The role of pain in chronic pain patients' perception of health-related quality of life: a cross-sectional SQRP study of 40,000 patients.

Abstract

Background and aims Health-related quality of life (Hr-QoL) reflects the burden of a condition on an overarching level. Pain intensity, disability and other factors influence how patients with chronic pain perceive their condition, e.g. Hr-QoL. However, the relative importance of these factors is unclear and there is an ongoing debate as to what importance pain measures have in this group. We investigated the importance of current pain level and mood on aspects of Hr-QoL in patients with chronic pain and investigated whether such relationships are influenced by demographics. Methods Data was obtained from the Swedish Quality Registry for Pain Rehabilitation (SQRP), between 2008 and 2016 on patients ≥18 years old who suffered from chronic pain and were referred to participating specialist clinics. Dependent variables were general Hr-QoL [using two scales from European Quality of Life instrument: EQ5D Index and the European Quality of Life instrument health scale (EQ thermometer)] and specific Hr-QoL [from the Short Form Health Survey (SF36) the physical component summary (SF36-PCS) and the mental (psychological) component summary (SF36-MCS)]. Independent variables were sociodemographic variables, pain variables, psychological distress and pain attitudes. Principal component analysis (PCA) was used for multivariate correlation analyses of all investigated variables and Orthogonal Partial Least Square Regression (OPLS) for multivariate regressions on health aspects. Results There was 40,518 patients (72% women). Pain intensity and interference showed the strongest multivariate correlations with EQ5D Index, EQ thermometer and SF36-PCS. Psychological distress variables displayed the strongest multivariate correlations with SF36-MCS. Demographic properties did not significantly influence variations in the investigated Hr-QoL variables. Conclusions Pain, mood and pain attitudes were significantly correlated with Hr-QoL variables, but these variables cannot explain most of variations in Hr-QoL variables. The results pinpoint that broad assessments (including pain intensity aspects) are needed to capture the clinical presentation of patients with complex chronic pain conditions.