BACKGROUND: Preclinical heart failure (PHF) is an early stage in the heart failure continuum, yet practical indices for mortality risk assessment remain understudied. HYPOTHESIS: The C-reactive protein-albumin-lymphocyte index (CALLY), red cell distribution width-albumin ratio (RAR), and blood urea nitrogen-albumin ratio (BAR) are associated with mortality and provide additional predictive information among adults with PHF. METHODS: We analyzed adults aged ≥ 20 years with PHF from the National Health and Nutrition Examination Survey (NHANES) 1999-2010. PHF was defined by hypertension, diabetes, obesity, atherosclerotic cardiovascular disease, or prior myocardial infarction, without diagnosed heart failure. The indices were derived from baseline laboratory measurements and log-transformed. Mortality was ascertained through December 31, 2019. Associations were assessed using survey-weighted Cox models; nonlinearity, subgroup consistency across different PHF compositions, incremental predictive performance, and sensitivity analyses, including competing-risk models, were evaluated. RESULTS: Among 14 717 adults with PHF contributing 186 678.5 person-years, 3801 all-cause and 1226 cardiovascular deaths occurred. Per standard deviation increase, ln CALLY was associated with lower all-cause and cardiovascular mortality (HRs, 0.85 and 0.87), whereas ln RAR (HRs, 1.28 and 1.24) and ln BAR (HRs, 1.09 and 1.18) were associated with higher mortality. ln RAR showed the most consistent improvement in exploratory incremental predictive performance beyond the base model. The directions of association were broadly consistent across different PHF compositions, and the findings remained robust in sensitivity analyses. CONCLUSIONS: CALLY, RAR, and BAR were independently associated with mortality in adults with PHF; RAR may improve mortality risk assessment.