The effect of diabetes mellitus on 30-day outcomes following single-level open lumbar microdiscectomy: An aged-matched case-control study

BACKGROUND: Diabetes mellitus (DM) is a known risk factor for post-surgical complications. However, few reports specifically study lumbar spine surgical outcomes in diabetics. The purpose of this study was to assess 30-day outcomes in patients with DM undergoing single-level open lumbar microdiscectomy (oLMD). METHODS: Aretrospective case control study on patients with DM undergoing between 2001 and 2012. Patients who underwent a minimally invasive approach, repeat discectomy, or multilevel surgery were excluded. One hundred and twenty-six patients were age-matched with 126 non-diabetic controls. Outcomes assessed included length of stay (LOS), postoperative urinary retention (UR), total morbidity, infection, postoperative radiculitis, 30-day re-admissions and emergency department visits, and pain status at discharge and at 30 days. Categorical variables were evaluated with Pearson's χ² tests. Student's t-tests were used to evaluate continuous variables. Univariate logistic regression was used to evaluate strength of association of DM with outcome variables. RESULTS: Mean LOS was significantly higher in diabetic patients (1.9 vs. 1.4 days, P<0.0001). DM was associated with increased morbidity (P=0.009, OR=3.3, CI: 1.3-9.5) and UR(P<0.0001, OR=8.2, CI: 3.4-24.8). No differences were found in 30-day readmission rates or emergency department visits, pain status at discharge and at 30 days, or postoperative radiculitis. CONCLUSIONS: Overall, short-term outcomes are worse in patients with DM. Following single-level oLMD, DM is associated with longer hospital stays, UR, and increased morbidity. These short term outcomes consequently lead to an overall increase in hospital costs.