3.2: Reservoir Pressure Integral is Independently Associated with the Reduction in Renal Function in an Older Population

Background Central haemodynamic parameters derived from reservoir pressure analysis (RPA-parameters) exhibit prognostic utility. Alterations in reservoir function could have an unfavourable influence on target organs, such as the kidneys. We determined in older adults whether these RPA-parameters would be associated with the reduction in estimated glomerular filtration rate (eGFR) during a 3-year follow-up period. Methods We studied 544 individuals (69.4 ± 7.9 yrs, 195F, 235CVD) at baseline and after 3 years. RPA-parameters including reservoir pressure integral (INTPR), peak reservoir pressure, excess pressure integral, systolic and diastolic rate constants were obtained by radial artery tonometry. Results After 3 years, 95 individuals (72.4 ± 7.6 yrs, 26F) had an eGFR reduction of more than 5 ml/min/1.73 m 2 /year. A multivariate logistic regression analysis revealed that baseline INTPR was independently associated with the eGFR reduction after adjusting for conventional risk factors and baseline renal function [odds ratio 0.975 (95% CI, 0.958–0.993), p < 0.01]. When the eGFR reduction was expressed as a continuous variable, baseline INTPR was also independently associated with changes in eGFR ( β = 0.115, p < 0.01; multivariate linear regression with adjustment for conventional risk factors and baseline renal function). These associations remained unchanged after further adjustments for central artery stiffness or traditional central haemodynamic parameters. No other RPA-parameters exhibited significant associations. Conclusions These findings demonstrate that baseline INTPR is independently associated with the eGFR reduction in older adults, suggesting that INTPR may play a role in the functional decline of the kidneys.