Acute phase markers are associated with reduced plasma lipid levels in a population of hospitalized elderly patients

BACKGROUND: Several epidemiological studies have documented the presence of a 'J' or 'U' association between total cholesterol levels and total mortality. Not only the mechanism underlying the association between increased mortality and low total cholesterol values is not completely clear, but the relationship itself also appears to be complex in the elderly. OBJECTIVE: The aim of the study was to evaluate the possible association between some biohumoral markers of the acute phase, comorbidity, disability, and reduced levels of some lipoprotein parameters in a sample of hospitalized elderly subjects. METHODS: 341 patients over 65 years of age (185 males, 156 females; mean age 76.2 years), consecutively admitted to our department from 1994 to 1995, were studied. Acute phase was defined as the simultaneous presence of: (1) increased alpha2-plasma protein on electrophoresis (>12%); (2) high fibrinogen concentration (>450 mg/dl), and (3) increased blood sedimentation rate (>15 and >20 mm 1 h in males and females, respectively). RESULTS: The prevalence of signs of acute phase was higher in males and in the youngest patients, but did not change with the level of comorbidity. Patients with signs of acute phase were characterized by lower total, low-density lipoprotein (LDL)- and high-density lipoprotein (HDL)-cholesterol levels compared to subjects without signs of acute phase; this difference was significant even after adjustment for indicators of comorbidity, disability, and nutritional status. Multivariate logistic regression analysis evidenced that the simultaneous presence of these three markers of acute phase was independently associated with low levels of total cholesterol [odds ratio (OR) 2.1, 95% confidence interval (CI) 1.1 - 3.9], and HDL-cholesterol (OR 2.3, 95% CI 1.2 - 4.2), considered as the sex-specific first quintile. CONCLUSION: The findings of this study demonstrate an independent association between acute phase markers and low levels of total and HDL-cholesterol, suggesting that recognized or subclinical diseases in elderly patients may determine a reduction in these plasma lipids. Low level of total and HDL-cholesterol should be considered as possible clinical markers of an underlying state of acute phase rather than a sign of malnutrition. Given the high prevalence of chronic diseases in the elderly, epidemiological studies addressing the lipid profile in this age group should take into account the possible confounding effect of the presence of signs of acute phase.