Serum albumin trajectories over five years predict mortality in peritoneal dialysis: a group-based trajectory modeling study

Serum albumin is a key biomarker of nutrition in patients receiving peritoneal dialysis (PD). However, prior studies have largely relied on single or averaged measurements, which fail to capture long-term dynamic changes. This study aimed to identify five-year serum albumin trajectories in PD patients and evaluate their associations with mortality. We conducted a retrospective cohort study of adult PD patients in a tertiary hospital in Beijing, China, with at least one annual albumin measurement during the first five years of PD. Group-based trajectory modeling (GBTM) identified latent albumin trajectory patterns. Multinomial logistic regression was used to examine baseline factors associated with trajectory membership, and Cox proportional hazards models were used to assess associations with all-cause mortality. Among 153 patients, three distinct albumin trajectories were identified: high-stable (HS, n = 56; 36.6%), low-stable (LS, n = 50; 32.7%), and updown (UD, n = 47; 30.7%). Compared with the LS group, the UD group was associated with younger age (OR = 0.90, 95% CI = 0.86–0.95), while the HS group had a larger body surface area (OR = 1.61, 95% CI = 1.08–2.39). In multivariate Cox models, the HS group had lower all-cause mortality rates than the LS (HR = 0.40, 95% CI = 0.18–0.87) and UD groups (HR = 0.28, 95% CI = 0.13–0.61). In exploratory cause-specific analyses, the HS group showed a nominally lower risk of cerebrovascular mortality than the UD group in the crude model (HR=0.15, 95% CI=0.03–0.84); however, all cause-specific analyses were limited to crude estimates because of the very small numbers of cardiovascular (n=11), cerebrovascular (n=13), and peritonitis-related deaths (n=11) and should be considered hypothesis-generating only. Five-year serum albumin trajectories show heterogeneity among PD patients and provide prognostic information beyond single measurements. A high and stable albumin trajectory is associated with the most favorable survival. However, these findings are derived from a cohort of patients who survived at least five years on PD; they support the potential utility of trajectory-based nutritional assessment for risk stratification among long-term PD survivors, but do not apply directly to the broader incident PD population.