Date Published: October 1, 2017
Publisher: JKL International LLC
Author(s): Ilia Stambler.
It is becoming increasingly clear that in order to accomplish healthy longevity for the population, there is an urgent need for the research and development of effective therapies against degenerative aging processes underlying major aging-related diseases, including heart disease, neurodegenerative diseases, type 2 diabetes, cancer, pulmonary obstructive diseases, as well as aging-related complications and susceptibilities of infectious communicable diseases. Yet, an important incentive for the research and development of such therapies appears to be the development of clinically applicable and scientifically grounded definitions and criteria for the multifactorial degenerative aging process (or “senility” using the existing ICD category), underlying those diseases, as well as for the safety and effectiveness of interventions against it. Such generally agreed definitions and criteria are currently absent. The devising of such criteria is important not only for the sake of their scientific value and their utility for the development of therapeutic solutions for the aging population, but also to comply with and implement major existing national and international programmatic and regulatory requirements. Some methodological suggestions and potential pitfalls for the development of such criteria are examined.
“Senility,” tantamount to degenerative aging, is already a part of the current ICD-10 listing, carrying the code R54. The “senility” code is also applicable to “old age,” “senescence” and “senile asthenia” as well as “senile debility,” while excluding “senile psychosis” (F03) (http://apps.who.int/classifications/icd10/browse/2016/en#R54). In the draft ICD-11 version (to be finalized by 2018, http://www.who.int/classifications/icd/revision/en/), the code MJ43 refers to “Old age,” synonymous with “senescence” and “senile debility,” while excluding “senile dementia” (code AA60) (http://apps.who.int/classifications/icd11/browse/l-m/en#/http://id.who.int/icd/entity/835503193). The nearly 40 associated “index terms” in the ICD-11 draft also include “ageing” itself, “senility” (n.o.s.), “senile degeneration,” “senile decay,” “frailty of old age” and others. Still, the current definitions, such as “senility” defined in an ICD-11 draft as “failure of function of otherwise normal physiological mental or physical process(es) by aging. Not to be used under the age of 70 years” seem to be rather deficient in terms of their clinical utility. Furthermore, a comprehensive, scientifically and clinically usable list of general symptoms for “senility” in the ICD is still lacking. This may be the reason why “senility” has been commonly considered a “garbage code,” e.g. in the Global Burden of Disease (GBD) studies [8,9]. The reason “senility” has been considered a “garbage code” is likely because there have been no reliable, clinically applicable and scientifically grounded criteria for diagnosis of “senility” or of “senile degeneration.” Consequently, there could be no official case finding lists. Hence, in order to successfully use this code in practice, it appears to be necessary to be able to develop formal and measurable, biomarkers-based and function-based diagnostic criteria for “senility” or “senile degeneration,” as well as measurable agreed means to test the effectiveness of interventions against this condition.
Notably, “treatable medical condition” does not necessarily mean a “disease.” “Medical condition” in relation to aging may as well refer to “geriatric syndrome” as is commonly used by geriatricians to define aging-related frailty (indicative of “high risk for a number of adverse health outcomes, and mortality” ), as well as delirium, falls, and incontinence. However, in order to arrive at reliable diagnostic definitions, the common functional frailty assessments may need to be supplemented in a larger scope with assessments of biomarkers of the aging process, in correlation with each other, thus reinforcing the diagnostic and predictive capacity of the combined functional and biological indicators. Currently, functional assessments dominate the evaluations of frailty (http://frailty.net/diagnostic-tools/). For example, in the widely used “Study of Osteoporotic Fractures” (SOF) frailty index, there are 3 main diagnostic parameters: 1) “Weight loss,” 2) “Inability to rise from a chair,” and 3) “Poor energy” as identified by an answer “yes” or “no” to the question “Do you feel full of energy?” on the Geriatric Depression Scale . And in the even more widely used “Cardiovascular Health Study” (CHS) frailty index, the 5 parameters are: 1) “Shrinking” as shown by an unintentional weight loss, 2) “Weakness” as shown by a maximal grip strength, 3) “Poor energy” as determined by an answer to the question “Do you feel full of energy?” 4) “Slowness” as indicated by an average walk speed, and 5) “Low physical activity level” as identified by a Physical Activity Scale for the Elderly (PASE) score in the lowest quintile . It may be seen that biological markers of aging are assigned little significance in such scores.
This work has argued that the devising of clinical criteria for degenerative aging or “senility” (to use the current ICD term) is important not just for the sake of their scientific interest, or their utility for developing therapeutic solutions for the aging population, but also to comply with and implement major national and international programmatic and regulatory requirements. Yet several critical methodological challenges may arise in developing commonly acceptable diagnostic definitions and criteria for degenerative aging.