Current management practices for patients presenting with low back pain to a large emergency department in Canada

We conducted a retrospective cross-sectional analysis of six years of clinical data from the administrative Emergency Department Information System (EDIS) dataset of the Charles V. Keating (QEII HSC ED) Emergency and Trauma Centre, in Halifax, Nova Scotia, Canada, supplemented with data from linked patient charts. Data was collected between July 15, 2009 and July 15, 2015.

Halifax is the provincial capital of Nova Scotia and is a coastal city in eastern Canada. The QEII HSC ED, a tertiary care center, is the largest ED in Atlantic Canada. It typically serves 186 patients in a 24-hour period. Daily, there are approximately 30 ambulance arrivals and between 1-6 emergency helicopter arrivals. There is a total of 36 patient spaces (3 trauma rooms) in the ED and the department averages approximately 1.5 traumas a day. When arriving at the ED, patients are triaged based on presenting complaint and a limited physical exam with vitals is conducted. There are two treatment areas within the ED, the main ED and a minor treatment area where patients do not need to be monitored by nursing staff. Depending on the patient’s condition and triage level, they are seen by a physician in one of these areas. All patients presenting to the ED are seen, regardless of compliant. Low back pain accounts for approximately 2100 visits per year at the QEII HSC ED [7]. This study was reviewed and approved by the Nova Scotia Health Authority Research Ethics Board.

We assessed management of non-urgent LBP for adults aged 16 and older (the minimum age of intake in the QEII HSC ED) presenting to the ED. We included patients with non-urgent LBP, defined by two subgroups – non-specific LBP and LBP with neurological signs or symptoms – using ICD-9 diagnostic codes (Appendix). Non-specific LBP was defined as localized pain, muscle tension, or stiffness without an identifiable, known pathology [10]. LBP with neurological signs or symptoms is attributable to spinal joints, discs, vertebrae, muscle or soft tissues. For this subgroup, the presence of radiculopathy and lumbar spinal stenosis were screened for in the review. Radiculopathy was defined as impairment of a nerve root, with symptoms of radiating pain, numbness, tingling, or signs of muscle weakness corresponding to a specific nerve root. Lumbar spinal stenosis was defined based on signs of neurogenic claudication, such as worsening of pain with activity and in certain postures, relieved by rest. Signs and symptoms of lumbar spinal stenosis included discomfort, sensory loss, and weakness in the legs, reflecting involvement of spinal nerve roots within the lumbar spinal canal. An additional pathologic cause LBP subgroup was described as LBP attributed to a specific, often serious cause, not primarily related to the back, such as abdominal aortic aneurysm, pancreatitis, pyelonephritis, or cancer. Patients receiving a diagnostic code compatible with pathologic cause LBP were excluded. In addition, we excluded patients deceased on arrival.

Using a computerized random number generator, we selected a simple random sample of 325 patients who presented to the ED with non-urgent LBP over the study period for this focused supplemental review. This sample size was determined to reflect variation in the population and specifically identify an adequate number of LBP patients who had LBP with neurological signs or symptoms; estimated to be approximately 10% of the non-urgent LBP population.

Information was extracted from the EDIS database for important participant factors including, but not limited to, age, gender, length of stay, triage coding, and diagnosis coding. The QEII HSC ED uses the Canadian Triage Acuity Scale (CTAS) for triage coding and ICD-9 for diagnosis coding. In Canada, CTAS is a five-level scale for classifying the acuity of a patient’s condition (1 = resuscitation, 2 = emergent, 3 = urgent, 4 = semi-urgent, and 5 = non-urgent) based on the presenting complaint. In terms of assessing pain severity in association with CTAS level, it considers the location, severity, and acuity to better predict life-threatening conditions [11]. The CTAS tool has been found to be a valid instrument for predicting admission rates, hospital length of stay, and diagnostic utilization [12]. The ICD-9 coding system is used in many facilities across the country and remains a high standard in disease coding. It was revised in 2013 by the National Centre for Health Statistics (NCHS) and the Centre for Medicare and Medicaid Services (CMMS) found in the US. An electronic data extraction tool was developed in MS Access to aid in a highly-targeted patient chart review. This provided data on variables that were not available through EDIS related to the care provided in the ED and discharge instructions.

We recorded information about diagnostic tests utilized in the ED to investigate non-urgent LBP, treatment either administered or prescribed, and additional care provided. Diagnostic testing included plain radiograph, CT, MRI, urinalysis, and bloodwork. Treatment strategies included pharmacological and non-pharmacological therapies delivered in the ED and any prescriptions at discharge. Pharmacologic interventions were grouped into the following drug categories: anti-inflammatories, analgesics, opioids, and muscle relaxants. Care provided included referral to family physician, referral to medical specialist, referral to physiotherapy, and a documented discharge or follow-up plan. Other variables included in the analysis described patient characteristics, LBP features, and the utilization of health services. Patient characteristics included age, sex, responsibility for payment, and whether the patient had a primary care provider. Low back pain was described by CTAS score, discharge diagnosis (using EDIS and chart), type of ED visit, presenting level of pain, duration of LBP complaint, and the presence or absence of sciatica and neurological symptoms. Presence of sciatica was defined as pain, numbness, tingling in the distribution of the sciatic nerve, radiating down the posterior or lateral aspect of the leg, usually to the foot or ankle. Presenting level of pain was captured in triage by EDIS and in the chart review independently. Both used an 11-point numerical rating scale for pain (0-10). Severity of pain was categorized based on this scale into mild (0-3), moderate (4-7), and severe (8-10) pain, the same groupings used in the revised CTAS guideline [11]. Duration of LBP complaint was recorded in weeks since the onset of low back pain and categorized as acute LBP (less than 4 weeks), subacute LBP (4 weeks to less than 12 weeks), or chronic LBP (greater than 12 weeks) [5]. Health service use measured method of arrival, arrival date and time, departure date and time, and departure destination.

Data were analyzed using STATA IC 13.1 statistical software, including descriptive analyses and assessment of characteristics associated with outcomes. Categorical variables were described with frequencies (%). Continuous variables with a normal distribution were described with a mean value and standard deviation. If the data was not normally distributed, we used a median value with interquartile range in the analyses. Patterns of missing data were examined and described.