The Effect of Low-grade Inflammation on Body Composition in Peritoneal Dialysis Patients.

OBJECTIVE

Kidney dialysis patients are at an increased risk of sarcopenia and mortality. Although there are many potential causes, the effect of chronic inflammation on changes in body composition in peritoneal dialysis (PD) over time was reviewed.

METHODS

Changes in body composition were measured by multifrequency bioimpedance in PD outpatients attending routine clinic review with sustained normal or raised C reactive protein (CRP) concentrations, excluding patients with peritonitis, and other acute hospitalizations.

RESULTS

Body composition was measured; median 12 (11-14) months apart in 427 PD outpatients (59.5% male, 37.2% diabetic), median dialysis vintage 12 months, 215 sustained normal CRP, and (≤5 mg/L) versus 212 sustained raised CRP (9 [6-19] mg/L). Body composition did not differ initially, but over time whereas there were no changes in fat mass, fat-free mass index remained stable in the normal CRP group (17.8 ± 2.3 vs 17.9 ± 2.4) but decreased in the raised CRP group (18.0 ± 2.6 vs 14.4 ± 2.6, P < .05), and over time serum albumin was lower in the raised CRP group (36.8 ± 4.7 vs 38.8 ± 4.0, P < .001). Estimated dietary protein intake declined over time in both groups but remained lower in the raised CRP group (0.83 ± 0.32 vs 0.87 ± 0.21 g/kg/day, P < .05). In a multivariable model, loss of lean body tissue was associated with persistently raised CRP (odds ratio 2.6, 95% confidence intervals 1.58-4.2, P < .001).

CONCLUSION

Sustained low-grade inflammation leads to a loss of lean body tissue in PD outpatients. Studies are required to determine whether treating the causes of, and reducing, low-grade inflammation results in prevention of lean tissue loss.