C-reactive protein levels in dialysis patients are highly variable and strongly related to co-morbidity.

Abstract

Sir, In recent literature, a strong emphasis has been placed on elevated C-reactive protein (CRP) levels as an important risk factor for morbidity and mortality [1,2]. Moreover, a relationship has been observed between elevated CRP levels, atherosclerotic plaques and malnutrition (the MIA syndrome) [3]. Nevertheless, by clinical impressions in our dialysis unit, we first noted a large variability in CRP levels and, furthermore, had the feeling that changes in CRP levels were highly related to intermittent or chronic (co-)morbidity. In the literature, data on the relationship between changes in CRP levels and intermittent morbidity are scarce [4], as are data on the variability of CRP levels per se in haemodialysis patients. The aim of the present study was to observe the variability of CRP levels and also to make an attempt to link elevated CRP levels to intermittent clinical events. CRP levels [non-sensitive assay (Syncron LX 20; Beckham Coulter, CA); cut-off point 2 mgul] were assessed at monthly intervals in all haemodialysis patients in our unit (ns60; mean age 6810 years; 28 males, 32 females) over a 3 month period. Moreover, all patients were seen weekly on clinical rounds, during which special emphasis was placed on intermittent clinical events during the weekly period. If necessary, clinical rounds were followed by additional laboratory, bacteriological and radiological examinations, based on the complaints of the patients. The correlation between the CRP levels at the three time periods was assessed by Kendall’s t. Median CRP levels at months 0, 1 and 2 were 11 mgul (2–394), 9 mgul (2–176) and 9 mgul (2–565), respectively. The non-parametric correlation coefficient between CRP levels at the start of the study and 1 month later was rs0.55 (P-0.01), and 0.40 (P-0.01) for the correlation between CRP levels at the start of the study and those 2 months later. In 92% of the patients, CRP levels were ) 2m gu lo n at least one occasion, whereas in 68% of patients, CRP levels were )10 mgul on at least one measurement. In 96% of the patients with CRP levels )10 mgul, significant clinical events anduor chronic co-morbidity were observed [acute or chronic inflammatory events (61%), malignancies (7.3%), recent surgery (4.9%), fractures (7.3%), symptomatic coronary artery disease (4.9%), active vasculitis (2.4%), gastrointestinal bleeding (2.4%)]. In contrast, in the 14 patients with CRP levels varying between 2 and 10 mgul during the three occasions, only in one patient (7.1%) did a clinical event become apparent. Three patients died during the study period (5%) (one myocardial infarction, one postoperative after aortic valve replacement and one terminal multiple myeloma), whereas 11 patients (18.3%) were admitted to the hospital ward.