Cumulative C-Reactive Protein Levels and Progression of Malnutrition in Dialysis Patients: A Longitudinal Study

Malnutrition is a serious complication in dialysis patients that develops slowly but steadily. Cross-sectional studies may not adequately characterize this complication because not only the intensity but longitudinally cumulative effect should also be taken into consideration. Relationship between time-dependent changes in a nutritional marker, Geriatric Nutritional Risk Index (GNRI), and cumulative C-reactive protein (CRP) values was examined whether both intensity and duration of inflammation correlated with time-dependent progression and severity of malnutrition over 3 years, retrospectively.

One hundred and sixty-four dialysis patients were examined over 3 years retrospectively. Based on analysis of clinical and laboratory findings over a period of 3 years, patients were divided into 2 groups: those with a >3.0 decrease in GNRI after 3 years (n = 84) and those in whom GNRI was unchanged (n = 80).

When comparing the 2 groups at 3 years, the GNRI-decreased group had 12% lower serum albumin (p < 0.001) and lower levels of creatinine (9%, p < 0.001), BUN (6%, p < 0.05), total cholesterol (6%, p < 0.05), and low-density lipoprotein cholesterol (10%, p < 0.01), which suggest onset of malnutrition. CRP levels, routinely measured twice a month in all patients, were summed to calculate the cumulative CRP. Cumulative CRP after 3 years was 57.6 ± 7.8 (mg/dL/3 years) in the GNRI-decreased group, which was significantly higher than that in the GNRI-unchanged group (38.6 ± 3.9; p < 0.05). Over 3 years, the GNRI-decreased group showed a time-dependent increase in cumulative CRP alongside a time-dependent decrease in the GNRI, producing an obvious mirror image; however, such inverse correlation was absent in the GNRI-unchanged group.

A long-term perspective is needed in the management of malnutrition in dialysis patients because this complication develops progressively and is often irreversible when diagnosed. Cumulative CRP values may be useful in evaluating the degree of the progression of malnutrition in following up individual patients longitudinally.