- Ontario chiropractors steadily used fewer X-rays on patients between 1994 and 2001. A potential reason is that clinical practice guidelines have been recommending against the use of X-rays for low-back pain unless a serious underlying disease is suspected.
Why was this study done?
This study looked at the annual costs and use of low-back and full-spine X-rays among Ontario chiropractors between 1994 and 2001. During this period, at least a dozen evidence-based guidelines on the clinical management of low-back pain were published. All recommended against the use of X-rays unless a serious underlying problem was suspected. Given that chiropractors see one-third of patients in Ontario seeking help for low-back pain, this study aimed to find out if these guidelines were influencing their practice.
How was the study done?
The costs and use of X-rays by chiropractors were measured each year from 1994 to 2001 using information from the Ontario Health Insurance Plan (OHIP) and Workplace Safety and Insurance Board (WSIB). These are the two main payers for health-care services in Ontario. The information collected included the total number of claimants seeing a chiropractor, total number of visits, the number and type of X-ray services, the number of chiropractors billing OHIP or WSIB, and the fee paid for each service.
What did the researchers find?
There were declines in X-ray use and costs. The figures below are from the start of the measurement period (1994) and the end (2001). X-ray use was the proportion of claimants getting an X-ray.
- low-back X-rays — dropped overall from about 4.5 per cent to just over three per cent, with a 13 per cent decrease in OHIP payments (from about $645,000 to under $563,000)
- full-spine X-rays — dropped from about four to three per cent, with a five per cent decrease in costs (from $1.13 million to $1.07 million).
- low-back X-rays — went from 6.5 per cent to just over three per cent, with an overall 44 per cent decrease in payments during the study period (from almost $56,000 to $31,000)
- full-spine X-rays — went down from 1.5 to just under one per cent for an overall 34 per cent drop in payments (from nearly $18,000 to less than $12,000).
These decreases occurred despite an increase in the number of claimants and chiropractors during the same period.
What are some strengths and weaknesses of the study?
The large number of claimants and the long study period are a key strength of the study. A potential weakness is that the use of X-rays may be underestimated. For example, OHIP data does not include the costs paid above per-person limits, and chiropractors’ use of X-ray services provided by hospitals are not included.