When systemic lupus erythematosus (SLE) involves pain : occurrence and impact on daily life

Abstract

Living with a rheumatic disease, such as systemic lupus erythematosus (SLE), can pose many challenges. SLE is commonly considered to be a chronic disease, often occurring in unpredictable flares with alternating low and high disease activity. The disease predominantly affects women, but incidence and prevalence differ across different populations. SLE may potentially affect most organ systems with corresponding subjective symptoms, as well as objective signs. In general, pain is a commonly reported symptom in patients with SLE. Other common symptoms are fatigue, anxiety and depression. Patients with SLE are also reported to have a poorer health-related quality of life (HRQoL) compared to the general population. All these factors constitute a potential risk for impairment of health as well as a negative impact on daily life. Even though there is no cure for SLE, modified treatment regimens and new, potentially active drugs have been developed in recent decades. However, previous studies have shown that patients consider SLE-related pain not to be sufficiently addressed by healthcare providers. Even considering modified treatment regimens, the heterogenous nature of SLE, as well as new findings on pain mechanisms, the question of whether SLE-related pain is still common and constitutes a health barrier remains unanswered. As far as we know, no studies have been conducted in recent years in which HRQoL, fatigue, anxiety, and depression have been investigated from a pain and degree of pain perspective. More detailed knowledge on extent, intensity and characteristics is therefore required. In addition, the chronic course of SLE underlines the importance of investigating how SLE-related pain varies over time, and the patient’s experience of how healthcare providers address SLE-related pain.

Aim: The aims of this thesis were to explore to what extent patients with SLE report diseaserelated pain and how pain relates to HRQoL, fatigue, anxiety and depression, as well as to disease duration, disease activity and damage. The aim also included investigation of how the pain varies over time and impacts on daily life.

Method: Data were collected from two cross-sectional cohort studies at inclusion (year 0) and seven-year follow up (year 7). At year 0, 84 patients with SLE and 91 age- and sexmatched controls from the general population completed self-assessment measures and questionnaires on pain using the Visual Analogue Scale (VAS) and the short-form McGill Pain Questionnaire (SF-MPQ); fatigue using the Multidimensional Assessment of Fatigue (MAF); HRQoL using the Medical Outcomes Survey-Short Form 36 (SF-36); and anxiety and depression using the Hospital Anxiety and Depression Scale (HADS). These assessments and questionnaires were completed again at year 7, when 64 of 84 patients with SLE and 68 of 91 gender- and age-matched controls from the inclusion cohort participated. In addition, data on age, disease duration, disease activity and damage, as well as treatment with glucocorticoids were collected at both years 0 and 7. At year 7, data collection was supplemented with assessment of pain-related problems (VAS), data on pain duration, a pain drawing, and data on analgesics. At year 0, the patients were dichotomized into two groups designated the low-pain group and the high-pain group based on their SLE-related pain intensity score using VAS. A cut-off value, 40 millimetres, was chosen based on the distribution of scores using VAS. The division into the low-pain group and the high-pain group at year 0 was used for intra-group comparisons of collected data at both year 0 and year 7. A qualitative approach was applied to investigate the impact of SLE-related pain on health and daily life, as well as the patient’s expectations of healthcare providers. Twenty patients from two cohorts in the same urban region, south and north, participated in an interview study. The recorded interviews were based on an interview guide and transcribed verbatim. Thereafter, the text was analysed using qualitative content analysis.

Results: At year 0, the patients in the high-pain group constituted 24% of the SLE cohort and were characterized by significantly shorter disease duration and higher disease activity compared to the patients in the low-pain group. The patients in the high-pain group used significantly more descriptive words compared to the patients in the low-pain group when scoring their pain intensity using SF-MPQ. They also reported significantly lower HRQoL and scored higher levels of fatigue, anxiety and depression compared to the patients in the low-pain group and the controls. However, the low-pain group did not differ significantly from the controls regarding reported pain, fatigue, anxiety and depression. Treatment with glucocorticoids did not differ between the pain subgroups, and patients treated or not treated with glucocorticoids did not differ when scoring pain intensity. At follow-up in year 7, the high-pain group scored significantly lower levels of SLE-related pain using VAS. However, only half of the patients in the high-pain group scored a lower pain intensity while the other half had an unchanged pain score level from year 0. These patients with remaining high pain level scored statistically similar levels for HRQoL (except for a poorer score for the dimension vitality), as well as for fatigue, anxiety and depression as year 0, and significantly poorer scores in all self-reported assessments except for anxiety (HADS) and mental health (SF-36), compared to the patients with decreased pain, the low-pain group and the controls at year 7. Conversely, the patients with decreased pain scored significant improvements in all self-reported assessments. The patients in the low-pain group scored statistically similar levels for pain, most dimensions of HRQoL (SF-36), as well as for fatigue, anxiety and depression at year 7 as at year 0. Further, the patients in the low-pain group scored mainly statistically similar levels as the controls and the patients with decreased pain at year 7. In the interview study, the informants delineated their disease-related pain as long-standing, unpredictable and migratory. They also depicted a high symptom burden from their diseaserelated pain on health and daily life. The informants used several strategies to deal with pain, mainly through adaption and by finding new ways to perform different tasks and to maintain their roles in relation to others. They expected their pain to be acknowledged and to be met well by the healthcare providers. Furthermore, interventions against pain which were not dependent on economic prerequisites, and individual tailored advice and information were also requested.

Conclusion: Taken together, the results from these studies revealed that severe SLE-related pain (≥40 mm on VAS) is present in a minority of the patients with SLE. Furthermore, the pain intensity tended to decrease over time. Despite that, the patients with remaining severe pain reported a high symptom burden with impaired HRQoL, more fatigue, anxiety and depression, even though mental health appeared to be less affected. In spite of the fact that patients with severe pain use several strategies to deal with pain, individual adapted interventions designed to alleviate pain and support for the patients are strongly needed from healthcare providers. Moreover, acknowledgement of SLE-related pain is crucial.