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Published on: November 10, 2023
Impact of Invasive Mold Infection-Coded Diagnoses on Utilization, Costs, and Mortality After Lung Transplantation
Kelly M Pennington1, Herb Heien2, Hemang Yadav1
1Division of Pulmonary and Critical Care Medicine, Department of Medicine, Mayo Clinic, Rochester, MN; William J. von Liebig Center for Transplantation and Clinical Regeneration, Mayo Clinic, Rochester, MN.
Background:
Lung transplant recipients (LTRs) are highly susceptible to invasive mold infections (IMIs). In clinical practice, diagnostic codes for IMI serve as claims-based markers of suspected infection that often prompt antifungal therapy, but their real-world clinical and economic impact remains incompletely defined.
Research Question:
Among LTRs, are IMI-coded diagnoses associated with increased health care utilization, costs, and mortality?
Study Design And Methods:
We conducted a retrospective cohort study using the OptumLabs Data Warehouse (2005-2023). Adult LTRs were identified by procedure codes and followed from transplant until disenrollment, death, or December 2023. IMIs were defined by International Classification of Diseases, Ninth Revision/International Statistical Classification of Diseases and Related Health Problems, 10th Revision codes. Risk factors were assessed using multivariable logistic regression. A 1:2 matched cohort (age, sex, and transplant length of stay) evaluated health care utilization, costs, and mortality. Utilization and costs were calculated per patient-month (PPM) and stratified by payer. Mortality was assessed using Cox models.
Results:
Among 1,120 eligible LTRs, 343 (30.6%; 95% CI, 27.9%-33.4%) had an IMI-coded diagnosis, most commonly aspergillosis (88%). Male sex (OR, 1.52; 95% CI, 1.16-1.99) and cystic fibrosis (OR, 1.93; 95% CI, 1.14-3.28) were independently associated with IMI coding, whereas higher comorbidity burden was associated with lower odds (OR, 0.65; 95% CI, 0.43-0.98). In the matched cohort (IMI: n = 243; non-IMI: n = 486), IMI coding was associated with greater emergency department use (0.13 vs 0.10 visits/PPM; P = .018) and longer inpatient stay (3.28 vs 2.23 days/PPM; P = .031). Cost patterns diverged: commercially insured recipients with IMI-coded diagnoses had lower pharmacy costs ($3,416 vs $4,504/PPM; P = .006), whereas Medicare Advantage recipients incurred significantly higher inpatient, medical, and overall costs. IMI coding was associated with nearly 2-fold higher mortality (hazard ratio, 1.83; 95% CI, 1.33-2.51; P < .001).
Interpretation:
Our results show that IMI-coded diagnoses are common after lung transplant and are associated with greater acute care utilization, higher costs among Medicare Advantage recipients, and increased mortality. These findings underscore the clinical and economic burden of suspected mold infections in LTRs and highlight the need for integrated claims and clinical data to refine risk reduction strategies.
Insights
Invasive mold infections (IMIs) are common in lung transplant recipients (LTRs) and linked to increased healthcare use and mortality. Claims data reveal significant clinical and economic impacts, emphasizing the need for better prevention strategies.
Area of Science:
- Medical research
- Transplant surgery
- Infectious diseases
Background:
- Lung transplant recipients (LTRs) face a high risk of invasive mold infections (IMIs).
- Diagnostic codes for IMIs are used as markers for suspected infections and to guide antifungal therapy.
- The real-world clinical and economic consequences of IMI-coded diagnoses in LTRs are not fully understood.
Purpose of the Study:
- To determine if IMI-coded diagnoses in LTRs are associated with increased healthcare utilization.
- To assess the association between IMI-coded diagnoses and healthcare costs in LTRs.
- To evaluate the impact of IMI-coded diagnoses on mortality rates in LTRs.
Main Methods:
- Retrospective cohort study utilizing the OptumLabs® Data Warehouse (2005-2023).
- Adult LTRs identified by procedure codes, followed from transplant; IMIs defined by ICD-9/10 codes.
- A 1:2 matched cohort compared healthcare utilization, costs, and mortality, with Cox models for mortality assessment.
Main Results:
- 30.6% of 1,120 LTRs had an IMI-coded diagnosis, most commonly aspergillosis.
- IMI coding correlated with increased emergency department visits and longer inpatient stays.
- IMI coding was linked to nearly double the mortality rate (HR 1.83, p<0.001) and varied cost impacts by insurance type.
Conclusions:
- IMI-coded diagnoses are prevalent in LTRs and associated with elevated acute care utilization.
- Higher healthcare costs were observed in Medicare Advantage recipients with IMI codes, while pharmacy costs were lower for commercially insured patients.
- The findings highlight the substantial clinical and economic burden of suspected mold infections in LTRs, necessitating improved prevention strategies.
