Variation in costs among surgeons for lumbar spinal stenosis

Background Context

Lumbar spinal stenosis is a common condition in the elderly for which costs vary substantially by region. Comparing differences between surgeons from a single institution, thereby omitting regional variation, could aid in identifying factors associated with higher costs and individual drivers of costs. The use of decision aids (DAs) has been suggested as one of the possible tools for diminishing costs and cost variation.

Purpose

(1) To determine factors associated with higher costs for treatment of spinal stenosis in the first year after diagnosis in a single institution; (2) to find individual drivers of costs for providers with higher costs; and (3) to determine if the use of DAs can decrease costs and cost variability.

Study Design

Retrospective cohort study.

Patient Sample

A total of 10,858 patients in 18 different practices diagnosed with lumbar spinal stenosis between January 2003 and July 2015 in three associated hospitals of a single institution.

Outcome Measures

Mean cost for a patient per provider in US dollars within 1 year after diagnosis of lumbar spinal stenosis.

Methods

We collected all diagnostic testing, office visits, injections, surgery, and occupational or physical therapy related to lumbar spinal stenosis within 1 year after initial diagnosis. We used multivariable linear regression to determine independent predictors for costs. Providers were grouped in tiers based on mean total costs per patient to find drivers of costs. To assess the DAs effect on costs and cost variability, we matched DA patients one-to-one with non-DA patients.

Results

Male gender (β 0.10, 95% confidence interval [CI] 0.05–0.15, p<.001), seeing an additional provider (β 0.77, 95% CI 0.69–0.86, p<.001), and having an additional spine diagnosis (β 0.79, 95% CI 0.74–0.84, p<.001) were associated with higher costs. Providers in the high cost tier had more office visits (p<.001), more imaging procedures (p<.001), less occupational or physical therapy (p=.002), and less surgery (p=.001) compared with the middle tier. Eighty-two patients (0.76%) received a DA as part of their care; there was no statistically significant difference between the DA group and the matched group in costs (p=.975).

Conclusions

Male gender, seeing an additional provider, and having an additional spine diagnosis were independently associated with higher costs. The main targets for cost reduction we found are imaging procedures and number of office visits. Decision aids were not found to affect cost.