Long term oxygen therapy (LTOT) is proven to increase the survival of patients with respiratory failure, most commonly from diseases such as Chronic Obstructive Pulmonary Disease (COPD). At least 15 hours' usage per day is needed to improve mortality. Most patients on LTOT utilise bulky oxygen concentrators (OC) which run on continuous Alternating Current (AC) power. This intervention, however, limits patient mobility and social engagement as patients are tethered to their device and confined to their homes.

Reduced physical activity levels have been shown in COPD patients to be associated with reduced quality of life (QoL), increased admission rates to hospital and survival even after adjustment for severity of COPD. Significant benefits stand to be made by improving physical activity levels in LTOT patients. Pulmonary Rehabilitation (PR), which is traditionally conducted in a healthcare setting, is an established intervention that addresses this by improving exercise tolerance but uptake and completion rates have been low due to reasons such as cost and difficulty with transport. LTOT usage is also cited as an independent barrier to PR.

The investigators propose the establishment of a 10-week home-based physiotherapy programme as a novel community-centric and resource-lean intervention that seeks to improve the physical activity level of LTOT patients. Patients will be prescribed an ambulatory oxygen device and receive education on its usage in conjunction with a home exercise regimen which includes a home visit and subsequent telephone support by a physiotherapist in partnership with a community-based healthcare provider.

A prospective pilot study of 30 patients is proposed. The outcome measures include mobility function, activity levels, generic and disease-specific QoL.

If successful, our programme may revolutionize the approach to LTOT patients in Singapore and improve their ability to function independently in the community greatly; in addition, the reduction in hospital-based healthcare utilisation is greatly advantageous.

This will be an investigator-initiated, prospective pilot study which aims to recruit 30 patients in total and conducted over 24 months.

Study Aims and Hypotheses: Utilisation of healthcare resources and burden of care on society for LTOT patients is disproportionately high. The study investigators aim to describe this group of patients and introduce an intervention that aims to promote quality living with a home-based physiotherapy programme.

1. To test the hypothesis that the intervention of a home-based physiotherapy programme together with a lightweight POC will improve physical activity level, reduce daily time spent in sedentary activity, improve Quality of Life (QoL) and reduce symptoms of anxiety and depression of patients on LTOT
2. To describe the functional status of patients on LTOT and their caregivers - physical activity levels, body mass index, psychological, socio-economic background, activities of daily living (ADL) status
3. To describe the barriers to uptake of ambulatory oxygen in patients who fulfil criteria for LTOT
4. As there is a lack of local data on the effectiveness and safety of a home-based physiotherapy program, the study being conducted is a pilot study intended to establish the feasibility of a home-based physiotherapy programme

STUDY BACKGROUND

1. Long-term oxygen therapy (LTOT) is an established medical intervention that has been shown to prolong the survival of a select group of patients with respiratory failure (1, 2). Although local data on the incidence and prevalence of LTOT use in Singapore is lacking, it has been reported in the Danish Oxygen Register that the annual incidence and prevalence of LTOT use in 2010 was 32.2 and 48.1 per 100,000 inhabitants respectively (3). Older studies have reported a LTOT prevalence of 28 per 100,000 in 1992 in the French Oxygen Register (4), LTOT incidence and prevalence of 7.1 and 24 per 100,000 respectively in 2000 in the Swedish Oxygen Register (5) and prevalence of LTOT of 241 per 100,000 in the USA in 1994 (6). Chronic Obstructive Pulmonary Disease (COPD) is by far the main respiratory diagnosis in LTOT patients followed by other diseases such as interstitial lung disease and bronchiectasis (7). In addition, the medical literature has documented rising LTOT usage over the years due to reasons such as increasing survival of COPD patients and increased physician and patient awareness of the benefits of LTOT (8). The costs of LTOT have been recognised to be high, with an estimated 800,000 patients in USA utilising LTOT at cost of approximately $1.4 billion American dollars annually according to a 1995 publication by O'Donohue et al (9). Total Medicare payments for LTOT in 1998 were reported to be USD 1.3 billion (10). A more recent analysis of 329,482 Medicare beneficiaries with COPD who received oxygen from 2001 to 2010 found that 73,659 (22.4%) received oxygen therapy (8).

2. The majority of patients utilise oxygen concentrators (OC) (3,11) which typically run on continuous AC power and weigh between 13-22kg. This intervention, although life-prolonging, nonetheless limits patient mobility as patients are required to utilise oxygen therapy for at least 15 hours a day to benefit. As a result, many patients become confined in their homes.

3. Indeed, patients with chronic respiratory disease requiring LTOT have been reported to be severely limited in their physical activity. Studies of patients on LTOT have shown that 46% of patients walk less than 600m per day (12) and up to 45% are house-bound (13). While this may be due to low exercise tolerance, oxygen therapy may be a contributory factor in itself as patients receiving oxygen from a stationary source often become tethered their device over time. Although there are theoretical benefits to improving exercise tolerance with oxygen therapy (14), it has been reported that patients with severe COPD on LTOT have significantly reduced levels of domestic activity compared with patients with COPD of similar severity but who were not on LTOT (15). Patients with severe COPD and broadly similar health status on LTOT have also been reported to be less independent on activities of daily living than those not requiring LTOT (16).

4. Apart from reduced quality of life, reductions in daily activity levels have been shown to be related to clinically relevant outcomes in COPD patients, such as reduced health status (17), hospital admissions (18, 19) and survival (19) even after adjustment for severity of COPD. Over the years, interest has shifted from improving exercise capacity to increasing daily physical activity (20) which is defined as any bodily movement produced by the contraction of skeletal muscles that increased energy expenditure (21). In fact, it was found in a prospective cohort study of 170 outpatients with stable COPD that objectively measured physical activity was the strongest predictor for all-cause mortality in patients with COPD and that there was a linear association between physical activity and mortality (22). Significant gains in quality of life and reduced utilisation of healthcare stand to be made if the physical activity and mobility profile of patients on LTOT can be increased.

5. An established intervention to improve the mobility and physical activity levels of LTOT patients is Pulmonary Rehabilitation (PR). PR is a structured, multidimensional and multidisciplinary programme over time (at least 6 weeks) that comprises physical training and breathing exercises supervised by a respiratory physiotherapist in conjunction with education guided by objective tests of the respiratory system and exercise capacity such as pulmonary function tests, 6-minute walk test and cardiopulmonary exercise testing. PR been shown to be cost-effective and beneficial in improving shortness of breath, health status and exercise tolerance in patients of all grades of COPD severity, including patients with chronic respiratory failure on LTOT (23).

6. Although the benefits of PR are established, uptake and completion of PR is frequently limited. The percentage of referred participants who did not attend PR at all ranged from 8.3 to 49.6% in a systematic review (24). Many barriers have been cited, such as low referral rates from healthcare providers (25) and low patient and healthcare provider awareness of its availability and benefits. Usage of LTOT has also been found to an independent predictor for non-attendance to PR (26). This is not surprising as patients on LTOT face even greater difficulty than the average patient in participating in PR due to challenges in being able to independently navigate the transportation system to attend outpatient PR whilst on oxygen therapy. Another major barrier worth mentioning is the lack of access from a combination of factors of geography, culture, finances, transportation and other logistics (27, 28). This may be due to the fact that PR is a healthcare-provider centric intervention that is traditionally conducted in a healthcare institution in an outpatient or inpatient setting.

7. Locally in Singapore, patients face a financial disincentive towards participating in PR in the outpatient setting as Medisave, the national medical savings scheme, imposes limits on withdrawals for outpatient healthcare expenditure. Outpatient PR also imposes hidden costs to the patient in the form of transportation and missed days at work for family caregivers who accompany the patient for outpatient PR. Patients are often accompanied by family caregivers or sponsors to healthcare visits in Singapore and the lack of a caregiver to accompany patients for outpatient PR is an important cultural barrier to PR. Inpatient PR in Singapore, on the other hand, is also limited in its capacity to serve many patients due to the national strain on hospital beds. PR clearly has its limitations as a modality in improving the poor physical activity levels of patients on LTOT and a novel solution is needed that addresses the many barriers with PR uptake.

8. The investigators are therefore proposing the establishment of a home-based physiotherapy programme as a novel community and patient-centric and resource-lean intervention that seeks to improve the physical activity of LTOT patients. Patients will be prescribed an ambulatory oxygen device and receive education on its usage in conjunction with a home exercise regimen which would include a home visit by a physiotherapist. It is hypothesised that home-based physiotherapy would be more patient-centric compared to healthcare centre-based physiotherapy as realistic rehabilitation goal settings and exercise regimens can be personalised to each patient's unique home and community environment, lifestyle and care needs. The proposed intervention would be similar to an 8-week home-based PR study recently conducted in the UK which comprised 1 home visit and 7 once-weekly telephone calls from a physiotherapist in the home-based intervention arm which found equivalent short-term outcomes (such as exercise tolerance and dyspnoea-related quality of life) that were equivalent to outpatient centre-based PR (29).

9. Ambulatory Oxygen (AO) is an important enabler in improving the mobility of patients on LTOT in the community and therefore their participation in PR. However there remain many barriers to the uptake of AO such as (i) lack of instruction on the usage of AO, and particularly with regards to AO delivered via oxygen cylinders, (ii) fear of running out of their AO supply while they were using it, (iii) embarrassment and (iv) difficulties with carrying the AO supply (30).

10. These barriers have led to low usage rates of AO via oxygen cylinder with only 39% of patients using AO for more than 2 hours a week in a Danish study published in 1999 (31). In the same study, it was reported that when patients had outdoor activity, the usage of stationary oxygen fell by a couple of hours, resulting in lower overall oxygen usage. This suggested that patients were spending a considerable time outside their home without using their AO (31). In Italy where LTOT is almost exclusively provided by liquid oxygen, it was reported that although most patients (84%) possessed an AO device, only 40% declared that they used it daily with "being ashamed of being seen by passersby with a stroller" being the principal barrier (7). Similar data was presented in a French study which reported that most patients (630/930) used their oxygen only while resting (32).

11. Compared to oxygen cylinders, AO delivered by lightweight Portable Oxygen Concentrator (POC) has the advantages of being (i) user-friendly, (ii) aesthetically more pleasing and is (iii) easily rechargeable with standard household electrical supply (33).

    Such advantages will overcome some of the aforementioned barriers to AO usage.

12. A prospective pilot study of 30 patients is proposed. Assessment of activity levels, QoL and breathlessness will be measured before and after 10 weeks. The 2 components of the proposed intervention, namely the home-based physiotherapy programme and the prescription of a lightweight POC are synergistic in its effects. Supplemental oxygen has been shown to improve exercise duration (34) and therefore rehabilitation while it has been shown that effective use of oxygen was improved by follow-up education, whether given by nurse or physiotherapist, after initiation of oxygen therapy (32). It has been shown that the prescription of AO alone does not automatically assure good adherence to the prescribed treatment or use of AO outdoors (30). The guidance from the home-based physiotherapy programme will comprise of a home visit by a physiotherapist with the aim of reinforcing compliance and usage of AO outside the house, thereby improving the patients' mobility over simply prescribing an AO device. It is hypothesised therefore that patients will be encouraged to use their AO device when they are guided by a home-based physiotherapy programme where rehabilitation goals and exercises are tailored to each patient's unique "life-space" in the home and community.

13. In summary, the proposed intervention of a home-based activity education programme in partnership with a community healthcare provider and in conjunction with a lightweight POC may revolutionize the approach to patients with chronic respiratory failure in Singapore and improve their ability to function independently in the community greatly; in addition, the ability to stay active and community ambulant as well as the reduction the demand on national healthcare resources (e.g. inpatient rehabilitation beds for PR) is greatly advantageous.

Note - References have been cited in subsequent sections

Inclusion Criteria (participants are required to fulfill all of the following criteria):

1. Patients aged 21-90 years old who are able to provide informed consent and have their consent signed and dated. Subjects must be able to complete questionnaires.
2. Patients who meet criteria for LTOT i.e. PaO2 ≤55mmHg on room air or PaO2 ≤59mmHg (with pulmonary hypertension, RV hypertrophy, Cor pulmonale, haematocrit ≥55%).
3. Patients should be on LTOT on ≥3 months (to avoid the inclusion of patients who were prescribed oxygen following acute illness).
4. Patients should have clinical stability of their underlying chronic cardiac (e.g. pulmonary hypertension) or respiratory diseases (e.g. COPD, ILD), as demonstrated by no recent acute exacerbation of respiratory/cardiac illness, acute healthcare utilisation (presentation to GP, polyclinic or hospital) or change in medication (or adjustments of non-invasive ventilation) for ≥6 weeks before enrolment.
5. Patients who are sufficiently mobile to perform a 6-minute walk test.

Exclusion Criteria:

1. Patients with any life-threatening condition with a low probability (in the opinion of the investigator) of survival for at least 3 months or who has been hospitalised more than 3 times in the preceding 1 year for respiratory failure.
2. Patients who are not able to ambulate with the lightweight POC (they must be able to perform a 6-minute walk test - this can be unaided or with walking aid) or who have significant limitation of ambulation due to non-respiratory causes such as musculoskeletal (e.g. osteoarthritis) or neuromuscular disease (e.g. Parkinson's disease or stroke), or who are assessed to have no rehabilitation potential.
3. Patients who are actively smoking.
4. Patients who are currently participating in a pulmonary rehabilitation programme.
5. Patients who are pregnant.
6. Patients who are unable or unwilling to complete questionnaires (e.g. patients on LTOT and home mechanical ventilation).