Our study is one of the first to evaluate the impact of physical and cognitive status on the risk of subsequent events in elderly patients hospitalized for CVD. In common with previous studies, we found that elder patients with HF[26], DM[27], previous stroke[28], non-married[29], severe MNA-SF[30] and decreasing FT3[31] at baseline are more likely to have adverse events, but after being adjusted, only physical and cognitive frailty, HF and severe MNA-SF can be used as a predictor of short term prognosis. Patients with cognitive frailty experienced about 2.5 times more non-elective hospital readmission or death than robust patients. The significance of physical frailty assessed by Fried phenotype in predict of non-elective hospital readmission or death within 6-month in elderly patients with CVD increased significantly after the diagnosis of cognitive impairment was added. In our opinion, these findings support the routine use of MMSE + CDT-Fried phenotype for improving risk stratification in elder inpatients with CAD. Patients with cognitive frailty should need a closer follow-up to reduce their high readmission rate.
The detection of impaired physical performance and cognition in elder patients with CVD is essential for clinical management and therapeutic decision. Increasing age is an obvious risk factor for frailty[22], and patients admitted to hospital for CVD are more older. The most commonly used frailty assessment tools were the Frailty Index, the Clinical Frailty Scale, and the Fried phenotype[32], and there is a requirement for an assessment tool that can be used conveniently, rapidly, and securely in clinical practice for screening decreased physical performance, therefore, the Fried phenotype seems to be the best choice, which is a brief, interview and simple physical tests combined and easy to assessment instrument. There are recent studies concluding that an indicator of frailty in routine care is related to readmission or mortality in patients[33, 34]. Vidan and colleagues included 450 patients aged 70 and older and found frailty to be an independent predictor of 12-month readmission[35]. In a longitudinal cohort Study examined the effect of frailty phenotype and cognitive impairment on mortality in community for a 5-year, frailty and cognitive impairment (MMSE < 21) were significant predictors of mortality[36]. The primary aim of the present study was to assess the utility of a combination developed using the MMSE + CDT and the Fried phenotype for predicting non-elective hospital readmission or death within 6-month in elderly inpatients with CVD. The results of the present study show a strong association between the presence of physical or cognitive frailty and the risk of follow-up, even after controlling for multiple variables (including age, sex, education level, marital status, the presence of DM, HF and previous stroke), which is identical with others results of study[37]. Sensitivity analysis for the association between the MMSE + CDT-SPPB confirmed these results, and it seems to have a higher predictive value for prognosis. Both the Fried phenotype assessment and SPPB test were performed safely even in patients with various chronic diseases. In the present study, there were no adverse events caused by the assessment and test.
Cognitive impairment is a risk factor for adverse events in patients with HF[13]. In older women free of prevalent CVD at baseline, lower baseline cognitive function or decline increased risk of incident CVD, CVD death, and all-cause mortality[10]. To the authors’ knowledge, this study is the first to formally assess the MMSE + CDT as a predictor of clinically relevant outcomes in patients with CVD. But We found that cognitive impairment alone can not be a predictor of non-elective hospital readmission or death in elderly inpatients with CVD, only combined with physical frailty that would be a sensitive prognostic indicator.
In terms of laboratory indicators, a reduction in FT3 may be considered to be the consequence of multiple events, such as malnutrition as well as acute and chronic diseases[38]. Recent studies have suggested that reduced values of FT3 may be involved in the development of frailty and cognitive decline[38, 39], lower circulating FT3/ FT4 ratio represents a sensitive marker of frailty and may be an effective prognostic parameter of higher mortality in hospitalized older patients[31]. In this study, CF group showed the lowest mean level of FT3 compared to the other groups, thus, FT3 may be a useful laboratory parameter in clinical assessment, which can play an important role in identifying vulnerable elderly subjects, especially in the CF group.
Malnutrition and nutritional imbalance are thought to be strongly associated with development of frailty and cognitive impairment due to both the biological and the behavioural effects of diet[40]. The two main pathways to malnutrition in elderly patients are anorexia of aging, and disease-related energy needs after a stressful event[41]. The MNA-SF is validated for diagnosis of malnutrition and prediction of clinical outcomes. In our study, frailty with normal or impaired cognition are associated with poor nutritional status. We also found that malnourished status which was assessed by severe MNA-SF (≤ 7) is associated with an increased risk of non-elective hospital readmission or death in elderly inpatients with CVD.
Study limitations
There are some limitations to this study. We can point out that this is a cross-sectional study with a short term follow-up, and there were only 4 deaths, so the guidance of short-term prognosis focused on the non-elective hospital readmission, but a continued long follow-up study in this population is currently under way in our group, and a randomized controlled clinical trial about multidisciplinary and multifactorial intervention for frailty of elderly inpatients with CVD is also under way. Second, these data were collected from patients at one hospital, thus may not necessarily be directly transferable to patients from different locations, but it can provide more convenient follow-up for these patients. Third, the study only included hospitalized patients, thus, nothing can be inferred about elder people in the community-dwelling from this study. In addition, the small sample size is the main reason for we did not conduct a subgroup analysis of single disease. Fourth, the mean age of the patients in this study was 75 years. For such an old cohort, it is important to consider that a survival bias may be present when applying these finding. Finally, the MMSE or CDT is not a very sensitive means of detecting subtle impairments of cognitive function, and thus in the present study we may have underestimated the proportion of people with cognitive impairment.