Comparison of the lumbar disc herniation patients randomized in SPORT to 6,846 discectomy patients from NSQIP: demographics, perioperative variables, and complications correlate well

Background context: The Spine Patient Outcomes Research Trial (SPORT) is a highly referenced clinical trial that randomized patients with lumbar pathology to receive surgery or continued conservative treatment.

Purpose: The purpose of this study was to compare the SPORT lumbar disc herniation cohort and an analogous cohort from the National Surgical Quality Improvement Program (NSQIP) database.

Study design/setting: This is a retrospective cohort study comparing a national database population to a randomized clinical trial.

Patient sample: Elective lumbar discectomies from NSQIP between 2010 and 2012 were used.

Outcome measures: Demographics were compared between the randomized SPORT cohorts (surgical and nonoperative) and NSQIP. Perioperative factors and complications were then compared between SPORT discectomy patients and NSQIP.

Methods: Using current procedural terminology and International Classification of Diseases, ninth revision codes, all elective lumbar discectomies from NSQIP between 2010 and 2012 were identified. Where possible based on the published data and variables available in each cohort, the two populations were compared.

Results: A total of 6,846 NSQIP discectomy patients were compared with the randomized SPORT surgical and nonoperative cohorts. Demographic comparisons showed that NSQIP patients were older (average age 48.2±14.5 years [mean±standard deviation] vs. 41.7±11.8 and 43.0±11.3 years, respectively [p<.001]) and had higher body mass index (29.6±6.2 kg/m(2) vs. 27.8±5.6 and 28.2±5.4 kg/m(2), respectively [p<.001]). No statistical differences existed for gender or race. Smoking status was not different between the SPORT nonoperative group and NSQIP but was higher in NSQIP compared with SPORT surgical patients (p=.020 by 7%). Comparisons of perioperative factors and complications between the SPORT surgical cohort and NSQIP showed no statistical difference in average operative time, length of stay, deep wound infections, wound dehiscence, total wound complications, or blood transfusions. Spine Patient Outcomes Research Trial superficial wound infection rates were higher than NSQIP (p=.029 by 1.4%). As expected, SPORT 1-year reoperation rates were higher than NSQIP 30-day rates (7% vs. 2%, p<.001).

Conclusions: Spine Patient Outcomes Research Trial lumbar disc herniation results are similar to those from a large national patient sample. Even statistically significant differences would be considered clinically similar. These findings support the generalizability of the SPORT lumbar disc herniation results.