**Abstract**

Geriatrics is an applied science as its practice is an art of medicine. As a scientific discipline, there exists a potential race for measurements. Frailty stands as among poorly defined concepts in geriatric medicine. There are philosophical, circumstantial, and practical justifications behind this rather seemingly *clinical tragedy*. This chapter contributes toward reliability and validity aspects of currently applied frailty scales and indicators across different population base. It acknowledges the contribution of Fried's frailty scale. It also describes different frailty scales and indicators tested in America, Europe, and Asia. Lastly, the chapter contrasts the popular belief behind applications of Cronbach's α coefficient of test scores for reliability assessment in clinical research. Other research gaps are also highlighted including merging clinical research findings in geriatrics with psychosocial aspects under the emerging field of geropsychology. It also proposes a solution for usage in future studies that aim at assessing reliability of test scores in clinical and biomedical sciences.

**Keywords:** frailty, reliability, validity, multimorbidity, index, scale

## **1. Introduction**

Geriatric medicine is a relatively younger sub-specialty of medicine. Unlike fields like general internal medicine or surgery, that are known to have existed since antiquity, geriatrics has gained significant popularity, in orthodox medical practice, around the second half of the twentieth century. Geriatrics is *an applied science* just as its practice is *an art* of medicine. For that matter, there exists a potential race for measurements. It follows logic therefore that for geriatric medical conditions and practice to be acceptable among scientists, it needs unified codes that are measurable. This chapter will provide basic aspects associated with measuring variables that are customarily prevalent in geriatric wards and corridors throughout the world. Specifically, it analyzes the reliability and validity of different scales of the commonest concept of *frailty* among senior citizens the world over.

The clinical characterization, of modern geriatric medicine, owes much to the pioneering work, of Professor Bernard Isaacs back in the 1960s. It was Isaacs who is credited in public literature, to have coined the term "*geriatric giants*," in common usage, to geriatricians the world over to date [1]. Simply stated, he referred "geriatric giants" to conditions of *immobility*, *instability*, *incontinence*, and *impaired memory/ intellect* that are relatively common, on statistical grounds, among senior citizens of any human society [1]. From 1960s onward, the conditions characterizing *geriatric giants* have changed several times, and currently used mainly among scholars and clinicians alike, in its modified form, as per Professor Mary Tinetti's keynote address of *Geriatric 5Ms,* at the Canadian Geriatric Society conference, back in April 2017 [2]. She addressed the Geriatric 5Ms to comprise the *Mobility*, *Mind*, *Medications*, *Multi-complexity*, and *Matters* most [2]. It must be understood that most of this characterization refers to measurable constructs that defines core aspects of geriatric medical research and practice, initially coined as *geriatric giants* by Isaacs in 1965.

There exists a lot of confusion in geriatric medicine to date, regarding the measurable construct of *geriatric giants* [3–7]. Part of this confusion has basis from failure to achieve standard definitions from its components. This is because, in almost all cases, disease conditions among senior citizens, unlike other groups in the population pyramid, tend to present *atypically* on clinical grounds. Whereas the exact cause of this trend among senior citizens is still ill understood, there exists evidence for a common pathway, originating from different organ systems, in etiopathogenesis of diseases in the elderly. Moreover, quite often there is also a disconnect between the original site of *malice* and the clinical presentations for symptoms and signs of pathologic conditions thereafter. The immediate effect of this rather anomalous conundrum is the rather *bizarre presentations* of most common clinical conditions, seen among senior citizens, as well as recorded in their morbidity and mortality statistics throughout the world.

Atypical presentation in the elderly can be exemplified, say by a Nonagenarian lady, presenting to the emergency department of a typical hospital, with symptoms and signs suggestive of acute confusional state like delirium, caused by *Escherichia coli* infection in her urinary tract. As it is commonly the case, once her bladder cystitis/urethritis is treated, using relatively simple treatment pathways, the acute confusional state disappears. The observation given, justifies not only the atypical nature of presentation, to most geriatric illnesses, but also the multiple organosystemic involvement, in their pathogenesis. Besides, growing characterization of emotional, social, and cognitive aspects of aging is paramount in modern clinical practice. There are several theories and postulates that endeavor to link the interplay of the mind (and the central nervous system) in multisystemic etiopathogenesis of Geriatric 5Ms. The theories and postulates have evolved into a new sub-specialty named geropsychology. The details of which will be discussed further in the discussion section. However, to the betterment of science, there exists palpable evidence that probably the so-called *Geriatric 5Ms* has achieved a unified goal of standardizing the measurable construct of *geriatric giants*. It is on this basis that this chapter finds its pivot, on the attributable last aspect of *Matters most*, referred to as *Frailty*.

Frailty is a poorly defined syndrome almost exclusively confined to the elderly population. There are dozens of descriptions given for frailty [8–15]. All of them were made for specified frameworks of interest by their original authors. On pedagogic sense, none could be used systematically, without a pinch of doubt, to any destitute clinician/researcher. However, out of dozens of frailty definitions available, the one proposed by Fried and colleagues in Cardiovascular Health Study Collaborative Research Group back in 2001 [13] is the most widely applied framework by clinicians/researchers in bio-gerontologists the world over. The underlying scientific framework for applying frailty syndrome to be discussed in this chapter has taken into account the famous fact derived by Sir George Box's seminal paper back in 1978 that *all models are wrong but some are useful* [16] in its philosophical sense. It is neither the intention of this chapter nor anywhere in the mind of its author to market the Cardiovascular Health Study Collaborative Research Group's

*Reliability and Validity of Clinicopathological Features Associated with Frailty Syndrome… DOI: http://dx.doi.org/10.5772/intechopen.93499*

frailty postulate. Rather, and I do believe it to be safe, the plan is to sparingly appreciate strengths and weaknesses of some of these useful concepts, via estimation of their internal consistency and content validity in each of them. Thus, this chapter will guide the reader through reliability and validity aspects of clinicopathological features associated with frailty syndrome in senior citizens.
