Chronic pain is persistent or recurring pain lasting more than 3 months past normal healing time. Primary care professionals usually refer patients experiencing chronic pain to pain specialists to better identify, treat, and manage the pain. Chronic noncancer-related pain affects more Americans than diabetes mellitus, cardiac disease, and cancer combined.1 Veterans are no exception. The prevalence of severe pain was significantly higher in veterans compared with that of nonveterans who had back pain (21.6 vs 16.7%, respectively), jaw pain (37.5 vs 22.9%, respectively), severe headaches or migraine (26.4 vs 15.9%, respectively), and neck pain (27.7 vs 21.4%, respectively).2 At an individual level, those who experience chronic pain can expect impaired functional capacity, reduced ability to work, sleep disturbance, reduced social interactions, and considerable psychological distress. At a societal level, the cost of treating chronic pain is exorbitant, exceeding $600 billion annually, yet treatment outcomes remain variable at best.3 Greater efforts are needed to improve and standardize patient outcomes.
Interventional pain procedures performed under fluoroscopic or ultrasound guidance by specialist physicians have shown mixed responses in previous studies. Past systematic reviews demonstrate reductions in pain scores after lumbar or caudal epidural steroid injections (ESIs) and radiofrequency ablation of nerves supplying lumbar and thoracic facet joints.4-7 However, one review found insufficient evidence to support injection therapy for chronic low back pain.8 Unfortunately, the majority of the included studies evaluated outcomes using the visual analogue scale (VAS) or other limited factors, such as physical examination findings. Current biopsychosocial conceptualizations of chronic pain are beginning to recognize the complex nature of the experience of pain and highlighting the significance of multimodal management.9 It is vital that our assessment of chronic pain, like our treatment options, be multidimensional and reflect these underpinning principles.
The Pain Outcomes Questionnaire-For Veterans (POQ-VA) was developed within the Veterans Health Administration (VHA) by Clark and colleagues in 2003. It represents a brief but psychometrically sound pain outcomes instrument that assesses all key domains and meets accreditation body standards. The POQ-VA is valid and reliable for evaluating effectiveness of treatment of chronic noncancer pain in veterans in routine clinical practice.10 This review is the first study to use the POQ-VA to assess the impact of interventional pain procedures on veterans with chronic noncancer pain.
The aim of this study was to perform a retrospective review of POQ-VA scores before and after injection-based interventional treatment for chronic pain to determine whether the procedure affected patient outcomes. We hypothesized that POQ-VA scores would improve across multiple domains in the veteran population postprocedure. This study was approved by the Institutional Review Board (IRB-2018-053) at the Providence Veterans Affairs Medical Center (VAMC) in Rhode Island.
Methods
Using the Computerized Patient Record System, all adult veteran patients who had attended at least 2 appointments between April 1, 2009, and April 1, 2019 at the Providence VAMC interventional pain clinic were identified. POQ-VA reports were extracted provided the following criteria were met: (1) the veteran received an injection-based interventional treatment for chronic pain, including trigger point injections, ESIs, nerve blocks, and radiofrequency ablations; (2) the veteran completed POQ-VA both pre- and posttreatment; and (3) posttreatment POQ-VA reports were completed within 6 months of treatment. All patients who did not fit these criteria were excluded from the study.
After deidentification, 112 pre- and posttreatment POQ-VA reports were identified. All subsequent statistical analyses were conducted using Stata SE version 15. Descriptive statistics including mean, range, SD, and percent change were computed for POQ-VA domain—pain, mobility, activities of daily living (ADL), vitality, negative affect, fear, and total raw score—as well as for each POQ-VA question. Given that POQ-VA domain scores were found to be approximately normally distributed without outliers, domain scores were treated as continuous variables, and a paired samples t test was conducted to compare means among POQ-VA domains. Individual question responses were analyzed using nonparametric testing methods to account for the lack of normal distribution in each question, treating the range of 0 to 10 as an ordinal variable. A Wilcoxon matched-pairs signed-rank test was conducted to compare means among individual question responses before and after treatment.
Results
Of 112 included patients, 102 (91%) were male and 10 (9%) were female. The mean age was 62 years (range, 35-90). Diagnosis and procedures varied due to patient symptoms varying from muscle pain, nerve pain, degenerative disc disease, and osteoarthritis.
POQ-VA scores across all domains, including total raw score, showed statistically significant improvement after treatment (Table 1). Directionally, the POQ-VA scores for all 20 questions reflect a positive treatment response and 17 had statistically significant changes (P < .05) (Table 2). The changes in self-perceived energy level, safety, and feelings of tension were not statistically significant. Esteem had the greatest magnitude decrease, falling from 5.2 preprocedure to 3.8 postprocedure (P < .001). Other similarly significant magnitudes of improvement were seen from pre- to postprocedure in questions pertaining to grooming (2.2 to 1.6, P = .003) and the ability to use the bathroom (3.4 to 2.6, P < .001).