The impact of diabetes mellitus on outcomes of endoscopic sinus surgery: A nested case-control study

Background: Given the immune impairment associated with diabetes mellitus (DM), its impact on chronic rhinosinusitis (CRS) is a potentially relevant concern; however, it has not been well-studied. A single retrospective study reported worse postoperative quality of life outcomes in DM patients with CRS. Our study evaluated the effect of comorbid DM on outcomes of endoscopic sinus surgery (ESS) using a prospective study design. Methods: Using a multicentered, prospective cohort of patients (n = 437) undergoing ESS for recalcitrant CRS, a nested case-control comparison was performed between 20 adult DM patients (cases) and 20 non-DM patients (controls), matched 1:1 for age and Lund-Mackay computed tomography (CT) scores. Outcome measures included 22-item Sinonasal Outcome Test (SNOT-22), Rhinosinusitis Disability Index (RSDI), Patient Health Questionnaire (PHQ-2), and Brief Smell Identification Test (BSIT). Results: Mean follow-up was similar between cases (mean ± standard deviation: 12.6 ± 6.0 months) and controls (12.9 ± 5.9 months; p = 0.862). All preoperative scores were statistically equivalent between DM and non-DM cohorts. Both cohorts showed significant post-ESS improvement in SNOT-22 (p = 0.001) and RSDI scores (p < 0.001), and no significant change in PHQ-2 or BSIT scores. The magnitude of score changes was statistically equivalent between the 2 cohorts for all outcome measures with no differences in postoperative score changes between insulin-dependent DM patients and those managed by oral hypoglycemics or dietary restriction (p ≥ 0.444). Conclusion: DM patients with CRS experience similar degrees of symptomatic benefit from ESS compared to controls. Insulin dependence does not appear to adversely affect surgical outcome but a larger cohort would better assess the effect of DM type and control on surgical outcomes in CRS.