Elsevier

Physiotherapy

Volume 102, Issue 2, June 2016, Pages 202-209
Physiotherapy

Decreased health-related physical fitness in adults with ankylosing spondylitis: a cross-sectional controlled study

https://doi.org/10.1016/j.physio.2015.05.003Get rights and content

Abstract

Objectives

(1) Assess the health-related physical fitness of adults with ankylosing spondylitis (AS) and compare these to the general population, and (2) examine the relationships between physical fitness and condition-specific outcomes.

Design

Cross-sectional, controlled study.

Setting

Exercise research laboratory.

Participants

Thirty-nine adults with AS (32 men, 7 women) and 39 age- and gender-matched controls.

Intervention

Comprehensive physical fitness assessment, and completion of questionnaires assessing disease activity, physical function and quality-of-life.

Main outcome measures

Body composition was assessed by bio-impedance analysis. Flexibility was measured with the Bath AS Metrology Index (BASMI). Cardiorespiratory fitness was assessed by submaximal treadmill test with breath-by-breath gas analysis and heart rate monitoring. Muscular strength and endurance were measured by isokinetic dynamometry of concentric knee flexion/extension.

Results

The AS group demonstrated significantly lower cardiorespiratory fitness [mean difference −1.3 mL min−1 kg−1 (95% CI −1.1 to −1.4)], flexibility [0.4 BASMI units (0.2 to 0.7)], muscular strength [−31.6 peak torque per body weight dominant knee extension (−56.1 to −7.1)], and increased body fat [0.4% (0.0 to 1.2)] compared to population controls (p < .05). There were significant associations between each fitness component and physical function (p < .05). Higher aerobic capacity was significantly associated with improved quality-of-life. Fitness was not significantly associated with disease activity.

Conclusion

Adults with AS have significantly reduced health-related physical fitness compared to population controls. Decreased body fat, and higher aerobic capacity, muscular fitness and flexibility are significantly associated with improved function. These findings have implications for clinicians assessing adults with AS, and for targeted-exercise prescription in this cohort.

Introduction

Ankylosing spondylitis (AS) is a chronic rheumatic condition characterised by inflammatory back pain and stiffness [1]. The European prevalence of AS is 24 per 10 000, with an estimated 1.30–1.56 million cases [2]. Males are more commonly affected than females in a ratio of approximately 2 to 1 [1]. Accompanying extra-articular features of AS may include uveitis, osteoporosis, bowel disease, and cardiac, pulmonary, skin (psoriasis) and kidney involvement [3]. It is associated with decreased work productivity and lower health-related quality of life (QoL) [4], [5].

Physical fitness may be generally defined as a set of attributes that relate to the ability to perform physical activity, and the capacity to reduce the risk for developing diseases associated with physical inactivity [6]. These attributes are generally divided into health-related components or skill-related components (i.e. agility, balance, coordination, speed, power and reaction time). The health-related components include: (1) body composition, (2) cardiorespiratory capacity, (3) muscular strength and endurance, and (4) flexibility.

In AS cohorts restrictions in joint mobility, particularly of the spine, are well documented [7]. With the recognition of increased risk of cardiovascular disease in AS, cardiorespiratory fitness has more recently been explored and a reduction in aerobic capacity among adults with AS has been reported [8], [9], [10], [11], [12]. Cachexia, the accelerated loss of skeletal muscle in the context of a chronic inflammatory response, is a common feature of other rheumatic conditions, however body composition studies have not consistently demonstrated cachexia in AS populations [13], [14], [15], [16], [17].

Therapeutic exercise is recognised as a key component in the management of AS [18]; short- and long-term improvements in condition-related symptoms and general fitness have been demonstrated [19], [20]. Exercise-based interventions have traditionally focused on flexibility and spinal mobility [19]. Multimodal exercise programmes, integrating aerobic and strength components, have shown additional beneficial effects on physical fitness [21], [22], [23], [24]. The optimal exercise programme remains unclear [19], [20]. A comprehensive profiling of the health-related physical fitness of adults with AS will assist researchers and health-care practitioners in designing more comprehensive, targeted exercise interventions.

The aims of this study were to: (1) assess the health-related physical fitness of adults with AS and compare these to the general population, and (2) examine the relationship between physical fitness and condition-specific outcomes.

Section snippets

Design

This was a cross-sectional, controlled study undertaken between May 2013 and March 2014. Approval for the study was granted by the St. James's Hospital Research Ethics Committee. The STROBE guidelines for reporting observational studies were followed in drafting this report [25].

Participants & centre

A convenience sample of adults with AS was recruited from a dedicated AS clinic in the Rheumatology Department of St. James's Hospital, Dublin. An invitation to participate in the study and an information leaflet were

Participant recruitment

Of the 76 adults attending the rheumatology clinic over the recruitment period, 58 (76%) were potentially eligible for inclusion in the study. Thirty-nine subjects (32 men, 7 women) accepted the invitation to be included in the study. Non-participants (14 men, 5 women) had a mean age of 39.9 years (SD 10.6) and were not significantly different to those entering the study across age and gender variables (p > .05). Thirty-nine age- and gender-matched population controls were recruited. Participant

Discussion

The first aim of this study was to assess the health-related physical fitness of adults with AS, and compare these to the general population. The AS group demonstrated significantly lower cardiorespiratory fitness, flexibility, muscular strength and endurance, and increased body fat, compared to age- and gender-matched population controls. The second aim of this study was to investigate the association between physical fitness components and AS-related outcomes. There were significant moderate

Conclusions

Adults with AS demonstrated significantly reduced cardiorespiratory fitness, flexibility, muscular strength and endurance, and significantly increased body fat, compared to age- and gender-matched population controls. All of these components of physical fitness were associated with physical function. Additionally, aerobic capacity was associated with QoL. These findings have significant implications for clinicians assessing adults with AS, and in targeted-exercise prescription in this cohort.

Acknowledgements

We wish to thank the Centre for Support and Training in Analysis and Research (CSTAR) for their consultation and advice on data analysis.
Ethical approval: Approval for this study was granted by the St. James's Hospital Research Ethics Committee.
Funding: TOD reports receipt of a studentship grant from Trinity College Dublin during the conduct of the study.
Conflict of interest: The authors report no conflicts of interest.

References (49)

  • O. Ozdem Yr et al.

    Reduced vital capacity leads to exercise intolerance in patients with ankylosing spondylitis

    Eur J Phys Rehabil Med

    (2011)
  • L.F. Hsieh et al.

    Aerobic capacity and its correlates in patients with ankylosing spondylitis

    Int J Rheum Dis

    (2014)
  • S. Halvorsen et al.

    Physical fitness in patients with ankylosing spondylitis: comparison with population controls

    Phys Ther

    (2012)
  • S. Mathieu et al.

    Cardiovascular events in ankylosing spondylitis. An updated meta-analysis

    Semin Arthritis Rheum

    (2014)
  • S. Marcora et al.

    Preliminary evidence for cachexia in patients with well-established ankylosing spondylitis

    Rheumatology (Oxford)

    (2006)
  • F.P. Dos Santos et al.

    Whole body and regional bone mineral density in ankylosing spondylitis

    J Rheumatol

    (2001)
  • E. Toussirot et al.

    Bone density, ultrasound measurements and body composition in early ankylosing spondylitis

    Rheumatology (Oxford)

    (2001)
  • I. Sari et al.

    Body composition, insulin, and leptin levels in patients with ankylosing spondylitis

    Clin Rheumatol

    (2007)
  • G. Plasqui et al.

    Physical activity and body composition in patients with ankylosing spondylitis

    Arthritis Care Res (Hoboken)

    (2012)
  • J. Braun et al.

    2010 update of the ASAS/EULAR recommendations for the management of ankylosing spondylitis

    Ann Rheum Dis

    (2011)
  • T. O’Dwyer et al.

    Exercise therapy for spondyloarthritis: a systematic review

    Rheumatol Int

    (2014)
  • H. Dagfinrud et al.

    Physiotherapy interventions for ankylosing spondylitis

    Cochrane Database Syst Rev

    (2008)
  • G. Ince et al.

    Effects of a multimodal exercise program for people with ankylosing spondylitis

    Phys Ther

    (2006)
  • H. Karapolat et al.

    Are swimming or aerobic exercise better than conventional exercise in ankylosing spondylitis patients? A randomized controlled study

    Eur J Phys Rehabil Med

    (2009)
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