International tourist arrivals were estimated to reach 1 billion for the first time in 2012, with nearly half of all traveler arrivals in emerging economies. In 2011, 46% of individuals traveling internationally by air from the United States were visiting friends and relatives (VFR) travelers. Although the definition of VFR travelers varies throughout the literature, this term generally refers to immigrants currently residing in high-income countries returning to their homelands for a temporary visit, particularly when there is a gradient of epidemiologic risk between home and destination.
VFR travelers are generally considered to have higher travel-related health risks than tourists and business travelers. They typically have longer durations of travel, have more intimate contact with the host population, and travel to regions of the world with higher prevalence of communicable disease. They generally live and share meals with local hosts, with potentially greater exposure to unsafe food, water, and vector-borne diseases. VFR travelers have been consistently found to experience an increased burden of travel-related infectious diseases including malaria, viral hepatitis, typhoid fever, and sexually transmitted infections relative to tourists and business travelers.[4-10] Unfortunately, VFR travelers may underestimate their travel-associated health risks and may be less likely to seek pre-travel health advice or be appropriately vaccinated prior to travel.[4-7, 9, 10]
While the available literature demonstrates that VFR travelers have increased risk of travel-related infectious diseases relative to other travelers, little is known about the impact of VFR travel on chronic disease. Pre-travel health consultations often emphasize diarrhea prevention and treatment, vaccine-preventable diseases, and malaria prophylaxis. [8, 11-20] However, epidemiologic evidence suggests that travelers are far more likely to die from the same illnesses, complications, and acute events as they would at home, with cardiovascular disease accounting for the greatest proportion of all deaths during travel. One study of US travelers found that 49% of all deaths were due to cardiovascular events, much more than deaths due to accidents and infectious causes combined. Others have described unique challenges to chronic disease management associated with travel.[22-28] However, it is unclear if management of chronic medical conditions might also be impacted by VFR travel. It is anticipated that VFR travelers may experience poorer control of cardiovascular risk factors such as blood pressure, blood glucose, and lipid profile during their trips. In addition, serum levels of drugs with a narrow therapeutic window, such as warfarin, may be inadequately monitored, leading to increased risk of complications. The purpose of this study was to conduct a retrospective review to investigate the impact of VFR travel on health with a particular focus on markers of chronic disease management: hemoglobin A1c, low density lipoprotein (LDL), systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), serum creatinine (SCr), and international normalized ratio (INR).
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This investigation was approved by the Institutional Review Board of the University of Washington. All subjects in the study receive primary care services at a clinic serving adult, first-generation immigrants and refugees residing in King County, Washington. The clinic is associated with an academic medical center and visits were conducted by attending physician, medicine resident, physician's assistant, or clinical pharmacist. All patient visits were conducted face-to-face with the assistance of a professional interpreter owing to the limited English proficiency of the study patient population. Travel health services are routinely offered in the clinic and two of the attending physicians have specific training in travel medicine.
A retrospective chart review was performed on patients engaged in VFR travel between January 1, 2003 and December 31, 2010. Candidates for the study were identified by searching the electronic medical record for clinic notes in which travel was identified as the primary reason for the visit. Additional candidates were identified by reviewing the clinic's pharmacy dispensing records for patients who received the drug doxycycline. This strategy was chosen because virtually all of the clinic's patients who travel to malaria-endemic regions use doxycycline for malaria prophylaxis, as it represents the most affordable choice for those with limited incomes traveling for prolonged time periods in chloroquine-resistant areas. Inclusion criteria for the study included age ≥18, travel ≥21 days to a low-income country, documentation of a travel health counseling visit within the 6-month time period before the beginning of travel, and at least one additional visit within 6 months of return from travel. For patients who had more than one episode of travel, only the most recent travel encounter was included. Additionally, patients needed to have one or more of the following medical conditions at baseline in order to be included: diabetes, hyperlipidemia, hypertension, obesity, renal insufficiency, or a condition requiring chronic anticoagulation.
Study patients' records were reviewed to determine all chronic medical conditions at baseline, topics covered during the pre-travel visit, and any self-reported health problems or nonadherence to medications that occurred during travel. For the purposes of this investigation, medication nonadherence is defined as a patient stopping or running out of one or more medications during the travel period. In addition, the following markers of chronic disease management were compared before and after travel using a two-sided paired t-test: hemoglobin A1c, LDL, SBP, DBP, BMI, SCr, and INR.
A linear regression analysis was performed to identify predictors of medication nonadherence, including the following covariates: patient age, the number of medications, travel destination, duration of travel, and whether the patient received counseling on how to obtain medications to cover the duration of travel. A second linear regression was performed to identify factors associated with having a problem related to chronic conditions during travel, including the following covariates: patient age, travel destination, duration of travel, number of medications, documented nonadherence to medications, and whether or not the patient received counseling on chronic disease management during the pre-travel visit.
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A total of 110 patients were included in our analysis (Figure 1). Patient demographics are summarized in Table 1. All patients traveled either to Asia (N = 62) or Africa (N = 48), and the median duration of travel was 59 days (range 21–303). Languages spoken are summarized in Table 1 and are representative of both country of origin and travel destinations in Asia and Africa. Key elements of pre-travel preparations are described in Table 2. A total of 433 travel-related counseling points were documented in the medical record, averaging 4 counseling points per patient. Of these, 71% (N = 309) of all travel topics discussed were related to infectious disease prevention. Chronic disease and safety-related counseling topics comprised 16% (N = 69) and 13% (N = 55) of total health topics discussed at pre-travel visits, respectively. Table 2 further describes the percent of patients that received at least one piece of travel counseling advice in specific topic areas including: infectious disease, chronic disease, and safety.
Table 1. Patient demographics
| ||Median (range)|
|Year of immigration||1995 (1975–2008)|
|Primary languagea|| |
| Cambodian (Khmer)||25%|
|Chronic conditionsb|| |
| Renal insufficiency||12%|
| Chronic anticoagulation||3%|
|Additional baseline chronic conditions|| |
| Chronic pain/neuropathy||31%|
| Coronary disease/heart failure||17%|
| Asthma/chronic obstructive pulmonary disease||13%|
| Allergic rhinitis||12%|
| Nondiarrheal gastrointestinal disorders||11%|
| Post-traumatic stress disorder||10%|
| Thyroid disorder||7%|
| Benign prostatic hypertrophy/urinary incontinence||7%|
| Chronic skin conditions||5%|
| Chronic hepatitis||5%|
Table 2. Details of the pre-travel health visits
| ||Median (range)|
|Description of visits|| |
| Number of pre-travel visits||1 (1–4)|
| Duration of pre-travel visit(s) (minutes)||30 (5–100)|
| Days between pre-travel visit and travel||7 (1–120)|
| Days between travel and post-travel visit||23 (1–129)|
| ||Percent (N = 110)|
|Immunizations prescribeda|| |
| Patients provided ≥1 vaccine(s)||84%|
| Routine vaccine||63%|
| Travel vaccine||37%|
|Travel topics discussedb|| |
| Infectious disease||78%|
| Malaria prevention||61%|
| Water safety||58%|
| Food safety||56%|
| Diarrhea prevention||46%|
| Walking barefoot||7%|
| Chronic disease||44%|
| Purchase of medications||40%|
| Chronic disease safety||33%|
| General safety||20%|
| Caution around animals||16%|
| Deep vein thrombosis prevention||17%|
| Travel insurance||5%|
Sixty-three patients (57%) reported one or more health problems while traveling; 10 of these patients were sick enough that they sought care from a health care provider while abroad. Thirty-five patients (32% of travelers) experienced a health problem related to one or more chronic conditions diagnosed prior to travel (Table 3). Thirty patients had a problem related to one chronic condition and five patients experienced problems related to two chronic conditions. The most commonly identified health problems were related to diabetes management, worsening of reflux or other chronic gastrointestinal complaints, difficulties with blood pressure control, exacerbation of mental health issues, and worsening of chronic pain complaints. Two patients required inpatient admission after return to the United States, one patient presented with a congestive heart failure exacerbation and the other with new-onset atrial fibrillation in the setting of a hypertensive crisis. Both patients had been nonadherent to antihypertensive medications during travel. By contrast, 34 patients (31%) reported a health problem that was new and not related to a chronic condition diagnosed prior to travel. Of these, 24 (22%) patients experienced an infection; most commonly, respiratory tract infections and skin and soft tissue infections. There were no reported hospitalizations in this group.
Table 3. Self-reported health problems during travel
| ||Number (%)|
|Problem not associated with chronic conditiona||34 (31%)|
| Infection||24 (22%)|
| Respiratory infection||11 (10%)|
| Skin and soft tissue infection||6 (6%)|
| Diarrheal infection||5 (5%)|
| Urinary tract infection||2 (2%)|
| Accident/injury||6 (6%)|
| Other||4 (4%)|
|Problem associated with chronic conditiona,b||35 (32%)|
| Endocrine||8 (7%)|
| Gastrointestinal||7 (6%)|
| Pain||7 (6%)|
| Mental health||6 (6%)|
| Cardiovascular||6 (6%)|
| Pulmonary||3 (3%)|
| Renal||2 (2%)|
| Headaches/migraines||2 (2%)|
|Additional problems|| |
| Medication nonadherence||66 (60%)|
| Lost medications||3 (3%)|
A linear regression model using age of patient, duration of travel, travel destination, number of medications before travel, documented nonadherence to medications, and whether chronic disease management was discussed as part of pre-travel counseling found that the number of medications taken before travel was associated with increased likelihood of a health problem related to a chronic condition. Patients were categorized as taking a small (0–3), moderate (4–6), large (7–10), or very large (>10) number of medications. For each increase in category, the odds of experiencing a health problem related to a chronic medical condition increased by 4.13-fold.
A comparison of markers of chronic disease management before and after travel is described in Table 4. It did not reveal any statistically significant changes, except for an average increase in DBP of 3.6 mmHg among patients with hypertension (p = 0.01). Subgroup analysis revealed that travel to Africa and reported nonadherence to medications were associated with worsening blood pressure control. Patients traveling to Africa experienced an increase in both SBP (131.8 ± 16 vs 138.1 ± 17.7, 95% CI [−12.87, 0.34]) and DBP (70.6 ± 10.4 vs 74.9 ± 8.7, 95% CI [−8.28, –0.39]) when values before and after travel were compared. Travel to Asia was not associated with worsening of blood pressure. Patients traveling to Africa also experienced a decrease in BMI (29.1 ± 2.8 vs 28.6 ± 3.3, 95% CI [0.04, 0.80]). Patients who were nonadherent to medications during travel, not surprisingly, also had an increase in both SBP (130.0 ± 16.3 vs 135.1 ± 17.8, 95% CI [−9.86, –0.56]) and DBP (69.2 ± 9.7 vs 73.2 ± 10.0, 95% CI [−6.45,–1.72]).
Table 4. Chronic disease markers before and after travel
| ||Before||After||p Value||95% CI|
|Body mass index (N = 76)||28.3 ± 2.7||28.1 ± 3.0||0.21||(−0.406, 0.09)|
|Systolic blood pressure (N = 84)||129.3 ± 16.1||131.5 ± 16.4||0.22||(−1.29, 5.62)|
|Diastolic blood pressure (N = 84)||68.1 ± 12.6||71.7 ± 9.7||0.01||(−6.63, –0.88)|
|International normalized ratio (N = 3)||3.0 ± 0.1||2.6 ± 1.3||0.67||(−3.60, 2.87)|
|Low density lipoprotein (N = 58)||111.5 ± 39.5||108.3 ± 31.7||0.47||(−11.96, 5.60)|
|Serum creatinine (N = 12)||1.77 ± 0.86||1.73 ± 0.88||0.52||(−0.18, 0.10)|
|Hemoglobin A1c (N = 33)||7.55 ± 1.1||7.77 ± 1.3||0.33||(−0.24, 0.68)|
On average, patients included in this study took the same amount of chronic medications before and after travel, 7 ± 4 medications. Sixty percent of patients reported nonadherence to one or more prescribed medications during travel. Patients either chose not to take their medication(s) during travel or failed to bring an adequate supply for their entire trip. A linear regression analysis found that duration of travel increased the risk of medication nonadherence. For each additional month of travel, the odds of being nonadherent increased 1.44 times compared to one less month (p = 0.045; 95% CI: 1.01, 2.06).
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Little is known about the impact of travel on chronic disease management, especially among VFR travelers. This small study is an attempt to fill this important gap in knowledge. We found that nearly one-third of VFR travelers in our study population experienced health problems while traveling in Africa or Asia that were related to one or more chronic medical conditions. This rate exceeded that of travelers who reported an acute health problem related to an infectious disease. The two patients in our study requiring hospitalization after travel were admitted as a result of cardiovascular issues, and none required admission for an infectious illness. Although we found a low rate of travelers' diarrhea in our cohort (N = 5 or 4.5%), these rates were comparable to other reports of acute diarrhea in long-term or immigrant VFR travelers.[4, 8] Furthermore, we found very high rates of medication nonadherence during VFR travel, particularly with travel of longer duration. We also found that the likelihood of a health problem while traveling corresponded to the number of chronic medications the traveler was taking. These findings are important because we also found that the focus of pre-travel counseling in our clinic conformed to the traditional emphasis on vaccine-preventable illnesses, malaria prophylaxis, and advice on safe food and water. Prior studies have shown that the leading cause of death among travelers is cardiovascular disease, so the worsening of blood pressure control found among our African travelers is concerning.[21, 29] These results suggest that for VFR travelers on numerous medications or traveling for extended trips, it may be important for the pre-travel visit to include strategies for chronic disease management and medication adherence during travel.
Following this recommendation is likely to be challenging. In our study, the pre-travel visit occurred a median of only 7 days prior to departure, with a median visit length of only 30 minutes, compelling the provider to prioritize the focus of the visit. Prior studies have shown that VFR travelers tend to underestimate their risk and rarely seek care from specialized travel clinics. Therefore, the onus of providing this advice falls on primary care providers, who already have many competing priorities and increasingly constrained time to spend with patients.[4-7, 9, 10] Additionally, a specific barrier we have found in our clinic (in Washington State) to medication adherence is that those receiving Medicare, Medicaid, or hospital-sponsored charity care are usually limited to only a 30-day supply of medications, and many cannot afford to pay for additional supplies of medications out of pocket if their travels extend beyond this period.
There are several limitations to this study including our limited patient population and retrospective study design. Owing to the fact that ours is a primary care clinic, not a travel clinic, along with limitations to our electronic medical record system, it is not possible to easily identify all patients who are traveling. A small number were identified because travel counseling was explicitly identified as the reason for the visit. For the majority, they were identified by screening the records of patients who were given a prescription of doxycycline as a proxy for travel, but this may have missed those who did not inform their physician that they were traveling, traveled to nonmalarious areas, declined this medication, or received it from an outside pharmacy. In addition, the clinic records may underestimate the number of patients who ran out of medications or experienced problems while traveling, because this was not always asked about in post-travel visits or may not have been reported by the patient. Markers of chronic disease related to cardiovascular risk were prioritized in this investigation. However, the large number of health problems related to mental health conditions and high rate of respiratory infections potentially related to chronic respiratory conditions also warrant further study on the impact of VFR travel on other chronic conditions. Finally, although the mean time of follow-up from end of travel to being seen in clinic was 23 days, some patients were not seen until 4 months after they returned, which may have reduced the patient's recollection of health problems or the impact of travel on the variables measured.
Our study did not identify any statistically significant change in objective markers of chronic disease management, with the exception of a small worsening of DBP. The small sample size and retrospective nature of this study may have limited its ability to capture these changes. In addition, although some patients may have had worsening of chronic disease management due to issues related to medication nonadherence, others may have had improvements due to more positive changes in lifestyle. Our patients routinely report increased exercise, improvements in diet, and decreased stress levels while in their home countries during VFR travel. Our investigation was not able to capture these factors, with the exception of the important finding that travelers to Africa did have a small decrease in BMI after they returned. This decrease in BMI did not seem to correlate with diarrhea or other acute infections and we postulate that it is related to changes in activity level and diet during travel.