Serum total protein-to-albumin ratio and adverse clinical outcomes in patients with diabetes and chronic kidney disease: a comparative study of US and Chinese cohorts.

OBJECTIVE

This study aimed to explore the predictive value of serum total protein-to-albumin ratio (TAR) for all-cause mortality and other adverse clinical outcomes in patients with diabetes mellitus (DM) and chronic kidney disease (CKD).

METHODS

Data were obtained from two cohorts: 1628 patients with DM and CKD in cohort 1 from the National Health and Nutrition Examination Survey and 341 renal biopsy-confirmed diabetic nephropathy (DN) patients in cohort 2 from West China Hospital of Sichuan University. Patients were grouped by the TAR levels. TAR was calculated as serum total protein divided by albumin. The primary outcome was all-cause mortality. Cox proportional hazards regression assessed associations between TAR and adverse clinical outcomes, adjusting for demographic, clinical, and laboratory variables. Stratification, interaction, and correlation analyses were performed.

RESULT

In cohort 1, higher TAR independently increased all-cause and cardiovascular mortality risk (HR 1.60, 95% confidence interval (CI) 1.18-2.17, HR 1.97, 95% CI 1.09-3.58, respectively). Subgroup analyses showed significant association between TAR and all-cause mortality in participants with albumin creatinine ratio (ACR) < 30 mg/g (HR 2.34, 95% CI 1.15-4.75), with an interaction observed for ACR (P for interaction = 0.048). Patients in the high TAR group with estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73m had higher risk of cardiovascular mortality (HR 2.56, 1.1-5.98), with an interaction observed for eGFR (P for interaction = 0.018). In cohort 2, higher TAR was associated with risk of all-cause mortality and progression to ESRD in the univariate analysis (HR 2.46, 95% CI 1.18-5.11, HR 2.02, 95% CI 1.47-2.79, respectively). After adjustments, point estimates of HR decreased and 95%CI narrowed. TAR was positively correlated with systolic blood pressure, proteinuria, creatinine, renal pathological classification, renal interstitial fibrosis and tubular atrophy, and interstitial inflammation, while negatively correlated with eGFR, total protein, albumin, and hemoglobin.

CONCLUSION

Higher TAR was associated with increased all-cause and cardiovascular mortality in DM and CKD patients. Clinicians can use TAR to better stratify risk and guide treatment, improving outcomes.