Acute phase protein response to infection in elderly patients

The value of C-reactive protein in infection diagnosis and prognosis in elderly patients

BACKGROUND

The aim of this study was to determine the value of C-reactive protein level in the diagnosis and prognosis of infection in elderly patients.

STUDY POPULATION

This prospective study included inpatients in the palliative care unit during the 1-year period between January 2016 and January 2017. Patients' demographic data, Acute Physiology and Chronic Health Evaluation score, and Charlson Comorbidity Index were recorded.

RESULTS

A total of 233 patients were included in the study. A total of 199 instances of infection were diagnosed in 175 of those patients; 75.3% of the infections were detected at admission and 24.7% during hospitalization. At a cut-off value of 4.82, CRP value had 81.0% specificity and 75.4% sensitivity in the diagnosis of infection. Among the patients with infection, there was no difference between those who died and those who survived in terms of baseline CRP level, but a significant difference emerged in CRP level at 48 and 96 h. Factors which were found to significantly reduce survival time were the presence of chronic kidney disease, chronic obstructive pulmonary disease, hypoxia and tachycardia at admission, APACHE-II score over 20.5, initial albumin level below 2.44 g/dL, and serum CRP clearance rates of less than 11% at 48 h and 20% at 96 h.

CONCLUSION

In elderly patients with infection, the initial CRP value alone does not have prognostic value, but changes observed in serial CRP measurement are a valid indicator of prognosis.

C-reactive protein (CRP) measurement in geriatric patients hospitalized for acute infection

The physiology of inflammatory response is modified by the aging process and is substantially affected by multimorbidity and disability. Infection is the most frequent cause of acute inflammation in both adult and older subjects. C-reactive protein (CRP) is the most used biomarker of inflammation, and a substantial amount of literature has demonstrated its importance and clinical usefulness in adult subjects. However, the clinical significance of serum CRP determination has not been completely clarified in older subjects with acute infection, especially in the light of the age-related rearrangements in immunity and cytokine production. Thus, in the present review, we focus on the existing knowledge about serum CRP level interpretation in geriatric patients hospitalized with acute infection. Our aims were to determine the significance of CRP measurement at hospital admission for establishing a diagnosis of infection and/or a prognosis and to evaluate whether it is indicated to repeat hs-CRP measurements during hospital stay for monitoring disease course and, possibly, guiding the discharge timing. We concluded that CRP dosage at hospital admission is helpful to detect acute infection, and particularly sepsis, in geriatric patients, and that CRP elevation may provide valuable short-term prognostic information. At the current state of art, serial CRP measurements are instead not indicated to monitor disease course and plan hospital discharge in this setting.

Serum C-reactive protein as a biomarker for early detection of bacterial infection in the older patient

BACKGROUND

although C-reactive protein (CRP) is widely used in younger populations, its value for diagnosing bacterial infection in older population is not well established. This study examined the usefulness of serum CRP level in the early detection of bacterial infection in older patients.

METHODS

in a prospective cohort study, consecutive patients aged 70 years or over admitted to Aged Care wards were recruited. CRP levels were measured within 24 h of presentation, and their significance in predicting bacterial infections was analysed. The relationship between CRP and other clinical features of diagnosing bacterial infections (e.g. temperature, white cell count, neutrophil count, oxygen saturation, blood pressure and heart rate) was also examined.

RESULTS

a total of 232 patients were recruited over a period of 3 months. CRP levels were 21.3 +/- 36.0 and 150.5 +/- 114.1 mg/l (mean +/- SD) in the non-infection and infection groups, respectively (P < 0.001). We found that the CRP cut-off value of 60 mg/l had the best combination of sensitivity and specificity. At this level, the sensitivity of diagnosing bacterial infection was 80.7%, specificity 96.0%, positive predictive value 91.9% and negative predictive value 89.8%. CRP and temperature had higher sensitivity and specificity than white cell count and neutrophil count in the diagnosis of infection. For every 1-mg/l increment in CRP, the risk of bacterial infection increases by 2.9%.

CONCLUSION

CRP is a convenient and useful biomarker to predict early bacterial infection in older patients especially when other markers are atypical or not present.

Bacteraemia in the elderly: predictors of outcome in an urban teaching hospital

OBJECTIVES

To analyze the underlying factors of mortality in elderly adults with bacteraemia.

METHODS

The study included 238 episodes of bacteraemia in an urban public teaching hospital. Retrospective chart review recorded demographic information, comorbid conditions, length of stay, source of infection, and physiologic and laboratory data on admission.

RESULTS

Of the 238 episodes of bacteraemia, 128 patients were 65-74 years of age and 110 patients were > or =75 years of age. Eighty-one percent came from home. Fifty-four percent had Gram positive cocci detected in blood cultures and 36% had Gram negative bacilli. Factors associated with increased odds of mortality included underlying renal disease, admission to MICU, hypotension and hypoalbuminemia. Decreased odds of mortality were associated with being admitted from home and receiving appropriate antibiotics.

CONCLUSIONS

Bacteraemia in the elderly has a high mortality rate, but is not significantly increased in those >or =75 years of age. The recent microbiology has shifted from Gram negative bacilli to Gram positive cocci. Physiologic abnormalities on admission predict worse outcomes in the elderly bacteraemic patient. Hypoalbuminemia on admission is associated with higher mortality rates in the elderly.

The management of postsurgical pain in the elderly population

It is likely that the trend towards ever more aggressive surgery in elderly and possibly frail patients will continue, with the lifting of traditional age limits. Recent evidence has show that surgical trauma induces processes of nervous system sensitisation that contributes to and enhances postoperative pain and leads to chronic pain. This knowledge provides a rational basis for pro-active, pre-operative and post-operative analgesic strategies which can reduce the neuronal barrage associated with tissue damage. As well as a reduction or elimination of post-operative pain, an improvement in physiological variables, such as neuroendocrine stress responses and post-operative pulmonary function can be expected. Complete pain control cannot be achieved with a single agent or technique without significant serious adverse effects, a problem which is compounded in the elderly patient due to a combination of slower drug metabolism, decreased organ function and physiological changes in cardiovascular and respiratory reserves. A balanced analgesic regimen that includes an effective afferent block (regional analgesia) is more appropriate. By preventing postoperative pain and its associated neuroendocrine sequelae, major surgical procedures in traditionally unsuitable patients can be seriously considered.

C-reactive protein is more sensitive than erythrocyte sedimentation rate for diagnosis of infective endocarditis

The objective of this study was to evaluate the sensitivity of C-reactive protein (CRP) elevation compared to erythrocyte sedimentation rate (ESR), leucocyte count and thrombocyte count in the diagnosis of infective endocarditis (IE). It was designed as a prospective study of suspected episodes of IE in adults in tertiary care at a university-affiliated department of infectious diseases. In 89 episodes of IE, CRP was available from the start of treatment. Median age was 66 years, 45 were men and 44 women. Median CRP concentration was found to be 90 (range 0-357) mg/l with only 4% normal values. Episodes involving native valves had higher CRP than episodes occurring with prosthetic valves. Staphylococcal origin, short duration of symptoms, short duration of fever and highest recorded temperature all correlated to higher CRP levels. The CRP response was also prominent among patients > 70 years old. Among non-responders, a few cases with simultaneous cirrhosis were noted. ESR was less sensitive than CRP, with a normal level in 28% of the episodes. It was concluded that CRP determination is superior to erythrocyte sedimentation rate, leucocyte count and thrombocyte count in the diagnosis of infective endocarditis.

Influence of acute inflammation on iron and nutritional status indexes in older inpatients

OBJECTIVE

To investigate the relations between acute inflammation, as shown by high C-reactive protein (CRP) serum levels, and laboratory indexes of iron and nutritional status and to ascertain whether the presence of acute inflammation affects the diagnostic reliability of these indexes.

DESIGN

Cross-sectional study.

SETTING

Geriatric ward for rehabilitation.

PARTICIPANTS

A total of 163 patients, 77 men and 86 women aged 60 years or older.

MEASUREMENTS

CRP values > 1 mg/dL were considered to indicate the presence of acute inflammation. Iron status was explored by measuring erythrocyte mean cell volume (MCV), hemoglobin (Hb), serum iron (Fe), TIBC, percent transferrin saturation (% TS) and ferritin (SF). Nutritional status was determined by albumin (Alb) and prealbumin (pre-Alb) serum levels.

MAIN RESULTS

In the whole series, CRP correlated significantly with all iron status variables except erythrocyte MCV (directly with SF, inversely with the others) and correlated inversely with Alb and pre-Alb. Mean values of iron status variables were significantly different in patients with inflammation and those without: SF was higher and the other variables lower. Patients with low % TS (< 16%) showed a pattern consistent with iron deficiency. Compared to the group with normal values, they had more severe anemia, lower MCV, Fe, and SF, and higher TIBC; mean Alb, pre-Alb, and CRP values were not significantly different. The prevalence of inflammation was 50% (39.5% in the group with normal % TS). A similar pattern was observed in patients with microcytosis (MCV < 84 fL) associated with low % TS; dividing this subgroup according to SF values (low, < 30 micrograms/L) did not provide more information because patients with acute inflammation were excluded.

CONCLUSIONS

Patients with acute inflammation present altered iron status indexes that resemble those observed in the anemia of chronic disease. Fe, TIBC and SF lose diagnostic value. The concomitant presence of microcytosis and low % TS, and to a lesser extent the presence of one of these alterations, is suggestive of iron deficiency associated with inflammation and may warrant gastrointestinal tract investigations and ferrous salt treatment. Protein-calorie malnutrition seems to enhance the effects of inflammation on iron status indexes.

C-reactive protein as a diagnostic test of sepsis in the critically ill

Changes in the plasma concentration of C-reactive protein were assessed as a diagnostic test for sepsis in critically ill patients. Forty-nine episodes of secondary sepsis were identified in 31 patients. In 43 out of the 49 episodes there was a 25% or greater change in the concentration of C-reactive protein on the day that sepsis was diagnosed but in six episodes of sepsis the change was less than 25%. A 25% rise in the plasma concentration of C-reactive protein in the absence of other non-infective causes of a raised C-reactive protein, such as inflammation, tissue injury or surgery, is highly suggestive of infection, but failure of the C-reactive protein to rise does not eliminate a diagnosis of sepsis.

C-reactive protein: a critical review

We have reviewed the literature to determine the value of C-reactive protein (CRP) measurements in the diagnosis and management of a wide range of conditions. CRP levels are of value in 6 clinical situations: (a) monitoring the response to antibiotic treatment in patients with known bacterial infections, (b) in obstetric patients with premature rupture of membranes, a rise in CRP can give early warning of intrauterine infections, (c) differentiation between active disease and infections in patients with systemic lupus and ulcerative colitis where the level of response to active disease has been previously established, (d) as a measure of disease activity and response to disease-modifying drugs in rheumatoid arthritis, (e) early detection of complications in postoperative patients, (f) in differentiating between infection and graft-versus-host-disease in bone marrow transplant patients. CRP levels have been used in an attempt to differentiate between bacterial and viral infections in various clinical situations, however the published literature does not support this role.

Influence of menstrual cycle phase on serum concentrations of alpha 1-acid glycoprotein

Serum concentrations of alpha 1-acid glycoprotein (AAG) were studied in nine healthy women at four times in their menstrual cycles. AAG concentrations were significantly higher on day 4 than on days 12, 20, and 28 (with the first day of menstrual flow considered to be day 1). The mean AAG concentration (mg dl-1) on day 4 was 78.55 +/- 5.03 (mean +/- s.e. mean), 70.19 +/- 4.80 on day 12, 70.63 +/- 6.67 on day 20, and 70.40 +/- 5.97 on day 28. Although these results should be considered preliminary because of the small sample size, we conclude that physiologic changes over the course of the menstrual cycle may affect serum AAG concentrations. Since AAG is a major binding protein for several important drugs, the potential exists for altered drug binding and drug effects, and further study of individual drugs is justified.

Prevalence of protein-energy malnutrition in a large population of elderly people at home

The prevalence of protein-energy malnutrition (PEM) was examined in 1206 randomly selected elderly people aged 65 to 80 years living in their own homes. Nutritional assessment was based on weight loss, weight index, triceps skin fold, arm muscle circumference, serum albumin and prealbumin, and delayed cutaneous hypersensitivity (DCH) reaction. The prevalence of PEM was 5 per cent. If people with signs of inflammation were excluded, the prevalence of PEM was 3.5 per cent. When other nutritional indices, used by other authors among hospitalized patients, were applied to our sample prevalence values from 2.6 to 4.1 per cent were obtained. the prevalence was not related to sex or age. DCH increased the sensitivity of the screening method but causes of anergy other than PEM must be taken into account. It is concluded that PEM, in a degree shown to impair the prognosis at hospital, does occur among elderly people at home in an industrialized country.

A comparison of the acute-phase response in middle aged and elderly patients

The acute phase response in middle aged and elderly patients was compared by measuring the ratio of the peak C-reactive protein to peak creatine kinase level during the three day period after acute myocardial infarction. No difference in ratio was observed between a middle aged group of 14 patients (10.2 +/- 4.0 mean +/- s.e.), and an elderly group of 13 patients (9.1 +/- 1.5). C-reactive protein levels in two groups of middle aged and elderly control patients were similar (10.1 +/- 0.04 mg/l and 11.8 +/- 0.10 mg/l respectively). Production of C-reactive protein does not appear to be impaired in the elderly.

Cimetidine does not increase alpha 1-acid glycoprotein serum concentrations

Serum concentrations of alpha 1-acid glycoprotein (AAG) were studied in six healthy, male volunteers before and after administration of cimetidine, 300 mg by mouth every 6 h for 2 days. Serum AAG concentrations were measured at three different times during the first day, i.e. before cimetidine administration, and on the fourth and sixth days, after commencing cimetidine administration. Neither cimetidine treatment nor time of day contributed significantly to differences in serum AAG concentration, and no interaction of these factors was observed. It is concluded that altered drug-AAG binding as a result of cimetidine therapy is not likely to be an important mechanism contributing to cimetidine drug interactions.