Serial Biomarker Testing and Cardiovascular Risk Stratification (ACHILLES)

Single measurements of cardiovascular risk biomarkers such as high-sensitivity C-reactive protein (hsCRP) and lipoprotein(a) [Lp(a)] are often used to classify patients as low- or high-risk, but biological and measurement variability means a single elevated value may not reflect a patient's true, sustained risk status. This study examines intraindividual variability in serial hsCRP and Lp(a) measurements among patients with repeated testing, to determine how often an initially elevated value normalizes on subsequent testing, and whether persistently elevated levels - rather than a single elevated measurement - better identify patients at genuinely increased cardiovascular risk.

Using retrospective, repeated-measures data, patients are classified by testing strategy: a single-measurement approach (elevated vs. not, based on the first available value) versus a serial-measurement approach (persistently elevated across multiple tests vs. transiently elevated vs. never elevated). Cardiovascular outcomes and all-cause mortality are compared across these classification strategies to assess whether transient biomarker elevation carries the same prognostic weight as persistent elevation, and whether repeated testing meaningfully improves risk stratification over a single measurement.

The findings are intended to inform whether current single-test-based risk classification should be reconsidered in favor of confirmatory or serial biomarker testing, for both hsCRP and Lp(a), in cardiovascular risk assessment.

Inclusion criteria

• Available Biomarker Measurement

Exclusion criteria

• < 18 years, Biomarker not available