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Author Spotlight: Investigating the Key Factors of Obliterative Bronchiolitis After Lung Transplantation
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, Tenth 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.
