Novel equations for estimating intraperitoneal pressure among peritoneal dialysis patients

BACKGROUND: Increased intraperitoneal pressure (IPP) is associated with abdominal wall complications and technical failure in peritoneal dialysis (PD). Since the standard measurement of IPP is limited due to its cumbersome procedures, we aimed to develop and validate equations for estimating IPP. METHODS: We performed a cross-sectional study with a total of 200 prevalent PD patients who were divided into development and validation datasets after random sampling matched by body mass index. The IPPs were measured using the Durand method, with whole-body and abdominal anthropometry indices collected. Equations with 2.0-L and 1.5-L fill volumes were generated by stepwise linear regression modelling. The bias, accuracy and precision of the estimated IPP (eIPP) with 2-L and 1.5-L fill volumes were compared with actual IPPs by the Durand method. The eIPP for the 2-L fill volume was also compared with other existing equations. RESULTS: Two new equations incorporating waist circumference and height from the decubitus plane to mid-axillary line were generated. The eIPPs exhibited small biases in relation to the Durand method , with median differences of −0.24 cmH(2)O and −0.10 cmH(2)O for 2 L and 1.5 L, respectively. The precisions evaluated by the standard deviation of the absolute value of the differences were 2.59 cmH(2)O and 2.50 cmH(2)O, respectively. The accuracies evaluated by the value of the percentage of estimates that differed by >20% for the eIPP were 26% for 2.0 L and 27% for 1.5 L. Better bias, precision and accuracy were observed for the eIPP equation compared with other existing equations for the 2.0-L fill volume. CONCLUSIONS: We provided two new equations developed from abdominal anthropometry indices to accurately estimate the IPP in the PD population.