A lack of guidelines for inpatient management of low back pain means that treatment varies depending on whether a patient is admitted to a rheumatology or general medicine unit, Australian research shows.

Patients admitted to rheumatology units from an emergency department are more likely to receive spinal injections and neuropathic pain medications, more likely to have early physiotherapy and less likely to have imaging such as CT scans compared to patients managed in general medicine units, a study at Victorian hospitals has found.

Patients admitted to a general medicine unit are more likely to be treated with diazepam, more likely to have opioid-related complications and a longer stay in hospital.

The findings, published in the Internal Medicine Journal, come from a three-year retrospective review of 712 admissions for low back pain across three general medicine units and one rheumatology unit within the Monash Health network.

The most common diagnoses were musculoskeletal/nonspecific back pain (41%), disc-related illness (22%), vertebral fracture (14%) and sciatica (14%), with disc related and sciatica diagnoses more frequently admitted to the rheumatology unit.

Patients admitted for LBP tended to be elderly (average age 67 years) and had a high rate of comorbidities including mental health (26%), gastroesophageal reflux disease (25%), diabetes (23%), chronic airways disease/asthma (18%), osteoporosis (16%), ischaemic heart disease (16%), and malignancy (10%).

Almost all patients in all units received paracetamol and opioids, but patients in the rheumatology unit were significantly more likely to receive NSAIDs, neuropathic pain medications such as  such as pregabalin, and prednisolone injections.

Patients admitted to the rheumatology unit were also more likely to have physiotherapy and tended to have it within one to two days whereas patients in the general medicine unit sometimes waited up to eight days before receiving the first treatment.

Patients admitted to a general medicine unit were more likely to have an occupational therapy assessment, “which may reflect that they had more complex social care needs. This may account for some of the variation in management strategies,” said the study authors, led by Dr Leo Kyi of the Department of Rheumatology, Monash Health.

Predictors of complications and increased length of stay included Non-English Speaking Background (NESB), old age (≥80 years), disc-related disease, vertebral fracture and sciatica.

The high rates of imaging for patients admitted for LBP to a general medicine unit might reflect “lower confidence in clinical exclusion of emergency indications for imaging,” the study authors said. However, they noted that imaging rates were high across all units, with more than 75% of patients imaged.

The differences in management and outcomes for low back pain between rheumatology and general medicine units showed the potential to streamline and rationalise care pathways, they suggested.

“A divergence in length of stay was observed between diagnoses of canal stenosis, vertebral fracture, and sciatica, compared to musculoskeletal/non-specific back pain or discogenic back pain. Earlier discharge for patients with these diagnoses might therefore be possible,” they wrote.

“Patients with vertebral fracture, or sciatica were also more likely have complications during their admission. This suggests that patients with these diagnoses ought be more closely monitored in an effort to avoid complications.”