Hydrotherapy – the ‘Biologic’ in the Non-Pharmacological Management of Axial Spondyloarthritis?

There is published research investigating the effect of a range of aquatic interventions on axSpA.  Systematic review and meta-analysis has found aquatic physiotherapy can statistically significantly improve pain and disease activity (6) and is an appropriate alternative when land-based exercise is not well tolerated (7).  Systematic review of both land and aquatic exercise in AS supports an individualised multimodal approach to exercise prescription (8).  This has been further supported by systematic review and meta-analysis of the effectiveness of physiotherapy including aquatic physio in axSpA (9) with specific management approaches having different benefits (10).

Individual studies have found aquatic physiotherapy improves pain, metrology, (11) disease activity and quality of life in axSpA, with improvement in quality of life statistically significantly greater than compared with land based exercise (12).  In addition aquatic physio has been found to improve pain, stiffness, disease activity and function when combined with a stretching programme (13), with improvement in pain, function, metrology and disease activity seen at 6-month follow up when combined with spa therapy (14). Aquatic physiotherapy has been shown to improve pulmonary function in AS (15) with potential additive benefits compared to land based training (16), while Gunay 2018 (17) reported performing balance training in warm water had positive effects on stability compared with land based training.

Qualitative research in spondyloarthritis has found aquatic physiotherapy to have a wide range of reported benefits including: energy, sleep, cognitive function, ability to work and participation in daily life (18).  Patients also reported that exercising in warm water had an important positive impact on wellbeing while having an experienced instructor had an important role in coaching and reassuring.  A national survey of NHS hydrotherapy provision (19) found patients reported similar benefits seen in research trials and a postcode lottery in accessing services due to pool closures.

 Aquatic physiotherapy is commonly seen as costly and is a target for making savings through hydrotherapy pool closures and gradual disinvestment in facilities, however aquatic physiotherapy has been found to be cost-effective for a range of musculoskeletal disorders (20).  Lineker 2000 (21) found that access reduced use of healthcare and reliance on others, while patients have reported reduced use of analgesia and NSAID’s (21) (22).

 Next steps

To optimise the role of aquatic physiotherapy in the management of axSpA further quality research with larger sample sizes is required with a focus on the dose, and content of the aquatic exercise programme.  There may be differences in response with different groups of patients: for example radiographic and non-radiographic disease or with the level of disease activity.  Research investigating these cohorts of patients would be of more value than comparing aquatic physiotherapy versus land based alternatives with a heterogeneous sample. Study cohorts should mirror clinical practice and as such it would be interesting to research the effect of aquatic physio on patients with axSpA who struggle to tolerate land based exercise, have high disease activity or are being considered for escalation to Biologic therapy.

As part of a multi-modal approach to holistic care in axSpA it is important to consider qualitative research and other forms of evidence such as service evaluations, case studies and testimonials.  This can capture the positive impact on quality of life commonly seen and reported in clinical practice. We need to be better at collecting and sharing different forms of evidence as formal research takes time and money.  Led by NASS, the Aquatic Physiotherapy and Hydrotherapy Alliance will play a pivotal role in shaping the future of aquatic physiotherapy in the management of axSpA and other neuromusculoskeletal conditions.  As we move forward, aquatic physiotherapy services need supporting voices from within and out with the profession to advocate for this valuable specialty and indeed for our patients.  It is vital that we listen to our patients who are the experts in managing their condition as part of a person-centered approach to care.  People living with axSpA have long been telling us the benefits of hydrotherapy to their health and well-being. We need to aim for a future where there is equity of service provision and where clinicians through informed and shared decision making are able to prescribe the right rehabilitation at the right time to those most in need.

 Conclusion

Current published research evidence supports the prescription of aquatic physiotherapy in axSpA as an adjunctive therapy with potential added benefits to well-being, pulmonary function, use of healthcare resources and of medications.  There is also evidence to support aquatic physiotherapy as a second line intervention for those struggling to tolerate land-based exercise.  In this sense, aquatic physiotherapy could be considered a non-pharmacological second line intervention in the way that Biologic therapy is used as a second line intervention in the medical management of axSpA. Further quality research and evidence gathering is required to establish which people living with axSpA are likely to benefit most from aquatic physiotherapy.  In the meantime, clinicians can exercise clinical reasoning to provide person-centered care and prescribe aquatic physiotherapy for axSpA based on clinical need and individual preferences.

Alasdair