Serum C-reactive protein as a marker for infection and inflammation in regular dialysis patients

Serum C-reactive protein (CRP) concentration was measured in 98 hemodialysis (HD) patients and 68 continuous ambulatory peritoneal dialysis patients (CAPD). The effect, if any, of a HD session on serum CRP level and the usefulness of CRP in diagnosing and monitoring proven inflammatory disease were studied. Seventy-five percent of CAPD patients without evidence of inflammation had CRP levels within the quoted normal range (< 10 mg/l), as compared with only 47% of HD patients also without evidence of overt inflammation (p < 0.001). No significant change in the CRP level was detected during a hemodialysis session. Twenty-four patients with overt inflammation (due mainly to infection) were studied, 22 of whom had CRP levels of > 50 mg/l. These increased CRP levels fell with treatment. A CRP level of > 50 mg/l proved highly suggestive of a significant inflammatory process and a value of < 10 mg/l always excluded it. The total period of time on the regular dialysis program was not related to the CRP level. A subclinical inflammatory response resulting in a raised CRP is very common in our hemodialysis patients and less so in CAPD patients. Possible reasons for this are discussed. However, CRP is still useful in the diagnosis and monitoring of response to treatment of inflammatory disease if the level is > 50 mg/l or serial/baseline measurements are available for comparison. Whether any relationship exists between elevation of CRP and the well-documented increased risk of cardiovascular death in dialysis patients is currently unknown.