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

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).A retrospective 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.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.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.