Biological age is a key determinant of disease progression and increased morbidity. However, it is unclear whether multimorbidity is associated with low-grade inflammation or gait speed in octogenarians.

To examine cross-sectional associations between commonly used comorbidity indices and either elevated high-sensitivity C-reactive protein (hsCRP) or reduced gait speed in community-dwelling non-frail adults aged 80 and older.

a total of 404 community-dwelling older adults (mean age: 83 ± 3 years) were assessed for multimorbidity, gait speed, and hscrp. five comorbidity indices were calculated: charlson comorbidity index, cumulative illness rating scale for geriatrics, elixhauser comorbidity index (eci), rockwood frailty index, and a weighted modified disease count. binary logistic regression was used to analyze associations with elevated hscrp (>3.0 mg/l) and reduced gait speed (<0.8 m/s).

Of the indices evaluated, only the ECI showed a significant association with elevated hsCRP (adjusted odds ratio [aOR] = 1.18, 95% CI: 1.03–1.35; p = 0.020). When stratified by gender, this association remained significant in men (aOR = 1.29, 95% CI: 1.053–1.59; p = 0.014), but not in women. Furthermore, none of the comorbidity indices were significantly associated with low gait speed.

Among the comorbidity indices assessed, only the ECI demonstrated a modest yet significant association with hsCRP levels in individuals aged 80 years and older. In contrast, no significant associations were observed between any of the comorbidity indices and reduced gait speed in this population. This highlights the importance of comprehensive care, including individualized lifestyle interventions, nutritional support, and timely pharmacological adjustments for effective chronic disease management.