Chronic Microaspiration and Frailty: A Geriatric Smoking Gun?

Discussion

All 3 patients met the Fried criteria for frailty, although there were several confounding issues.² All 3 patients lost between 20 and 25 lb; all had clearly become weaker according to nursing and rehabilitation staff (although none were formally assessed for grip strength); and all had clear declines in their activity level. Patient 3 had a clear decrement in gait speed, but patient 1 had severe gait impairment due to Parkinson disease (although his gait in therapy had clearly worsened). Patient 2 was paraparetic and unable to ambulate. There also was evidence of limited biomarkers of systemic inflammation; all 3 patients’ albumin had decreased, and patients 2 and 3 had significant decrease in hemoglobin; but these commonplace clinical biomarkers are obviously multifactorially determined. We have limited data on our patients’ CRP levels; serial levels would have been more specific for systemic inflammation but were infrequently performed on the patients.

Multimorbidity and medical complexity are more the rule than the exception in frail geriatric patients,and it is difficult to separate the role of microaspiration from other confounding conditions that might have contributed to these patients’ evolving systemic inflammation and frailty.¹⁸ It might be argued that the decline for patient 1 was related to the underlying Parkinson disease (a progressive neurologic illness in which systemic inflammation has been reported), or that the decline of patient 2 was related to the worsening pressure injuries rather than to covert microaspiration.¹⁹ However, the TBIs for patient 2 and the schizophrenia for patient 3 would not be expected to be associated with frailty or with systemic inflammation. Furthermore, the frailty symptoms of patient 3 and inflammatory biomarkers improved after the risperidone, which was likely responsible for his microaspiration, was discontinued. All 3 patients were at risk for oropharyngeal dysphagia (antipsychotic medication is clearly associated with dysphagia²⁰); patient 2 demonstrated pathologic evidence of DAB at autopsy.

There is evolving evidence that chronic systemic inflammation and immune activation are key mechanisms in the pathogenesis of frailty.^4-6 It is known that elevated serum levels of proinflammatory cytokines, including tumor necrosis factor-α, interleukin-6, and CRP are directly associated with frailty and are inversely associated with levels of albumin, hemoglobin, insulin-like growth factor-1, and several micronutrients in frail individuals.^4-7,21,22 Chronic inflammation contributes to the pathophysiology of frailty through detrimental effects on a broad range of systems, including the musculoskeletal, endocrine, and hematopoietic systems and through nutritional dysregulation.^2,4,23 These changes may lead to further deleterious effects, creating a downward spiral of worsening frailty. For example, it seems likely that our patients’ progressive weakness further compromised airway protection, creating a vicious cycle of worsening microaspiration and chronic inflammation.

Conclusions

To date, the role of chronic microaspiration and DAB in chronic systemic inflammation or in frailty has not been explored. Given the prevalence of microaspiration in nursing home residents and the devastating consequences of frailty, though, this seems to be a crucial area of investigation. It is equally crucial for long-term care staff, both providers and nursing staff, to have a heightened awareness of covert microaspiration and a low threshold for referral to speech pathology for further investigation. Staff also should be aware of the utility of the Fried criteria to improve identification of frailty in general. It is probable that covert microaspiration will prove to be an important part of the differential diagnosis of frailty.