Wednesday, September 26, 2018 2:00 PM – 3:00 PM Increasing Value: Lumbar Spine Surgery: 67. The impact of diabetes mellitus on length of stay and direct hospital costs after minimally invasive transforaminal lumbar interbody fusion

Abstract

BACKGROUND CONTEXT Diabetes mellitus is one of the most prevalent medical conditions in the United States, with approximately 30 million patients diagnosed. Within the field of orthopedic surgery, diabetes has been well studied in regards to its effect on postoperative outcomes and complication incidence. In the subspecialty spine literature, the presence of diabetes as a comorbidity has been associated with an increased risk for acute postoperative complications, increased length of inpatient stay, and increased costs. However, the majority of these investigations have been performed in study populations undergoing heterogeneous mixtures of procedure types. Very few studies have investigated the effect of diabetes on inpatient length of stay or direct hospital costs in procedure-specific populations. PURPOSE To determine if the presence of diabetes mellitus as a comorbidity is associated with inpatient length of stay or direct hospital costs after minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). STUDY DESIGN/SETTING Retrospective analysis of a prospectively managed surgical database. PATIENT SAMPLE One hundred patients who underwent a primary, single-level MIS TLIF between 2008 and 2016. Patients were 1:1 propensity matched for presence of diabetes mellitus. OUTCOME MEASURES Perioperative variables, inpatient length of stay, direct hospital costs. METHODS A prospectively-maintained surgical registry of patients undergoing primary, single-level MIS TLIF for degenerative pathology between 2008 and 2016 was retrospectively reviewed. Diabetic and non-diabetic patients were propensity matched in a 1:1 fashion for age, gender, and comorbidity burden. An association between diabetic status and preoperative demographic or perioperative variables, including inpatient length of stay, was tested for using student's t test or chi-square analysis for continuous or categorical variables, respectively. Multivariate linear regression was used to test for an association between diabetic status and direct hospital costs. Statistical significance was set at p RESULTS After 1:1 propensity matching, 100 patients were included in this analysis. There were no significant differences in age, sex, body mass index, smoking status, or Charlson Comorbidity Index between propensity-matched patients with and without diabetes. In regards to length of stay, no significant differences existed between diabetic and non-diabetic groups (68.7 vs. 58.3 hours, p=.218). No other significant differences existed in other perioperative variables including operative time, intraoperative blood loss, or complication rate (p>.05 for each). Multivariate analysis indicated that diabetic status was not associated with differences in total direct hospital costs ($20428 vs. $20429, p=.792) or cost subcategories after MIS TLIF (p>.05 for each). CONCLUSIONS Diabetes mellitus was not associated with increased length of stay or direct hospital costs after single-level MIS TLIF. The reduced extent of operative exposure and tissue trauma in MIS TLIF may mitigate the risk of complications in diabetic patients, possibly preventing extensions in hospital stay length. Within the topic of spine surgery, further investigation of the effect of diabetes mellitus on perioperative and postoperative outcomes is required for procedure-specific cohorts. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.