SAN FRANCISCO -- Women and liver transplant waitlists, the impact of insurance on waitlist outcomes, and the tie between obesity and waitlist representation were highlighted in a group of poster presentations at the annual Liver Meeting, sponsored by the American Association for the Study of Liver Diseases (AASLD).
Women on the Waitlist
Women with cirrhosis on the liver transplant waitlist had more hospitalizations and inpatient days in 1 year compared with men with the same diagnosis, according to data from a University of California San Francisco (UCSF) study.
Overall, 54% of women were hospitalized within 12 months of enrollment versus 34% of men (OR 1.6, 95% CI 1.0-2.4, P=0.03), an association which persisted after adjusting for factors associated with severity of illness, such as Model of End Stage Liver Disease Sodium (MELDNa) scores, ascites, albumin, and frailty (odds ratio 1.64, 95% CI 1.05-2.56, P=0.03), reported Jessica Rubin, MD, of UCSF, and colleagues.
Women also had more inpatient days than men on average (2.5 vs 0, P=0.02), an association that remained significant after adjusting for MELDNa and albumin (incidence rate ratio 1.92, 95% CI 1.23-2.99, P=0.004), they reported.
Rubin said it has been well-established that women waiting for a liver transplant may have worse outcomes than men, but the mechanisms for this disparity remain unclear. She told ֱ her group hypothesized that hospitalization would be a sufficient surrogate marker for disease severity, and that "if there were differences in hospitalization, maybe that could explain how the disease trajectory is different in women compared with men."
The researchers collected data from 392 adults with cirrhosis listed for liver transplantation and enrolled in the Functional Assessment of Liver Transplantation Study between March 2012 to December 2014. Between the 161 women and 231 men included, no significant differences in characteristics were found, besides the percent of each group that had alcoholic cirrhosis (P<0.01), the authors report.
Rubin noted that these differences held true for each subcategory of patients they tested, including patients who died, were delisted, or remained on the waitlist, she said.
Insurance and Drop-Out Rates
Patients with public insurance had worse waitlist outcomes versus those with private insurance, despite having similar tumor-related characteristics, according to a retrospective cohort study.
In a sample of 705 adult patients with hepatocellular carcinoma listed for liver transplant, 22% of patients with Kaiser insurance dropped out due to tumor progression within 2 years of listing compared with 36% of patients with a non-Kaiser private insurance (P=0.19) and 36% of patients with public insurance (P<0.001), reported Liat Gutin, MD, of UCSF, and colleagues.
They found the risk of dropout was significantly increased for patients with public insurance (hazard ratio 1.69, P=0.005) versus patients with Kaiser insurance. It was also increased for patients with other non-Kaiser private insurance (HR 1.40, P=0.10) compared with those with Kaiser, although not significantly.
Researchers also tested for tumor characteristics such as alpha-fetoprotein (AFP), size, and number of local-regional treatments, and all of these factors were similar across insurance groups. Overall, waitlist dropout was also significantly associated with an AFP over 100 ng/ml (HR 2.8, P<0.001), higher MELD scores at listing (HR 1.06 per point, P<0.001), and three lesions at listing (P=0.004), the authors reported.
Gutin told ֱ that follow-up is an essential component of these dropout rates, and that these results could potentially be explained to high provider involvement, particularly with patients who may come from lower socioeconomic backgrounds.
Of the 705 sampled, 50% had Kaiser insurance, 22% had private non-Kaiser insurance, and 28% had public insurance. Most of the patients in the public insurance group were non-white (63%), with the highest proportion of non-U.S. citizens (18%) and the lowest education level, compared with the other two groups (P<0.001 for all). Patients data was collected from the UCSF center from 2010 to 2016.
Obesity Waitlist Representation
Despite obese patients (BMI >30) comprising a substantial proportion of the liver transplant waitlist compared with the general population, patients with certain classes of obesity may be underrepresented, according to an analysis of variance (ANOVA).
Compared with the general population, the prevalence of patients with class I (+4.0, P<0.01) and class II obesity (+4.43, P<0.01) was overrepresented on the waitlist, reported Yumi Ando, MD, of Oregon Health and Science University in Portland, and colleagues.
And although there was a weak correlation between listing and prevalence for class II patients (R=0.55, P=0.04), there was no correlation between the prevalence of patients with class III obesity and their representation on the waitlist (R=0.34, P=0.3), the authors stated. This "wide regional variation" that exists in patients with class III obesity warrants further research in the effect of potential factors such as socioeconomic status, access to healthcare, and center experience, the authors wrote.
Ando's group estimated the prevalence of adult obesity using the Behavioral Risk Factor Surveillance System (BRFSS) and the prevalence of obesity in waitlisted adults using the Standard Transplant Analysis and Research (STAR) database. They stratified by class I (BMI 30 to <35), class II (BMI 35 to <40), and class III (BMI 40).
Disclosures
The study by Rubin's group was funded by the National Institute of Diabetes and Digestive and Kidney Diseases and the National Institute on Aging.