Co-morbidities in chronic respiratory patients: limitations or opportunities for caring?
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- Crisafulli, E., Venturelli, E., Iattoni, A. et al. J Med Pers (2011) 9: 99. doi:10.1007/s12682-011-0099-1
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In a population of chronic respiratory patients, a new subset with clinical complexity and with multiple coexisting organ failure and diseases is rapidly growing. Mainly due to the aging process, the associated frailty—not strictly related to the patient’s age—consists in a progressive and physiologic decline in multiple body systems leading to a substantial loss of functions and physiologic reserve. It is commonly acquainted that frailty, co-morbidities (several medical conditions associated) and disability (decline in physical functions) overlap each other: both frailty and co-morbidities can predict physical disability, whereas disability per se may exacerbate frailty and co-morbidities. As specific interventions (as rehabilitation) targeting at the physical activity, the old population have been shown to improve physical function and have a benefit along the full spectrum of health status. However, there is a substantial need for a multidimensional and personalized care approach: patient’s complexity, in fact, may play a role in determining the patient’s response to treatment. In particular, each disease as a single entity might reduce the response to treatment, depending on its effect on body functions and target therapies. Notwithstanding, the clinical complexity of these patients and the presence of several co-morbidities do not preclude per se the application and the effectiveness of a comprehensive rehabilitation program targeted to the individual’s needs.
Definition of frailty
Clinical syndrome in which three or more of the following criteria are present
Unintentional weight loss (10 lbs in past year)
Self-reported exhaustion (fatigue)
Weakness (grip strength)
Slow walking speed
Balance and gait abnormalities
Evaluation of these patients is more likely to include specific physical (muscle/body weakness, reduction of walking tolerance and immobility) and social (community isolation and institutionalization) outcomes among those measurements able to describe the individual’s health status [3, 4].
Although frailty is more prevalent in older people, this clinical condition may be an independent physiologic process involving multiple organs, but not strictly related to the patient’s age . Indeed, several medical conditions which frequently coexist in older population, such as chronic heart failure, systemic hypertension, or diabetes, develop early during the lifetime and even share patho-physiologic mechanisms, thus directly influencing the patient’s health , and speeding up the individual’s decline in physical functions (=disability) .
Patients suffering from chronic respiratory diseases commonly refer both frailty and disability; in particular, those with chronic obstructive pulmonary disease (COPD) are more likely to be affected by multiple coexisting extra-pulmonary diseases that further contribute to loss in function .
Overall, it is commonly acquainted that frailty, co-morbidities, and disability overlap each other: both frailty and co-morbidities can predict physical disability, whereas disability per se may exacerbate frailty and co-morbidities [1, 2]. Moreover, the chronic complex co-morbidities may contribute to the development of frailty [4, 9–11].
The clinical disability of these complex patients due to co-morbidities can negatively predict the patient’s health status [10, 12] and their social costs [13, 14] mainly due to a reduction of physical function and to a loss of independence and participation. Incident falls and frequent hospitalisations are, therefore, hallmarks of severity, and further identify the need for prolonged assistance up to long-term nursing-home care options [15–18].
Opportunities for caring
In the elderly population, most studies have separately focused on the general problem of frailty and its treatment in different situations, while in the community [19–22], following hospital discharge  or during programs of falling prevention [24–26].
No previous research has been developed to specifically target at reversing any factor included in this complex syndrome of older patients: indeed, several attempts have been made only to improve specific clinical outcomes. Therefore, changing the focus on to a more global treatment approach, a multidimensional and personalized care aimed both at meeting all individual’s needs and at increasing the residual physical capacities is more likely to give health gain to these complex patients. Thus, rehabilitation and physical interventions become treatments of choice in elderly . Indeed, muscle mass and strength spontaneously decrease with age, and the trend is even more pronounced in the frailty syndrome , especially in those individuals reporting COPD .
Several studies have already shown that exercise is beneficial even in the old population along the full spectrum of health status [29–31]. Specific interventions targeting at the physical activity in elderly people have been shown to improve physical function. A recent systematic review aimed at assessing the effectiveness of community-based multi-factorial interventions to preserve the individual’s independence found that improvement of physical function was greater in the treated than in the untreated elderly patients .
Therefore, it seems to be mandatory to ask ourselves whether a care achievement and perspective is likely when using a non-pharmacological intervention aimed at maximizing the compromised function and at preventing any further decline in this population. The key question is whether the comprehensive rehabilitation process is also applicable in old, frail and, disable patients with complex co-morbidities.
So far, lower extremity and high-intensity progressive resistance exercise training has been shown to be feasible and effective even in very old (mean age >85 years) residents in a long-term care facility; improvements in muscle strength and dimension (=increase in the cross-sectional thigh-muscle area), in gait velocity and in stair climbing were selectively reported in those subjects who underwent training .
More recently, in a prospective case–control study aimed at improving physical abilities (balance, muscle strength, ability to transfer from one position to another, and mobility taken over 6 months) in 75-year physically frail and living at home patients , authors have demonstrated a slower progression of functional decline over 1 year in the participants than in the control group. Notwithstanding, benefits were only observed in those patients with moderate (but not with severe) frail condition.
These clinical data are repeatedly reported in patients with chronic respiratory diseases. Indeed, Baltzan et al. reported success of rehabilitation in a population of patients suffering from chronic obstructive pulmonary disease (COPD) with less than or greater than 80 years, but with a similar number of other coexisting chronic medical diseases. They have applied an inpatients pulmonary rehabilitation (PR) program which resulted in similar beneficial effects in terms of walking capacity (6-min walk distance test, 6MWD), stair climbing and Global Functional Score independent on the age class .
Functional aspects have been retrospectively investigated in a large population (n = 2962) of old COPD patients with coexisting cardiovascular, metabolic and skeletal diseases admitted to a PR program ; authors aimed at evaluating whether any single or aggregated co-morbidities, as assessed by the Charlson index (which assigns to each disease a score that is proportional to the disease-related risk of death ), may have influenced the outcomes following the PR course.
Basically, they found that some co-morbidities associated with COPD may significantly impact some outcomes at program discharge; indeed, the proportion of patients showing a pre-defined improvement in perceived breathlessness (reduction of 1 point at the modified Medical Research Council-MRC dyspnoea scale)  and in health-related quality of life (reduction of 4 points at the St. George’s Respiratory Questionnaire-SGRQ)  that exceed the minimum clinically important difference (MCID)  was different across the categories of co-morbidities (0, 1 or ≥2) associated with COPD, being lower in the more complex patients. This was not the case of walking tolerance in terms of capacity to improve 54 m over the baseline level at the 6MWD . Interestingly, the same study also showed that the presence of metabolic syndrome (systemic hypertension, diabetes, and dyslipidemia) was inversely related to the improvement in exercise performance, whereas chronic heart failure and/or coronary heart disease indirectly predicted the improvement in perceived quality of life .
Another group of researchers in Italy documented similar and consistent results in complex COPD out-patients . At the end of 8-week physical training, authors have found a significant improvement in 6MWD and SGRQ in all patients except for those with associated cardiovascular disease, even if in stable state. However, in contrast to the findings by Crisafulli et al. , the presence of coexisting cardiovascular diseases was not a significant predictor of poor response to pulmonary rehabilitation, although co-morbidities per se reduced the likelihood of reaching the MCID threshold for both 6MWT and SGRQ.
In another multicentre study at four Italian hospitals in 316 selected moderate and severe COPD out-patients, the potential effect of co-morbidities on the rehabilitation outcomes was prospectively evaluated .
The results indicated that there was no association between the number and type of co-morbidities and the effectiveness of the pulmonary rehabilitation program. In this sample population of out-patients, only the presence of osteoporosis was inversely related as a true negative predictor of change in walking performance. This was probably linked to specific factors such as bone frailty, muscle weakness, and/or steroids-related myopathy, which typically occur in COPD patients even at this setting.
Frailty related to osteoporosis and bone diseases has been investigated earlier in a study by Di Fazio  and colleagues on more than 700 elderly patients with pre-existing Parkinson’s disease or osteoarthritis and submitted to physical rehabilitation after an acute stroke event. In this study, authors showed that the main determinant of poor physical recovery was the association of osteoporosis and arthrosis as disabling conditions, rather than the effect of each single chronic disease, independent of age, cognitive or functional status at admission.
In conclusion, several factors may influence the health status and prognosis of elderly, frail, and complex patients.
In the population of chronic respiratory patients, co-morbidities have to be considered a hallmark of individual’s frailty, which need to be adequately screened and assessed. Despite preliminary experience are quite promising and convincing, still there is a substantial need for a multidimensional and personalized care aimed both at increasing the residual physical capacities in these patients. Indeed, exhaustive health-specific outcomes are still welcomed to capture favorable change after a comprehensive intervention.
Although rehabilitation and physical interventions including muscle training have to be considered intriguing opportunities to this achievement, the patient’s complexity may play a role in determining the patient’s response to treatment. In particular, each disease as a single entity might reduce the response to treatment, depending on its effect on body functions and target therapies. Notwithstanding, the complexity of these patients and the presence of several and associated co-morbidities do not preclude per se the application and the effectiveness of a comprehensive rehabilitation program targeted to the individual’s needs, that is really an opportunity for caring. It is likely that a complex physical approach may act forward by decreasing disability and even backward by reducing the burden of the disease which is know to be particularly relevant in those individuals suffering from COPD.
Conflict of interest
The authors declare that they have no conflict of interest.