Low transthyretin concentration linked to adverse prognosis in elderly inpatients.

Background: To investigate the association between low transthyretin (prealbumin) concentration and mortality or readmission for all causes in elderly inpatients.

Methods: This analysis is based on a prospective cohort study conducted from September 2018 to April 2019 in ten wards of three tertiary referral hospitals in Beijing. Patients aged 65 years or older were enrolled, and their clinical data, laboratory test results, and auxiliary test results for patients were collected. A three-year follow-up was conducted with patients. Based on the 5th and 95th percentiles of transthyretin concentration, patients were split into three groups. The correlation between transthyretin concentration and the outcome of elderly hospitalized patients was investigated. The primary outcome of the research was death or readmission from all causes within three years.

Results: Among the 636 individuals in the study, 335 (52.7%) were males, with a median age of 74.7 years (interquartile range [IQR]: 69.3-80.1). During a median follow-up period of 1,099.0 days (IQR: 1,016.3-1,135.0), 363 individuals (57.0%) experienced all-cause mortality or readmission events. Patients with transthyretin concentrations at or below the 5th percentile had a significantly increased risk of all-cause mortality or readmission compared to those with concentrations between the 5th and 95th percentiles (hazard ratio [HR]: 2.25; 95% confidence interval [CI]: 1.55-3.26). Even after adjusting for potential confounders, low transthyretin concentration remained an independent risk factor for poor prognosis in elderly inpatients (HR: 1.84; 95% CI: 1.03-3.28). Since women have consistently lower baseline transthyretin levels than men, we performed gender-specific analysis. We found that low transthyretin concentration is an independent risk factor for adverse prognosis in elderly male inpatients (HR: 2.99; 95% CI: 1.35-6.62) but not in females.

Conclusions: Low transthyretin concentrations are associated with increased all-cause mortality or readmission in elderly inpatients, particularly among male patients.