Development and evaluation of an exercise intervention programme to improve cardiovascular fitness and vascular responses in patients with rheumatoid arthritis

Cardiorespiratory fitness (CRF) has been selected as the primary end-point because of its importance as a surrogate predictor of cardiovascular events and because it is the only relevant parameter that has been previously assessed pre- and post-exercise interventions in RA patients. In studies with RA patients, or healthy participants exhibiting similar baseline CRF values to RA patients, CRF increased by approximately 20% (standard deviation [SD] = 6.0) following exercise interventions similar to the one we are proposing. We, therefore, included in our power calculation (nQuery Advisor v 6.0, Statistical Solutions, MA, USA) 20% as the expected change (i.e., from 25 ml/kg/min to 30 ml/kg/min) with SD = 6.0. The desirable number of participants for our study to produce significant results (p = 0.05) with a power of greater than 0.80, is 19 in each group. To allow for participant attrition, estimated at 25% for the six-month exercise intervention, we will recruit 25 RA patients in each of the groups. Data from participants with less than 75% compliance will be excluded from the analyses.

Assessment of CRF:
Exercise tolerance testing (ETT) will be adopted. Depending on each patient's functional limitations, a treadmill, a cycle ergometer or an arm ergometer will be utilised. CRF will be determined using a calibrated breath-by-breath system (Metalyzer 3B, CORTEX Biophysik GmbH, Leipzig, Germany) allowing continuous measurement of oxygen uptake (VO2), and lung ventilation. During ETT, blood pressure, heart rate and cardiac function using a 12 lead electrocardiogram (ECG), will also be monitored. Relevant data will be automatically stored every 30 seconds. Heart rate corresponding to 70% VO2max will be used to determine optimum exercise intensity.

Treadmills and cycles are the most commonly used devices for clinical exercise testing. The treadmill provides a more common form of exercise (i.e., walking) and patients are more likely to attain a higher oxygen consumption compared to cycling. However, cycling is a non weight-bearing activity, and, as such, might be more comfortable for patients with RA. Arm ergometer is an alternative method for exercise testing for patients that can not perform leg exercise, however, because lesser muscle groups are used, oxygen consumption is 20 - 30% lower compared to treadmill exercise. For non physically-active individuals, protocols with smaller increments between stages, such as ramp protocols, are more suitable. For treadmill testing, our protocol will start at a speed of 2.0 mph for 1 minute. Speed will increase thereafter by 0.5 mph every 1 minute until 4.0 mph. Thereafter, inclination of the treadmill will increase every 30 seconds by 1%. Testing is terminated when the participant reaches voluntary exhaustion. Cycle protocol will start with the patient cycling at 60 - 80 revolutions per minute with initial resistance of 25 Watts (W), as in the modified Astrand-Rhyming protocol. The resistance will be increased by 15 W every minute, until patient reaches voluntary exhaustion. Similarly, in arm ergometry, a constant cranking rate of 50 - 60 revolutions per minute will be kept. Initial resistance of 10 W will be increased by 5 W every minute.

Timepoints of assessments: CRF will be assessed at three different timepoints:
1. Baseline; before the participants are allocated to a group (intervention versus control)
2. Three months after the intervention (or control condition) has began
3. Six months after the intervention (or control condition) has began

Cardiovascular outcomes:
1. Individual risk factors for the development of cardiovascular disease (CVD) and 10-year CVD event probability: individual CVD risk factors (i.e. hypertension, hyperlipidaemia, hyperinsulinaemia) will be assessed. On the basis of these, the 10-year CVD event probability will be calculated using the latest version of the Joint British Societies' risk calculator.
2. In vivo endothelial function: endothelial function in the macrovasculature will be assessed using flow mediated dilation when the patient is in a fasted state. The brachial artery will be monitored by Doppler Ultrasound (ACUSON Antares ultrasound system with a VF 10-5 Transducer and SieClear, BW SieScape Imaging software, Siemens PLC, Munich, Germany) before, during, and after flow mediated dilation as well as administration of a single dose of nitro-glycerine (Glyceryl Trinitrate oral spray).
3. Endothelial function in the microvasculature will be assessed using Laser Doppler dual wavelength imaging (Moor LDI-2 SIM, Moor Instruments Ltd, Devon, UK). Acetylcholine, an endothelium-dependent vasodilator, and sodium nitroprusside, and endothelium-independent vasodilator, will be separately administered by iontophoresis. Blood flow will be assessed continuously 1 minute before iontophoresis and 2 minutes after iontophoresis using laser Doppler imaging.

Rheumatoid arthritis outcomes:
1. Disease activity: using the disease activity score 28 (DAS28). This is a composite assessment consisting of the patient's self-assessment of overall health during the last week on a visual analogue scale, a 28-joint count and the current erythrocyte segmentation rate (ESR). Serological assessments of disease activity are described below.
2. Physical function: using the Anglicised version of the 40-item Stanford Health Assessment Questionnaire (HAQ). Participants will rate their ability (over the past week) to carry out 20 activities within eight aspects of daily living (dressing/grooming, rising, eating, walking, hygiene, reach grip and errands/tasks) on a four-point scale from 'without any difficulty' to 'unable to do'. For each aspect patients also respond whether they receive assistance from people or use specific devices. The HAQ is internally consistent (a = 0.89) and has excellent pre- to post-physician visit temporal stability (r = 0.99). Physiotherapists' ratings have excellent agreement with RA patients' ratings.
3. Psychological well-being: anxiety and depression will be assessed using the Hospital Anxiety and Depression Scale (HADS). The HADS consists of 14 items (7 each for anxiety and depression) rated on various four-point scoring systems. Comparisons with psychiatric ratings have shown both subscales to be discriminantly valid. The subscales are also internally consistent (a = 0.85 and 0.78, respectively) and convergently valid among RA patients. Quality of Life will be assessed using the EuroQol (EQ-05). The EQ-05 questions self-assessed problems across five items on mobility, self-care, usual activities, pain, discomfort and depression/anxiety. Each item has three levels of severity: 'no problems', 'some problems' and 'severe problems'.
4. Serological assessments of risk factors, inflammatory mediators and endothelial function: full blood count, serum biochemistry, ESR, high sensitivity C-reactive protein [hsCRP], blood glucose, lipids, von Willebrand Factor (vWF) and thrombotic variables will be assessed using routine laboratory procedures in our laboratory. Internal quality controls on all analysers are carried out daily, and external quality controls fortnightly, utilising the Welsh External Quality Assurance Screen (WEQAS). Insulin will be measured using a solid phase two-site chemiluminescence immunometric assay using an Immunolite 2000 Analyser (Diagnostic Products Corporation, Los Angeles, CA, USA). Insulin sensitivity will be assessed by calculating the Homeostasis Model Assessment - Insulin Resistance (HOMA-IR) and Quantitative Insulin Sensitivity Check Index (QUICKI). Relevant cytokines and adhesion molecules (vascular panel, including: interleukin 1a [IL1a], interleukin 1b [IL1b], IL2, IL4, IL6, IL8, IL10, tumour necrotising factor alpha [TNFa], interferon-gamma, vascular endothelial growth factor, endothelial growth factor, macrophage chemo-attractant protein-1, inter-cellular adhesion molecule-1, vascular cell adhesion molecule-1, E-Selectin, P-Selectin, L-Selectin) will be measured using a fully automated RANDOX biochip array system (Randox Laboratories Ltd, Co. Antrim, UK) in our research laboratory. This performs simultaneous quantitative detection of multiple analyses from a single sample.

Timepoints of assessments:
1. Baseline; before the participants are allocated to a group (intervention versus control)
2. Three months after the intervention (or control condition) has began
3. Six months after the intervention (or control condition) has began