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The Spine Blog

Friday, March 9, 2018

Do depressed patients do worse after lumbar decompression?

Multiple studies have suggested that depressed patients do worse following spine surgery.1 Prior investigations have defined depression in different ways, including patient self-report and scores on various health surveys. While the spine community generally agrees that depression is a predictor of worse outcomes, no spine surgery study has used the PROMIS depression questionnaire to diagnose depression. In order to assess the PROMIS depression questionnaire as a predictor of spine surgery outcomes, Merrilll and colleagues evaluated baseline and 6-month post-operative outcomes including the PROMIS physical function, pain, and depression inventories and the Oswestry Disability Index (ODI) in 111 patients undergoing lumbar laminectomy. The patients were classified as depressed (PROMIS depression score > 50) or non-depressed (depression score < 50) based on their baseline PROMIS depression score. Note that this measure has a mean value of 50 in the general population. Not surprisingly, the depressed patients had significantly worse baseline and 6 month scores on all outcome measures. In an analysis that did not control for baseline differences, the depressed patients actually had a greater degree of improvement on the PROMIS physical function score and depression score compared to the non-depressed group. There were no differences in change scores on the other outcome measures. In a subgroup analysis comparing outcomes between patients with depression scores of 50-60 (mild depression) and over 60 (more severe depression), the severity of depression had no effect on outcomes.

This is an interesting study as it uses the PROMIS depression score as a way to diagnose depression. One concern with this paper is that it classified depression as having a score above the mean, indicating that 50% of the population would be diagnosed with depression using this standard. While that seems like a low bar to classify depression, their analysis demonstrated that severity of depression did not affect outcomes. An important finding is that depressed patients improved to a similar or greater degree than non-depressed patients, though their absolute scores were worse. This makes it clear that depressed patients do benefit from surgery, though patients and providers should have reasonable expectations about their likely outcomes. These findings have some similarities to the Spine Patient Outcomes Research Trial (SPORT), which demonstrated that the treatment effect of surgery (the difference in improvement between surgical and non-operative patients) is similar for depressed and non-depressed patients.2-4 SPORT defined depression as an SF-36 mental component score of < 35, a more stringent definition than that used in the current study. The SPORT analysis also controlled for baseline ODI score, and that analysis showed a smaller change score for the depressed patients. The current study showed similar or greater change scores for the depressed patients, but this is likely due to their worse baseline scores, which were not controlled for in the current analysis. This paper demonstrates that the PROMIS depression score may be a reasonable tool to screen for depression in the spinal stenosis population. The appropriate cut-off for defining depression in this population remains unknown. The real question is whether or not treating depression pre-operatively improves post-operative outcomes. Future studies will have to address that.

Adam Pearson, MD, MS
Associate Web Editor

 

REFERENCES

1.            Slover J, Abdu WA, Hanscom B, Weinstein JN. The impact of comorbidities on the change in short-form 36 and oswestry scores following lumbar spine surgery. Spine (Phila Pa 1976) 2006;31:1974-80.

2.            Pearson A, Lurie J, Tosteson T, et al. Who should have surgery for an intervertebral disc herniation? Comparative effectiveness evidence from the spine patient outcomes research trial. Spine 2012;37:140-9.

3.            Pearson A, Lurie J, Tosteson T, Zhao W, Abdu W, Weinstein JN. Who should have surgery for spinal stenosis? Treatment effect predictors in SPORT. Spine 2012;37:1791-802.

4.            Pearson AM, Lurie JD, Tosteson TD, Zhao W, Abdu WA, Weinstein JN. Who should undergo surgery for degenerative spondylolisthesis? Treatment effect predictors in SPORT. Spine (Phila Pa 1976) 2013;38:1799-811.