Characteristics and outcomes of chronic pain patients referred to hospital pain clinics: a prospective observational study

BACKGROUND: Understanding the patient referral patterns and medical profiles of patients attending hospital pain clinics, and the therapies offered to them, can provide a useful starting point for evaluating their effectiveness and identifying areas for improvement. METHODS: A prospective observational study was carried out. Sociodemographic and clinical data were gathered at twelve centres. The diagnoses and pain treatments provided by the referring doctors were compared with the ones provided by pain clinicians. Pain severity and patients' quality of life were measured prospectively. Descriptive statistics were compared. RESULTS: Two-hundred sixty-nine patients referred to 12 outpatient hospital pain clinics in Catalonia were followed for 3 months. Most were referred by orthopaedists (50.0%) or primary care physicians (20.2%). The mean age and time since pain onset were 59.4 and 4.1 years, respectively. Pain clinicians changed the diagnostic labels of 48.5% of the patients. Nearly all patients (89.2%) were receiving pain medications prior to referral. Treatment was modified in 94.8%. Pain clinicians used more interventional and/or alternative therapies (65.1% of patients), opioids (46.8%) and co-adjuvants (38.2%). Three months after referral, the 24-h worst and current pain severity had decreased by 30.9% and 27.8% on average, respectively. The mean (effect size) improvements in a quality of life (the EuroQol 5 Dimensions index) and pain (visual analogue scale) scores were, respectively, 0.16 (0.73) and 6.7 (0.31). CONCLUSIONS: Pain clinicians refined the diagnoses and treatments of patients referred to hospital pain clinics and improved outcomes. Relatively few patients are referred from primary care considering the prevalence of chronic pain in this setting.