Travel Practices and Associated Risks in Adult Thoracic Transplant Recipients: A Monocentric Survey

Abstract

Background

Little is known regarding the travel practices of thoracic organ transplant recipients and their potential associated morbidity.

Methods

A questionnaire was distributed to thoracic organ transplant recipients to capture demographics, risk perception, knowledge regarding vaccination, history of travel outside metropolitan France, pre‐travel advice, health issues during travel outside Europe, and travel intentions in the following year. Comparisons were performed between travelers and non‐travelers through univariable then multivariable logistic regression.

Results

134 patients completed the survey (72% lung, 11% heart, and 17% heart–lung transplant recipients). Twenty‐four percent considered themselves at moderately to significantly increased risk of travel‐related health issues. Sixty‐two patients (47%) had traveled outside metropolitan France. Among 29 subjects who had traveled outside Europe, 22 had received pre‐travel advice. Among 62 respondents who had traveled outside metropolitan France, 6 (10%) experienced health issues (all outside Europe), which led to consultation in three cases and hospitalization in one case. Among 117 respondents, 68 (58%) intended to travel within the following year, and 57 (84%) to seek medical advice before departure, predominantly from their transplant physician. In multivariable analysis, being a lung transplant recipient and higher education level were associated with travel outside Europe. The time post‐transplantation was longer for all types of travel, when compared to non‐travelers.

Conclusions

Almost half of adult thoracic transplant recipients had traveled outside metropolitan France, 22% outside Europe, and 10% of travelers experienced health issues. The suboptimal preparation of these patients underlines the potential benefits of closer interaction between travel medicine specialists and transplant physicians.

Abbreviations

CF

cystic fibrosis

CNIL

Commission Nationale Informatique et Libertés

LMIC

low and middle‐income countries

SOT

solid organ transplant

1. Introduction

Solid organ transplantation (SOT) is a lifesaving procedure that has become a standard of care for organ failure in many countries. Recent years have seen an increase in global transplant activity, except for the temporary reduction of this activity due to COVID‐19 restrictions. It is estimated that in 2021, 144 302 organ transplants were performed worldwide. Among these, 8409 were heart transplants, and 6470 were lung transplants [1]. The median survival of thoracic transplant recipients has steadily improved over time [2, 3], thanks to improvements in surgical techniques, better perioperative management, availability of new immunosuppressive drugs, progress in the understanding and management of rejection, and improved anti‐infective strategies.

International travel has also been increasing worldwide: in 2019, it is estimated that 1.47 billion international trips were undertaken, compared to 0.96 billion in 2010; this figure has nevertheless transiently decreased as a result of the SARS‐CoV‐2 pandemic [4].

Consequently, it is expected that an increasing number of SOT recipients will undertake international travel in the future, for leisure or professional reasons.

Immunocompromised hosts such as SOT recipients represent a very specific population, and are more at‐risk while traveling internationally, as some travel‐associated infections, such as leishmaniasis or tuberculosis, can present with a more severe or protracted form [5]. Additionally, some travel‐related live attenuated vaccines, such as the yellow fever vaccine, are contra‐indicated in this population, and immunogenicity of vaccines is usually reduced. The management of immunosuppression and anti‐infectives can also be more challenging during international travel: for example, dehydration secondary to traveler's diarrhea can increase plasma levels of calcineurin inhibitors, increasing the risk of side effects; gastrointestinal infections can compromise intake or absorption of anti‐infectives; immunosuppressants can also significantly interact with anti‐infectives. Vaccine‐preventable infections such as influenza can be difficult to prevent in cases of travel to the southern hemisphere at a time when the updated version of the vaccine is not yet available in the northern hemisphere. Despite these elements, there is a limited amount of available data regarding travel practices of SOT recipients: four surveys have been conducted so far, in Canada, the United States, the Netherlands and Germany [6, 7, 8, 9]. The proportion of respondents who reported traveling varied from 27% to 95%, and 8% to 29% of travelers reported a clinical illness. Although these studies provided important information, two focused on one transplant type (one on kidney transplantation [9], one on heart transplantation [8]. Only two studies included lung transplant recipients (14 patients in one study [7], 25 in the other [6]. Moreover, travel habits are a product of many socioeconomic factors that vary greatly across countries; it may be inaccurate, in this case, to extrapolate data originating from North America or northern Europe to other settings. Finally, in this rapidly evolving field, all the available studies were conducted between 2001 and 2006.

To overcome these issues, we conducted a survey at a thoracic transplantation center in France to evaluate the number of trips undertaken, factors associated with such travel and potential associated morbidity in a population of adult lung, heart and heart–lung transplant recipients.

2. Patients and Methods

2.1. Patient Selection

All adult cardiac and lung transplant recipients, transplanted and followed at Marie Lannelongue Hospital, France (a referral center for transplantation in pulmonary hypertension), attending the transplant clinic between October 2015 and October 2018, were considered eligible, regardless of the time post‐transplant. Participation was voluntary and no financial compensation was granted to respondents. Pediatric patients and patients affected by cognitive impairment were excluded from the study. No specific travel‐related education program for transplant recipients was in place during the study period, nor was a specified protocol in case of international travel requesting systematic bloodwork or contact with the transplant team.

2.2. Survey Questionnaire

A paper questionnaire was distributed to patients in the waiting room of the transplant clinic, each distribution being accompanied by a written clear presentation of the objectives and questionnaire. It included an information note, and was then divided into five parts: (1) general patient information (transplant information, underlying disease, current medications, education level and occupation); (2) potential post‐transplant travel, destination and purpose; (3) in case of post‐transplant travel, the existence of pre‐travel advice and its nature; exposure to specific risks; vaccinations; (4) potential travel‐associated health issues in the past 5 years; and (5) intention to travel in the following year. Participants who had not been traveling post‐transplant were not required to fill parts 3 and 4 of the questionnaire.

2.3. Definitions

Low‐ and middle‐income countries (LMIC) were defined according to the World Bank report [10].

2.4. Statistics

Regarding descriptive statistics, qualitative variables were expressed as numbers and percentages; quantitative variables were expressed as mean or median, depending on the distribution. Comparisons between groups were made using Chi‐square or Fisher's exact test, as appropriate, for qualitative variables; and Student's t‐test or Mann–Whitney test, as appropriate, for quantitative variables. Following univariate analysis, a multivariable logistic regression was conducted to address factors potentially independently associated with travel activities. For this purpose, three dependent binary variables were created: having traveled or not, regardless of the destination; having traveled outside Europe or not; having traveled to LMIC or not. Values that were significantly associated with these three types of travel activities in univariate analyses were considered for the multivariable model, within the validity limits of such a model (summarized in Table S5). All tests were 2‐sided and a p value lower than 0.05 was considered significant. Analyses were conducted with R (version 4.2.2) and Rstudio software. Figures were prepared using Microsoft Excel and maps were made using mapchart.net.

2.5. Ethics

The study was registered at CNIL (Commission Nationale Informatique et Libertés, National Commission on Informatics and Liberties) under the number boR1358269s. Patients were informed at the study entry and gave their consent. Because no supplementary biological test was requested, no specific request was sent to the Ethical Committee. This study was conducted in accordance with the STROBE guidelines [11].

3. Results

3.1. Demographics

The general demographics of the 134 survey responders are presented in Table 1. Briefly, the mean age was 49 years, a majority of patients were women (59.7%), and most respondents were lung transplant recipients (n = 86, 71.7%). The majority (84%) of patients were born in metropolitan France and all of them resided in France. The main underlying disease for lung transplantation was pulmonary arterial hypertension, followed by interstitial lung disease. Regarding heart transplantation, congenital heart disease and idiopathic cardiomyopathy were the main indications. During the study period, 350 transplant recipients were actively followed at our center.

TABLE 1.

General demographic characteristics of 134 survey respondents.

Variable	N (%)
Age, years (mean, SD); n = 98	49.5 (28.4)
Gender, male (%), n = 134	54 (40.3)
Transplanted organ, n = 120
Heart	13 (10.8)
Lung	86 (71.7)
Heart–Lung	21 (17.5)
Time post‐transplant, months (mean, SD), n = 131	64 (38)
Country of birth, n = 131
France	110 (84)
Algeria	7 (5.3)
Tunisia	3 (2.3)
Madagascar	2 (1.5)
Othersa	8 (6.4)
Education level, n = 122
Primary school	47 (38.5)
Secondary school	33 (27.0)
Tertiary education	42 (34.4)
Employment status, n = 123
Professionally active	64 (52)
Retired	23 (18.7)
No current occupation	36 (29.3)
Underlying disease, n = 129
Pulmonary hypertension	70 (54.3)
Interstitial lung disease	23 (17.8)
Chronic Obstructive Pulmonary Disease	17 (13.2)
Other lung diseases	6 (4.7)
Congenital heart disease	4 (3.1)
Idiopathic cardiomyopathy	3 (2.3)
Other cardiomyopathies	6 (4.7)
Current immune suppression
Steroids, n = 131	94 (71.8)
Calcineurin inhibitors, n = 133	128 (96.2)
Mycophenolate, n = 131	91 (69.5)
Azathioprine, n = 131	18 (13.7)
mTOR inhibitors, n = 131	18 (13.7)
Comorbidities
Diabetes, n = 113	15 (13.3)
Liver disease, n = 114	1 (0.9)
Heart failure, n = 114	4 (3.5)
Rheumatic disease, n = 113	5 (4.4)

Abbreviations: mTOR, Mammalian target of rapamycin; SD, Standard deviation.

^aArgentina, Belgium, Comoros, Côte d'Ivoire, Spain, United States of America, Haiti, Morocco (one patient each). For each variable, the number of respondents who provided usable answers is indicated. Percentages are presented after exclusion of missing data.

3.2. Knowledge Regarding Vaccines and Travel‐Associated Risks

Out of 128 respondents, 81 (63%) indicated that they had received vaccines post‐transplantation (any vaccine, regardless of traveling activities). The details of patients’ knowledge regarding their vaccination status are given in Table 2. When interrogated about their perception of travel‐associated risks, 44 patients (38%) responded that being an organ transplant recipient did not increase their risk of travel‐related illness. The risk was considered mild, moderate and significant for 39%, 15%, and 9% of respondents, respectively.

TABLE 2.

Knowledge of respondents regarding their vaccination status.

Patient's awareness regarding vaccination status	N responding yes (%)
Post‐transplant vaccinationa, n = 128	81 (63.3)
Having received post‐transplant influenza vaccinationb, n = 116	61 (52.6)
Having received post‐transplant pneumococcal vaccinationb, n = 116	20 (17.2)
Having received post‐transplant DTP vaccinationb, n = 116	7 (6.0)
Having received post‐transplant hepatitis B vaccinationb, n = 116	3 (2.6)
Having received another post‐transplant vaccinationb, n = 116	5 (4.3)
Considers being up to date regarding yellow fever vaccineb, n = 75	9 (12.0)
Considers being up to date regarding DTP vaccineb, n = 93	48 (51.6)

Abbreviation: DTP, Diphtheria, tetanus, poliomyelitis.

^aRegardless of the type of vaccines, the number of injections and the timing post‐transplantation.

^bRegardless of the number of injections and the timing post‐transplantation. For each variable, the number of respondents that provided usable answers is indicated. Percentages are presented after exclusion of missing data.

3.3. Travel Activities

Out of 132 respondents, 62 patients (47%) reported travel activities outside France, having taken an average number of seven trips, regardless of the destination (1 to 5 trips: 35 patients; 6 to 10 trips: 9 patients; more than 10 trips: 7 patients; data missing for 11 patients). The distribution of destinations was as follows: Europe, n = 49 (89%); Africa, n = 20 (36%), North America, n = 11 (19%), Central and South America, n = 4 (7%), Asia, n = 9 (16%), Oceania, n = 1 (2%), overseas France, n = 4 (7%). For two respondents, the destinations were not indicated. The description of travel destinations is shown in Figure 1.

FIGURE 1.

Destinations of 62 thoracic transplant recipients reporting having traveled outside metropolitan France post‐transplantation. The color code is based on the number of trips reported, considering that several respondents reported traveling to multiple countries. Countries in gray: No travel activities reported.

3.4. Characteristics of the Most Recent Travel Outside Europe (Table S1)

Twenty‐nine patients reported travel outside Europe (median number of trips, 5; 24 patients reported traveling to a low and middle‐income country [LMIC]). The average duration of the most recent trip was 16 days, and the two main reasons were vacation and visiting friends and relatives (66.7% and 14.8%, respectively). Twenty‐two (75%) of respondents had sought medical advice prior to the trip, mostly from their transplant physician (n = 20, 91%; with participation of the family physician in half of the cases). In patients providing details on the nature of the advice, vaccines were discussed in 36% of cases, diarrhea in 14%, and sun exposure in 93% of cases. During the trip, only one patient experienced a medication shortage. Regarding specific and potentially at‐risk activities, eight patients reported hiking. Tattooing, casual sex, and caving were rare (one occurrence each, casual sex and caving being reported by the same patient). No patient engaged in diving. One patient reported having traveled in a malaria‐endemic area, but did not take antimalarial prophylaxis.

3.5. Travel‐Associated Health Issues (Table S2)

Out of 62 travelers, six patients experienced health issues. In two cases, the country was not indicated, and in the four remaining cases, illness occurred in Algeria, Brazil, Madagascar and Tunisia (one patient each). During the trip, three patients required a medical consultation, one of which was admitted to a hospital. Two patients underwent medical repatriation. The initial diagnosis (made on‐site) was indicated in five patients (one upper respiratory tract infection, one lower respiratory tract infection, two non‐specific respiratory and gastrointestinal symptoms, and one urinary tract infection). Upon return, all but one patient sought medical advice, and three patients required hospital admission (including the two that had undergone repatriation). Rejection was diagnosed in one patient, in association with Aspergillus infection (this patient had been practicing caving). In another patient, a Pseudomonas and Corynebacterium respiratory infection was diagnosed. Of note, two of these six patients also reported a motor vehicle accident during their travel. A univariate comparison of travelers who developed health issues with those who did not only identified more patients who were born outside France among ill travelers (66.7% vs. 20.6%, p = 0.039; Table S3).

3.6. Factors Associated with Travel Activities (Table S4)

Univariable and multivariable comparisons were undertaken to assess factors associated with a history of travel (any destination, n = 62; travel outside Europe, n = 29; and travel to LMIC, n = 24).

Regarding global travel activity (any trip outside France; Table S4a), univariable logistic regression identified the following factors as being associated with travel: higher education (odds ratio [OR] 2.16, p = 0.048), being professionally active (OR 2.63, p = 0.027) and time post‐transplantation (expressed in years; OR 1.09, p = 0.002). In multivariable analysis, only time post‐transplantation was found to be associated with travel (OR 1.09, 95% confidence interval (95% CI) 1.009–1.191), p value 0.037).

Regarding travel outside Europe (Table S4b), lung transplant recipients were found to have traveled more (81% of travelers vs. 48.3% of non‐travelers, p = 0.015); as were patients born outside France (33.3% of travelers vs. 11.5% of non‐travelers, p = 0.009) and patients with a higher level of education (tertiary education: 59.3% of travelers vs. 29.2% of non‐travelers, p = 0.006). Travelers were less likely to receive steroids (53.6% vs. 78.1%, p = 0.012). In multivariable analysis, only higher education remained associated with travel (OR 3.8, 95% CI 1.28–12.25, p = 0.019).

Regarding travel to low and middle‐income countries (Table S4c), in univariable analysis, higher education (63.6% vs. 29.8%, OR 4.12 (95% CI 1.59–11.4, p = 0.004) and being born outside France (34.8% vs. 12%, OR 3.91 (95% CI 1.34–11.2, p = 0.011), were also associated with travel, as well as time post‐transplant (OR 1.09, 95% CI 1.03–1.16, p = 0.005). Lung transplant recipients were less likely to travel (OR 0.22 (95% CI 0.06–0.84, p = 0.022). Multivariable analysis again identified time post‐transplant (OR 1.1, 95% CI 1.03–1.19, p = 0.007) and higher education (OR = 4.03, 95% CI 1.36–13, p = 0.014) as being associated with travel.

Of note, the self‐assessment regarding travel‐associated risks did not differ between travelers and non‐travelers, regardless of the type of travel considered (Europe vs. outside Europe or LMIC).

3.7. Future Travel Intentions

Among 117 respondents, 68 (58.1%) expressed an intention to travel within the following year. In 10 patients, the destination was not specified. For the 58 remaining patients, travel destinations are indicated in Figure 2. Fifty‐seven (83.8%) patients were intending to seek medical advice before traveling. The intended healthcare professional was: the transplant physician in 35 patients (51.5%), the transplant physician and the family physician in 14 (20.6%), the transplant physician and a travel medicine specialist in 5 (7.4%), the family physician in 1, a travel medicine specialist in 1, and all these professionals in 1 (1.5%). When comparing past history of travel and travel intentions, 39/56 (69.6%) of respondents with a past history of travel also intended to travel in the following year, compared with 29/59 (49.2%) of respondents without a history of post‐transplant travel. This difference was statistically significant (p = 0.025, Chi‐squared test).

FIGURE 2.

Intention to travel within the following year in 58 thoracic transplant recipients. Countries in gray: No travel intentions reported.

4. Discussion

International travel patterns of thoracic, especially lung transplant recipients, have been scarcely studied so far. This study adds to the limited body of knowledge available in this field, providing recent data in a country that had not yet been studied from this perspective.

Approximately half of the respondents had undertaken trips outside mainland France after transplantation. While a great majority (89%) had traveled to Europe, an expected finding in a European country, about half of these patients had also traveled outside Europe, and an important proportion of these travels (n = 24, 39%) took place in LMIC where the risk of infection can be more significant. In comparison, 36% of respondents in the Canadian study, and 27% of respondents in the American study had traveled outside North America [6, 7]. Our findings are more in line with the Dutch data, in which 43% of renal transplant recipients had traveled outside Western Europe [9].

Expectedly, travel destinations differ between our study and North American studies, with more French patients traveling within Europe and to Africa (mainly North Africa), and fewer patients traveling to the Caribbean and Central America. Social and demographic differences between residents of France and North Americans, and immigration patterns partly due to historical links, very likely account for part of these differences. Destinations in our study were quite close to the patterns reported by Dutch respondents, and overall mirror the travel destinations of the French general population [12].

There is a limited amount of data regarding the perception of SOT recipients of their travel‐associated risks; in our study, more than one‐third of respondents did not consider themselves at increased risk of health issues while traveling. Whereas the relatively low travel‐associated morbidity observed in our study is a rather reassuring factor, SOT recipients should be reminded that caution is of importance while traveling, as usually benign health issues such as strongyloidiasis can rapidly escalate to serious illness in SOT recipients [13]. Interestingly, self‐assessment of risks associated with travel did not differ across travelers and non‐travelers, regardless of the destination.

The rate of respondents who sought medical advice before traveling was high, especially in comparison with previously reported works in North America [7]. It is noteworthy, however, that SOT recipients frequently consulted their transplant physician, but very rarely travel medicine specialists. The reasons for this preference were not specifically asked in the questionnaire, and remain subject to hypothesis; the privileged relationship between SOT recipients and their physicians, given the severity of the initial disease, the complexity of care, and the necessity for frequent clinic visits, is likely a causal factor. Additionally, few patients traveled to areas where the yellow fever vaccine is mandatory, and this vaccination is an acknowledged reason for visiting a travel medicine clinic.

Regarding preparation for travel, a relatively low proportion of high‐risk activities was observed. However, vaccine knowledge was suboptimal, which emphasizes the difficulty of maintaining self‐awareness on multiple health‐related topics in transplant recipients. Only one patient reported having traveled to a malaria‐endemic area, even if the list of destinations comprised more than one malaria‐endemic country, leaving room for improvement of travel preparation. Regardless of malaria, some respondents did travel to areas where mosquito‐transmitted diseases are endemic [14], but only a small proportion of them reported using bed nets and repellents.

The proportion of health issues encountered by thoracic transplant recipients during travel was low (9.7% of travelers), which is in line with figures reported from the USA, and less than what was observed in Canada (17%), the Netherlands (24%) and Germany (16%). It should be noted, however, that if considering only traveling outside Europe, 6 out of 29 (21%) patients experienced health‐related issues. These elements seem to indicate that, if carefully prepared, international travel in SOT patients carries a risk that appears comparable to the general population. It is noteworthy that although 21% of our population traveled to the tropics (essentially in Africa and South America), no infection classically associated with this type of travel was reported. Only one episode of rejection was observed, which is not significantly different from what was expected in this population. Finally, only one patient was admitted overseas (the country was not specified). This information remains important, however, as this can be a risk factor for the acquisition of multi‐drug resistant organisms [15].

Some demographic factors were found to be associated to travel activities: higher education was consistently associated with all travels outside Europe, probably reflecting increased financial means that ease international travel. Heart–lung transplant recipients, interestingly, did seem to have traveled more than other thoracic transplant recipients. This fact may be related with an overall good prognosis of heart–lung transplantation (in the population that survives beyond 1 year post‐transplant [3]). Being born outside France was also associated with travel outside Europe, presumably to visit friends and relatives. This fact was consistently observed in previous studies [6, 7, 8, 9]. In all types of travel, time post‐transplant was positively associated with travel activities, an expected finding as the very close medical follow‐up during the first year post‐transplantation leads almost all transplant teams to discourage international travel in the first year. In our cohort, out of 62 patients who traveled outside France, 5 (8%) did it during the first year post‐transplant. All these five patients traveled within Europe and none reported travel‐associated health issues. More health‐related issues during travel were noted among patients who were born outside France, a fact that was already underlined in the American study [7].

This study has limitations. For logistical reasons, we were unable to screen the whole transplant cohort, reducing the amount of information and potentially introducing respondent bias. A similar issue precluded a thorough investigation of missing data through patient recall. Our center has specific expertise in lung or heart–lung transplantation for pulmonary hypertension; conversely, lung transplantation for cystic fibrosis (CF) in the Paris area is performed in another center. We were, therefore, not able to capture the travel patterns of the CF population, which is usually younger at the time of transplantation. This study was monocentric, hence limiting the generalizability of our findings. The relatively limited number of patients reduced the amount of variables that could be entered into multivariable models. This study was based on questionnaires, and inconsistencies due to reporting bias and patient memory could not be avoided: for instance, the post‐transplant vaccination rates reported by patients are likely underestimates, as only 53% of patients responded having received anti‐influenza vaccines and 17% anti pneumococcal vaccines, although these vaccines are routinely offered to all transplant recipients beyond the first year post‐transplantation. Moreover, in the case of the influenza vaccine, the number of vaccines that were received post‐transplant and the date of the last injection do not perfectly depict the immunization status. A similar issue limited the amount of detail regarding the travel‐related health issues that our patients encountered. We did not compare predictors of travel activity in our transplant cohort with predictors found in other immunocompromised hosts, as done in the Canadian study [6].

In conclusion, a significant proportion of thoracic transplant recipients reported traveling post‐transplantation, including travels beyond Europe, with overall limited associated morbidity. However, travel preparation, especially vaccinations, counseling and repellent usage for the prevention of vector‐borne diseases, could be improved. The transplant physicians are the primary contacts of these patients regarding travel‐related health issues and counseling. Emphasis should be put on the potential benefits of dedicated travel medicine clinic visits for SOT recipients, and on maintaining transplant physician's awareness of travel‐related health issues. If carefully prepared, international travel of thoracic transplant recipients (including those in LMIC, with the usual precautions associated with the risk of yellow fever) should not be discouraged.

Author Contributions

Benoît Henry, Paul‐Henri Consigny, Pierre Frange, Fanny Lanternier, and Olivier Lortholary designed the study. Benoît Henry collected data, performed analysis, and wrote the initial draft of the manuscript with Olivier Lortholary. Aurélie Garraffo, Ngoc‐Tram To, and Jérôme Le Pavec collected data. Claire Rouzaud, Pierre Buffet, Benoît Pilmis, Elie Fadel, and Shahid Husain revised the manuscript for important intellectual content. All authors critically revised the contents of the manuscript.

Conflicts of Interest

The authors declare no conflicts of interest.

Supporting information

Supplemental Table S1: characteristics of the most recent trip conducted outside Europe in 29 travellers. For each variable, the number of respondents who provided usable answers is indicated. Percentages are calculated after accounting for missing data. Malaria‐endemic area is reported as assessed by the patient. GP: general practitioner. SD: standard deviation.

Supplemental table S2: patients reporting health‐related issues during travel. NA: data not available; GI: gastrointestinal; LRTI: lower respiratory tract infection; URTI: upper respiratory tract infection; UTI: urinary tract infection.

Supplemental Table S3: comparison of travellers who developed health issues with travellers that did not. SD: standard deviation; PAH: pulmonary arterial hypertension; ILD: interstitial lung disease; COPD: chronic obstructive pulmonary disease; mTOR: mammalian target of rapamycin. Comparisons were made through Chi‐squared and Fisher's exact test, for categorical variables; and with Student's t test for quantitative variables. #: at the time of filling out the questionnaire.*: refers to a perception of an increased risk of travel related issue associated with transplantation.

Supplemental Table S4a: factors associated with travel activities. Comparisons were made between travellers (any destination outside metropolitan France) and non‐travellers. # : at the time of filling out the questionnaire. *: refers to a perception of an increased risk of travel related issue associated with transplantation. OR: odds‐ratio; aOR: adjusted odds ratio; PAH: pulmonary arterial hypertension; ILD: interstitial lung disease; COPD: chronic obstructive pulmonary disease; mTOR: mammalian target of rapamycin. Quantitative data are expressed as median (IQR).

Supplemental Table S4b: factors associated with travel activities outside Europe. Comparisons were made between travellers (any destination outside Europe) and patients not undertaking extra‐European travels. # : at the time of filling out the questionnaire. *: refers to a perception of an increased risk of travel related issue associated with transplantation. OR: odds ratio; PAH: pulmonary arterial hypertension; ILD: interstitial lung disease; COPD: chronic obstructive pulmonary disease; mTOR: mammalian target of rapamycin. Quantitative data are expressed as median (IQR).

Supplemental Table S4c: factors associated with travel activities to low and middle‐income countries (LMIC). Comparisons were made between travellers to LMIC and patients not undertaking travels to LMIC. # : at the time of filling out the questionnaire. *: refers to a perception of an increased risk of travel related issue associated with transplantation. OR: odds ratio; aOR: adjusted odds ratio; PAH: pulmonary arterial hypertension; ILD: interstitial lung disease; COPD: chronic obstructive pulmonary disease; mTOR: mammalian target of rapamycin. Quantitative data are expressed as median (IQR).

Supplemental Table S5: analysis plan of the factors associated with travel. The three outcomes (i.e., type of travel) are indicated on the second line, as well as the variables included in the univariable and multivariable analyses, which are highlighted in green. LMIC: low and middle‐income country

Henry B., Garraffo A., Consigny P.‐H., et al. “Travel Practices and Associated Risks in Adult Thoracic Transplant Recipients: A Monocentric Survey.” Clinical Transplantation 39, no. 8 (2025): 39, e70206. 10.1111/ctr.70206

Data Availability Statement

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