Abstract
<title>Abstract</title> <p>Background Age-related decline in kidney function is associated with adverse geriatric outcomes such as cognitive impairment, falls, and sarcopenia. In older adults, creatinine-based estimates of glomerular filtration rate (eGFR) may underestimate renal impairment due to reduced muscle mass, whereas cystatin C (CysC) may better capture functional vulnerability. Evidence from Latin American aging populations remains limited. Objective To evaluate associations between creatinine- and cysC- based kidney function estimates, cognition, sarcopenia indicators, falls, and ApoE ε4 genotype in older adults from Panama. Methods This study included 583 adults aged ≥ 65 years from clinical (n = 261) and community (n = 322) cohorts of XXXX (anonymized data for review). Blood creatinine and cysC were measured, and eGFR was estimated using creatinine-, cysC-, and combined- based equations. Cognitive function, body mass index (BMI), handgrip strength, and falls history were assessed. Multivariable regression models adjusted for sociodemographic factors, and comorbidities were applied. Results Creatinine-based eGFR classified most participants as having preserved kidney function, whereas cysC–based estimates identified a higher prevalence of reduced renal function, particularly among older adults in the community-based cohort (73%). Creatinine-based eGFR was associated with BMI, subjective memory complaints, and global cognitive performance. In contrast, cysC–based and combined eGFR were positively associated with falls, number of falls, and recurrent falls. ApoE ε4 status showed no significant associations. Conclusions Different kidney function biomarkers reflect distinct dimensions of aging-related vulnerability. Incorporating cysC alongside creatinine may improve risk stratification for functional outcomes in older adults, particularly in underrepresented populations.</p>