Associations Between Inflammatory Markers And Frailty In Hospitalized Elderly

Frailty is one of the most common geriatric syndromes in older adults with a feature of age-related decline in physiologic systems,which leads to decline in reserve of function and increasing vulnerability to stress.The core element is a series of clinical events,which are caused by the decline of the physiological reserve function of the elderly,the destruction of self balance,and the stimulation of the outside world.Not only can frailty lead to the decline of anti-stress ability in elderly,it also cause disability,functional decline,increased risk of hospitalization and death,and cause the long-term care needs and medical expenses increased.If the early identification of frailty and give it the corresponding treatment,it can reduce disability,institution admission and the medical / social costs,prefrail can be reversed to a healthy,some frailty can also be reversed to prefrail.Therefore,it is very important to understand the mechanism of frailty for early identification and treatment of frailty.However,the pathophysiological mechanisms related to the frailty is not very clear,inflammatory state is characterized by high level of inflammatory cytokines and many studies have confirmed that this state is closely related to the pathophysiological mechanism of the occurrence of frailty due to it damage the various organizations of the elderly directly or indirectly.Many studies have confirmed that C-reactive protein(CRP)and interleukin-6(IL-6)are two inflammatory factors associated with frailty,in other words,frailty elderly have higher CRP and IL-6 level.However,CRP and IL-6 is not unique to frailty,they are also affected by other diseases,such as cardiovascular disease,metabolic disorders,tumor,abnormal liver function and infections.Procalcitonin(PCT)has attracted attention due to its high specificity and good sensitivity for the diagnosis of bacterial infections,PCT is one of the most important infectious markers for clinicians to judge whether the patient is infected,to guide the use of antibiotics,and to judge the prognosis of patients.Frail elderly are more susceptible to infection,however,there is no correlation between PCT and frailty.ObjectiveThis was the first study to explore the relationship between the level of serum PCT in the elderly patients and frailty,taking into account PCT was a common infectiondisease biomarkers,the hospitalized elderly were divided into infection group and non-infection group for further subgroup analysis.Our intention was to determine whether PCT levels have relationship with frailty at different groups,and to confirm whether serum CRP and IL-6 levels are associated with frailty at same time.Materials and MethodsThe present study was a cross-sectional analysis of older inpatients(West China Hospital,Chengdu,China,June-December,2016)which was a part of the development process of opening an Acute Care of the Elderly Unit.Frailty assessment used questionnaire survey according to the FRAIL scale and all inpatients was divided into non-frail elderly(including robust and pre-frail)and frailty.The following data were collected from the inpatient hospital information system(HIS)of West China Hospital,including basic health information,hospitalization time,anti-inflammatory drugs use before admission,respiratory symptoms and pulmonary signs,chest CT or X rays,blood test results,discharge diagnosis,antibiotic use in hospital and outcome indicators.Serum PCT andIL-6 level was determined by electrochemiluminescence immunoassay(ECLI)assay,CRP was assessed with particle enhanced immunoassay and all samples were measured by the inspection department of West China Hospital.Finally,the data were collected to investigate the relationship between the levels of 3inflammatory factors and frailty and to analyze their clinical significance.ResultsA total of 435 patients in this study,the prevalence of frailty was 36.78%(160/435);frail group had higher levels of inflammatory factors(CRP,IL-6 and PCT)than non-frail group,(P=0.001;P<0.001;<0.001),but only PCT had the relationship with frailty after adjustments for several potential confounders.In CAP group,3inflammatory factors had no relationship with frailty by multivariate regression analysis.In non-infected group,the levels of IL-6 and PCT in frail group were higher than those in non-frail group(P=0.003;P=0.007),and CRP level had no difference between the two groups;IL-6 and PCT were significantly associated with frailty after adjusting for demographic data and lifestyle characteristics(L-6:OR=2.223;95% CI :1.063-4.650;P=0.034;PCT:OR=6.208;95% CI :1.993-19.336;P=0.002),however,after adjustingfor blood tests in our final multivariable model,only PCT(not IL-6 and CRP)was associated with frailty(OR=5.244;95% CI :1.622-16.947;P=0.006).The level of inflammatory factors in CAP group was higher than that in non-infected group.Regardless infection occurred,some elderly who had died in hospital had higher PCT level,and the PCT level had some value in predicting in-hospital mortality(AUC 0.719,95% CI,0.642-0.795).ConclusionInpatients had high prevalence of frailty;CRP,IL-6,PCT levels can't be used to speculate patients whether had frailty or not in CAP inpatients,in non-infected patients,PCT had more valuable than CRP and IL-6 to judge frailty.The level of inflammatory factors in CAP group was higher than that in non-infected group.Regardless infection occurred,some elderly who had died in hospital had higher PCT level,and the PCT level had value in predicting in-hospital mortality to a certain extent.