Physical function, physical activity and quality of life in systemic sclerosis

Abstract

Background and aims: Systemic sclerosis (SSc) is a multisystem rheumatic disease characterized by fibrosis, vasculopathy and immune system activation. There is a dearth of knowledge how different subphenotypes such as patients with no–mild and moderate–end-stage lung disease differs in physical function and activity, muscle function and active range of motion. Likewise, no study has yet investigated what experiences patients with SSc have of physical activity and exercise. Although it is known that many patients with SSc have physical disabilities, reduced health-related quality of life (HRQoL) and have anxiety and depression symptoms, little is known about differences between patients with no-mild and moderate-end-stage lung disease respectively. The overarching aim of this thesis was to increase the knowledge of physical function, physical activity and HRQoL in patients with SSc and different degrees of lung disease. The specific aims were to investigate the differences in physical capacity, physical activity, muscle function and range of motion in comparison with population-based controls or reference values. Further, a specific aim was to explore patients’ own experiences of physical activity and exercise.

Participants and methods: Three Cross-sectional studies were performed. In paper 1, 106 patients with SSc and 106 age- and gender-matched population-based controls were involved. In paper II, 205 patients with SSc were compared with reference values and in a paper III, 279 patients were involved. Further, a qualitative study with interviews of 16 individuals with SSc were performed and underwent a content analysis.

Results: Paper I. Patients with SSc reported overall lower physical capacity for walking, jogging, and running, and more limiting factors for physical capacity than controls. Patients with no–mild lung disease reported pain more often than their controls, whereas moderate–severe lung disease patients reported cardiopulmonary disease and reduced muscle strength as limiting factors for physical capacity more often than their controls. More patients than controls had ‘never exercised’ for at least 30 min per occasion within the past year; however, there were no differences overall between patients and controls in frequency of exercise, physical activity, nor time spent sitting. Paper II. Shoulder- and hip flexion muscle endurance were lower in relation to reference values, median [53% and 40% of predicted], respectively. Patients with moderate–end-stage lung disease had lower endurance in shoulder- and hip flexion [39% and 35%] than patients with no-mild lung disease [57% and 48%]. All patients, regardless subtype/grouping, needed longer time to complete the Timed-Stands Test (TST) [21 s] compared to reference values [17 s], and patients with moderate–end-stage lung disease needed longer time to complete TST than patients with no-mild lung involvement, [25 s vs 19 s]. Active range of motion in shoulder-arm were lower compared with reference values, and patients with dcSSc had lower shoulder-arm movement than patients with lcSSc. Paper III. The following three themes (and categories) emerged from the analysis: Essential for life and health (Diminishes symptoms and is as effective as pharmaceuticals, Reduces fear of deterioration, and, Feeling healthy and satisfied with oneself); Disease-related and other hindrances (Breathlessness, pain and other disease consequences limit, Risk of worsening, and, Non-disease barriers); and, Own understanding about physical activity/exercise and support from healthcare (Experience-based knowledge about own capability and physical activity/exercise, and, Education and support from healthcare and others). Paper IV. Patients with moderate–end-stage lung disease scored lower on Medical Outcomes Trust Short Form 36 (SF-36) physical component score than no–mild. Patients with moderate–end-stage lung disease had lower physical capacity, were less physical active on low-moderate intensity and exercised less the past year compared with no–mild. Patients with moderate–end-stage lung disease scored higher on Health Assessment Questionnaire (HAQ) and higher scores on Hospital Anxiety Depression scale (HADs), than the no–mild group. In the whole SSc sample, the SF-36 physical component score correlated highly with HAQ and moderately with symptoms on HAQ-VAS-general, dyspnoea, pain; and physical capacity, while SF-36 mental component score correlated moderately with anxiety and depression (HAD).

Conclusions: Although SSc patients reported lower physical capacity and more limiting factors for physical capacity than controls, there were no differences in reported physical activity and time spent sitting. However, SSc patients have markedly reduced muscle endurance in both the upper and lower extremities, reduced muscle strength in the lower extremities and impaired active range of motion in the shoulders and arms. Patients with moderate-end stage lung involvement had more impaired muscle endurance and strength than those with no-mild lung involvement but surprisingly no differences were found between lcSSc and dcSSc patients. Among individuals with SSc with both no-mild and moderate-end-stage lung disease, physical activity and exercise was expressed as essential for life and health and that it reduces fear of deterioration. Nevertheless, it was also expressed as a risk for worsening. As patients with SSc with moderate-severe lung disease have lower physical capacity, are less physically active and exercise less, are more physically disabled, have a lower physical HRQoL and have more depressive symptoms than patients with no-mild lung disease, individualized physical activity and exercise support from physiotherapist might be beneficial. The studies included in this thesis contributes to new knowledge, about how to develop and evaluate future physical exercise programs including resistance training for patients with SSc, especially for those with more severe lung disease.