This study was intended to identify the factors associated with frailty and thereby develop a prediction model to identify the risk of frailty among institutionalized older adults. In this study, five phenotypes criteria by Fried et al (2001) were used to categorize older adults into frail (cases) and non-frail (controls). [1] With the majority of the studies looking at frailty and its associated factors in community-dwelling aged individuals, the current study was directed at the seldom explored institutionalized elderly.
Multivariate regression analysis showed that seven out of fourteen independent factors showed a statistically significant odds ratio. Among those seven significant factors, comorbidities and smoking status had a positive relationship with frailty. In the present study, the presence of ≥ 3 comorbidities showed an increased probability of frailty. This finding has been supported by a review done by Vetrano DL et al (2019) which states that frailty and multimorbidity are two related conditions in older adults and multimorbidities are major determinants of frailty syndrome. [18] However, their findings are inconclusive regarding the causal association between the two conditions. Hanlon P et al (2018) reported that frailty is significantly associated with multimorbidity and the prevalence rate of frailty increased with the number of multimorbidities. [19]
Modifiable factors like smoking are also significantly associated with frailty, supporting current study results. A review published by Kojima et al (2015) reported smoking as a predictor of worsening frailty status among the elderly. [9] Smoking causes increased levels of inflammatory markers leading to chronic inflammation, muscle wasting and weakness, exhaustion, slow gait speed contributing to frailty component. [6, 20] Amiri and Behnezhad (2019) had done a systematic review and meta-analysis on the relationship between smoking and frailty and reported that the risk ratio of frailty based on smoking was 1.63. The mechanism that has been stated in this regard is that smoking involves substances that increase inflammatory mediators which result in muscle loss, weight loss, and fatigue—all factors engaged in frailty. [21]
Won et al (2020), in their cohort study, have reported that women tended to exhibit a higher prevalence of frailty than men. However, the findings of the current study indicate a negative relationship between female gender and frailty. [22] The reason for this could be due to unequal gender distribution especially after 80 years of age (20 women vs 9 men). A statistically significant association has been found in this study between vegetarian diet and frailty. In this study, dietary nutrition intake was not assessed in detail; only whether the participants consumed a non-vegetarian diet was noted categorically. Huang RY et al (2016) in their multivariate nutrient density model identified associations between low muscle mass and dietary protein intake among community-dwelling older adults. They have reported that the participants in the lowest quartile of total protein density intake were at high risk of sarcopenia, a precursor of frailty. [23]
Frailty and cognition have been negatively associated with this study. Similar results have been shown in a review by Deirdre A Robertson et al (2013). This is explained by the fact that advanced age is a major risk factor for physical and cognitive impairment. [24] In addition to this, institutionalized elderly are more vulnerable and prone have age-related co-morbidities leading to exacerbated homeostatic imbalance, brain aging, and cognitive decline. [25]
Gait speed and grip strength were found to have a statistically significant negative relationship with frailty in this study. Binotto and colleagues performed a systematic analysis of gait speed and physical frailty and found that gait speed is substantially correlated with disability, frailty, cognitive impairment, dependency, mortality, sedentary lifestyle, muscle weakness, poorer health and quality of life, stress, obesity, weight and percentage of body fat and low performance in gait parameters. They had reported considering reduced gait speed as a marker of physical frailty. [26] Bohannon RW advocated the usage grip strength as an indispensable marker for older adults as it was a consistent explanator of concurrent overall strength, upper limb function, bone mineral density, fractures, falls, malnutrition, cognitive impairment, depression, sleep problems, diabetes, multimorbidity, and quality of life. Evidence was also provided for a predictive link between grip strength and all-cause and disease-specific mortality, future function, bone mineral density, fractures, cognition and depression, and problems associated with hospitalization. [27]
Diez-Ruiz et al (2016) identified factors leading to adverse health events among the elderly and aimed to propose a model to identify these elderly in the primary care setting. Age, TUG time (in seconds), and polypharmacy were positively associated with the frailty-related adverse outcome which was expressed using a single model. [28] The results of the univariate analysis in the current study had identified age, TUG, and polypharmacy as the predictors. However, when multivariate analysis was carried out those variables were not identified as the predictors of frailty. The probable reason for this could be the differences in the settings in which these two studies are carried out. Sousa JA et al (2018) have established a prediction model for the development of physical frailty among the oldest old population of primary health care. That model composed of metabolic diseases, dyslipidemias, and several hospitalizations in the last 12 months with the odds ratio of 1.99, 0.32, and 2.50 respectively. [29]
This study has a few limitations. First and foremost, the current study recruited participants from nine old age homes with different levels of assistance and of different environmental dimensions (infrastructure and domestic assistance) which would vary the results. Secondly, physical activity and exhaustion were measured subjectively; objective measures like accelerometer or activity monitors could have been used. Thirdly, socio-demographic and morbidity factors were participant reported, recall bias which is very much prevalent among the elderly would have influenced the results. The model developed can be validated in future studies, incorporating more objective frailty assessment methods like serological or inflammatory biomarkers and inclusion of homogeneous institutions to generalize the results for this population.
Significance of the study
This study identified the factors influencing frailty among institutionalized older adults which would help in decision making about the address of significant factors during the rehabilitation. The prediction model developed could be used at community level screening programs for identifying older adults with the risk of frailty at an earlier stage.