Cystic fibrosis (CF) is an autosomal recessive disease that affects the functioning of various organ and body systems.1 The median estimated survival age for patients with CF has increased substantially over recent decades and is currently estimated at 38 years in most developing countries.2 Factors including early diagnosis, multidisciplinary management in specialised centres, and access to appropriate therapy have contributed to this change.3

The primary clinical consequences of CF are related to respiratory tract impairment, in which thick infected secretions trigger chronic inflammation. Pulmonary function decreases exponentially as patients get older, which results in significant airway obstruction leading to hyperinflation, and air trapping.4 An estimated 90% of patients die due to the progression of pulmonary disease.5 In addition to pulmonary impairment, CF causes significant changes in other organs and systems that can lead to major physical limitations. Compared to the paediatric population, adults with CF show a higher prevalence of skeletal muscle dysfunction, nutritional depletion, diabetes, and depression. Osteoporosis, bone fractures, and joint impairments are common in this group of patients.3

Posture is defined as the balanced arrangement of body structures and is determined by measuring the positioning of the body segments at a particular moment.6 In normal postural alignment, muscles and joints are expected to be in a state of equilibrium that involves the least amount of effort and overload.7 The postural attitude of the hyperinflated thorax can lead to a series of spinal column, shoulder, and pelvic girdle compensations. Spinal column deformities, such as increased thoracic kyphosis and lumbar lordosis, are common in adults with CF.8,9

The biomechanics of the rib cage influence overall body mechanics. Therefore, any respiratory imbalance will result in altered total body posture and balance.10 As lung disease progresses in CF patients, it is possible that hyperinflation and increased effort of breathing causes a general muscle imbalance because of the altered mechanics of respiration.11 It is therefore possible to assume that these changes culminate in a reduction of functional capacity. As this knowledge could be important for planning the most appropriate mode of therapeutic exercise in CF patients we looked to evaluate the correlations within pulmonary function, functional capacity, and posture in adult patients with CF. A secondary aim was to evaluate the correlation between patients’ quality of life (QL) and postural assessment variables.

Of the 38 patients eligible for evaluation, 14 completed the study (Fig. 1). Anthropometric data, pulmonary function, functional capacity, and quality of life questionnaire domains are shown in Table 1. The median distance on the 6MWT was 636.5 m (range: 450–750 m), while the median percentage of Gibbons et al.’s prediction for this distance was 83.3 (67.6–92.3). Data from the postural assessment are presented in Table 2.

Figure 1.

Flow chart showing the different stages of the recruitment process.

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There were only two significant correlations among postural assessment data and the QL questionnaire. These correlations were between the ‘physical’ domain of the CFQ-R and the vertical alignment of the chest (right lateral view) (ρ=-0.74, P<0.01), and between the ‘limitations’ domain of the CFQ-R and the angle of the left hip (ρ=-0.55, P<0.05). Correlations between the postural assessment data and the pulmonary function and functional capacity variables are shown in Table 3 and Fig. 2. The forced expiratory volume in one second (FEV1) and the 6-min walking distance (6MWD) showed statistically significant negative correlations with the vertical alignment of the chest (left lateral view). Statistically significant positive correlations were noted between the total lung capacity (TLC) and the vertical alignment of the chest (right lateral view) and between airway resistance (Raw) and the vertical alignment of the chest (left lateral view).

Figure 2.

Correlation between the left lateral view of the vertical alignment of the chest and the 6-min walking distance (6MWT) (ρ=−0.65, P<0.01). The correlation was determined using Spearman's correlation test.

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The posture assessment in a standing position has been increasingly used in clinical practice, as the body alignment observation can be used to plan and monitor physical therapy treatments.

In the present study, seven out of ten angular photographic assessment values from the PAS protocol were inconsistent with the normal values described by Ferreira et al.14 There are several mechanisms, such as lower bone mineralisation, that can justify these postural changes in CF patients. In these patients, bone fractures are relatively common, and respiratory muscles undergo increased stress because of pulmonary hyperinflation.9 Compared to data from patients with chronic obstructive pulmonary disease21, the results of the present study show a similar angular value in the horizontal alignment of the head (2.80 and 2.90, respectively). Despite the age differences of patients, both diseases have a similar basic pathophysiological mechanism (air trapping), which justifies a comparative analysis of the data. The misalignment of the head can be partially explained by the elevation of the ipsilateral acromion, which may be caused by increased tension in the shoulder muscles.22 In obstructive pulmonary diseases, this modification may be caused by changes in pulmonary mechanics.

In the present study, the statistically significant correlations of the pulmonary function variables were observed with the angular value of the vertical alignment of the chest, both in the right and left lateral views. The angular value of the vertical alignment of the chest has the acromion and greater trochanter as bone references. The shortening of the accessory muscles (especially the pectoral and sternocleidomastoid) and abdominal muscles may justify these correlations. Interestingly, Dunk et al.23 observed that the sagittal plane, from which this parameter is extracted, best reflects the postural clinical outcome when the angular sagittal plane values differ from zero; in the frontal plane, the values tend to be zero (symmetry).

When evaluating the static lung volumes and the Raw in CF, the most striking phenomenon is the air trapping that is the consequence of a delayed alveolar emptying. The TLC can also be increased due to the loss of elastic recoil. Another mechanism that can cause the increase in TLC is cutting-off the expiratory time; this causes inspiration begins before air is fully eliminated from the lungs.24 These findings may explain the statistically significant positive correlations among TLC, Raw, and changes in the vertical alignment of the chest.

Another focus was the relationship between functional capacity and body posture. Simpler and less expensive tests such as the 6MWT have been used for assessing exercise tolerance in adult patients with CF, since the distance achieved in the walking test provides an estimate of individual response to maximum incremental exercise.25 Our study showed a significant negative correlation between the 6MWD and the vertical alignment of the chest in the postural assessment. This correlation can be explained by the mechanisms of loss of stability of the chest wall as result of hyperinflation, which in turn leads to a poor functional capacity.

There is evidence that intolerance to exercise in patients with CF is multifactorial, depending on pulmonary function, nutritional state, and adherence to treatment, and other factors.25 In these patients, decreased exercise tolerance limits the performance of daily activities and is associated with lower survival.26 In a study conducted on 88 patients with CF who were at least 10 years old, Ziegler et al.27 found that 15% of the patients presented with oxygen desaturation in the 6MWT. According to our results, it is possible that postural changes may also contribute to poor performance during exercise. Postural deformities cause an imbalance of the muscular system that prevents the normal movement.9 This suggests that conditioning programs along with postural re-education can play a positive role in the limited exercise capacity of CF patients.28,29

Evaluations of QL are important for planning and monitoring treatment and for the identification of predictive factors of QL.30 Regarding the CFQ-R, the results of the present study corroborate those described by Cohen et al.13, who assessed quality of life in patients, including adults, with CF. Both studies showed that the worst domain was the ‘social’ domain, which may be related to the negative perception of patients regarding their performance and social inclusion. In the present study, it is also worth noting that inverses and significant correlations were only observed between two CFQ-R domains (‘physical’ and ‘limitations’) and the postural assessment. The association between functional performance and QL is well established in the literature. Because there was an association between posture and functional performance in our study, the postural abnormalities might have played a direct or indirect role in the health-related quality of life of these individuals. New studies are necessary to evaluate the effects of corrective postural exercises on the QL of patients with CF and in other chronic respiratory diseases.

A critical analysis of the results and their limitations is appropriate. The present study was conducted on a relatively small number of individuals, and no control group was used. Despise these limitations, this is the first study to evaluate the relationship between postural assessment results and lung function parameters in adult patients with CF. Because there are few published studies regarding posture in this group of patients, we believe that our results will make an important contribution to the field. Future studies may reach comprehensive results using more detailed statistical analysis by increasing the number of adult CF patients, control group and longitudinal follow up.

In conclusion, the present study shows that adult patients with CF have significant postural abnormalities. The vertical misalignment of the chest correlates to changes in the lung function, quality of life and functional capacity variables.

The authors have no conflicts of interest to declare.