Multiple Listing in Lung Transplant Candidates

A Cohort Study

Joshua J. Mooney; Lingyao Yang; Haley Hedlin; Paul Mohabir; Gundeep S. Dhillon

Disclosures

American Journal of Transplantation. 2019;19(4):1098-1108. 

In This Article

Results

There were 43 578 patients ever listed for lung transplant in SRTR. A total of 20 848 subjects met the eligibility criteria for inclusion in our study and 2570 subjects are included in the matched dataset (Figure 1). Multiple listed candidates comprised 2.3% of US lung transplant waitlist candidates during the study period with a general increase in the number of annual multiple listing registrations from 2006 to 2014 (Figure 2). The characteristics of all SL and ML candidates are shown in Table 1. A greater proportion of ML candidates were female (63.2% ML vs 44.6% SL), required a preliminary antibody crossmatch (10.3% ML vs 5.9% SL), and had cystic fibrosis (24.3% ML vs 11.4% SL). ML candidates had a longer total time on the waitlist (median 282 days; IQR 86, 616) than SL candidates (median 90 days; IQR 25, 281). ML candidates were more likely to have received a college (44.7% ML vs 41.3% SL) or postcollege graduate degree (13.0% ML vs 8.0%) and have private insurance (64.6% ML vs 57.9% SL). The median difference (IQR) in LAS from initial listing to multiple listing was 0.9 (0, 4.0).

Figure 1.

STROBE diagram. The diagram displays the numbers of candidates meeting study inclusion and exclusion criteria and the number of candidates included in the matched dataset

Figure 2.

Annual number of multiple listing registrations. The figure displays the number of new multiple listing registrations within each calendar year from 2006 to 2014

Of ML candidates, 82.1% obtained their second transplant registration at a transplant center outside their initial OPO and 46.9% within a different OPTN region. 43.7% of ML candidates did so at a transplant center with a higher transplant rate with a median difference in transplant rate between the multiple listing center and initial listing center of -3.0 transplants per 100 waitlist years (IQR −25.0, 19.0). The proportion of ML candidates by each transplant center is shown in Figure 3. One-third (34.1%) of all multiple listing registrations occurred at one of five lung transplant centers. Of ML candidates who underwent lung transplant, 26% underwent transplant at their initial listing center and 74% at the center of multiple listing.

Figure 3.

Multiple listing registrations by transplant center. The figure demonstrates the distribution of all multiple listing registrations by lung transplant center. Each bar demonstrates the percentage of nationwide multiple listings that are registered within an individual transplant center

Of ML candidates, 32.4% obtained their second listing in an OPO with a higher transplant rate (median difference of 0.0 transplants per 100 waitlist years; IQR −16.0, 6.0) and 33.1% in an OPTN region with a higher transplant rate (median difference of 0.0 transplants per 100 waitlist years, IQR 0.0, 17.2). The proportion of ML candidates in each OPO and OPTN region are shown in Figures 4 and 5. Greater than 50% of all multiple listing registrations were within seven OPOs or within three OPTN regions.

Figure 4.

Multiple listing registrations by organ procurement organization. The figure demonstrates the distribution of all multiple listing registrations by organ procurement organization. Each bar demonstrates the percentage of nationwide multiple listings that are registered within an individual organ procurement organization

Figure 5.

Multiple listing registrations by Organ Procurement and Transplantation Network (OPTN) region. The figure demonstrates the distribution of all multiple listing registrations by OPTN region. Each bar demonstrates the percentage of nationwide multiple listings that are registered within an individual OPTN region

After multivariable adjustment, age (adjusted odds ratio [aOR] 0.98, 95% CI 0.97-0.99), cystic fibrosis (aOR 1.44, 95% CI 1.03-2.02), initial LAS (aOR 0.96, 95% CI 0.95-0.97), height (aOR 0.99, 95% CI 0.98-1.00), male gender (aOR 0.64, 95% CI 0.51-0.81), white race (aOR 1.38, 95% CI 1.03-1.86), college education (aOR 1.34, 95% CI 1.09-1.66), postcollege graduate education (aOR 2.64, 95% CI 1.98-3.52), and preliminary antibody crossmatch requirement (aOR 1.62, 95% CI 1.23-2.14) were associated with the likelihood of multiple listing (Figure 6). In a sensitivity analysis that added the initial listing OPTN region, the previously statistically significant variables except for white race remained significant and OPTN region 1 (aOR 2.44, 95% CI 1.67-3.57), region 5 (aOR 1.38, 95% CI 1.01-1.88), region 6 (aOR 0.26, 95% CI 0.10-0.66), and region 9 (aOR 1.56, 95% CI 1.03-2.36) were also independently associated with multiple listing when treating region 2 as the reference region. An additional sensitivity analysis that added an indicator for functional status did not modify the significance of the previously identified variables but did demonstrate an additional association of needing full assistance (as compared to no assistance) with a reduced likelihood of multiple listing (aOR 0.62, 95% CI 0.44-0.88).

Figure 6.

Candidate characteristics associated with multiple listing. The adjusted odds ratio for each variable included in a multivariable logistic regression model of multiple listing is displayed. Reference groups for categorical variables included chronic obstructive pulmonary disease for diagnosis group, A blood type for blood type, and high school education level or below for education level. The odds ratio for age is per 1 year, for LAS is per 1 point, and for income is per $1

The characteristics of matched SL and ML candidates included in the analysis of likelihood of transplant and waitlist mortality are shown in Table 2. Multiple listing was associated with a 2.7-fold increase in receiving a lung transplant (adjusted hazard ratio [aHR] 2.72, 95% CI 2.36-3.14). Multiple listing was not associated with waitlist mortality (aHR 1.02, 95% CI 0.70-1.48). Sensitivity analyses that additionally adjusted for functional status did not modify the relationship of multiple listing with the likelihood of lung transplant (aHR 2.71, 95% CI 2.34-3.13) or waitlist mortality (aHR 1.06, 95% CI 0.73-1.55). In an exploratory secondary analysis of a matched subset of 312 SL and 78 ML candidates in pairs where the ML candidate had a listing LAS ≥ 40, multiple listing increased the likelihood of lung transplant (aHR 1.98, 95% CI 1.36-2.89) but was not associated with waitlist mortality (aHR 0.59, 95% CI 0.18-1.91).

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