.042	0.891	1.219	0.608
NHL	0.972	0.839	1.125	0.700
>1 of the conditions	0.981	0.823	1.169	0.828
≥3 pre-SID diagnosis infections (vs < 3)	1.354	1.221	1.501	<0.0001
Post-SID diagnosis antibiotic use (yes vs no)^a	2.645	2.326	3.008	<0.0001
Post-SID diagnosis antiviral use (yes vs no)^a	0.913	0.792	1.053	0.213
Number of pre-SID diagnosis hospitalizations (ref:0)
1	3.118	2.714	3.582	<0.0001
2+	3.968	3.478	4.526	<0.0001
Baseline comorbidities^b (yes vs no)
COPD	1.177	1.039	1.332	0.010
Hypertension	1.110	1.011	1.219	0.029
Smoking	1.140	1.028	1.265	0.013
Baseline cancer treatment (yes vs no)
Rituximab	1.148	1.019	1.293	0.024

^aAssessed from diagnosis date until first occurring: severe infections or end of available follow-up.

^bIt was identified that baseline comorbidities of interest corresponded to diagnosis codes ICD-9-CM and/or ICD-10-CM; baseline comorbidities were then identified based on the presence of these diagnosis codes on medical claims during the 12-month baseline period.

CLL: chronic lymphocytic leukemia; COPD: chronic obstructive pulmonary disease; MM: multiple myeloma; NHL: non-Hodgkin lymphoma; SID: secondary immunodeficiency.

Data availability statement

The data that support the findings of this study are available from the corresponding author, SJ, upon reasonable request.