The impact of preoperative glycated hemoglobin levels on outcomes in oral squamous cell carcinoma

Objectives This study aimed to investigate the association between preoperative glycated hemoglobin (HbA1c) levels and the treatment outcomes of oral cavity squamous cell carcinoma (OSCC). Methods Three hundred and fifty‐eight OSCC patients were consecutively enrolled between July 2004 and July 2016. Clinicopathological parameters and survival outcomes were analyzed following HbA1c stratification of 6.5% (HbA1c ≥ 6.5%: n = 74, 20.6%) and 7.0% (HbA1c ≥ 7.0%: n = 53, 14.8%). Results Higher HbA1c levels were associated with elevated body mass index, lower albumin levels, wider surgical margins, and prolonged hospital stays (HbA1c 6.5%: p = .001, .048, .030, .009, respectively; HbA1c 7.0%: p = .092, .032, .009, .015, respectively). Survival rates stratified by HbA1c 6.5% were as follows: locoregional recurrence‐free survival, p = .014; distant metastasis‐free survival, p = .013; second primary cancer‐free survival, p = .015; overall survival, p = .014; disease‐specific survival, p = .002 and HbA1c 7.0%: locoregional recurrence‐free survival, p = .013; distant metastasis‐free survival, p = .013; second primary cancer‐free survival, p = .014; overall survival, p = .015; disease‐specific survival, p = .004. Multivariate analyses identified HbA1c as an independent prognostic factor for overall and disease‐specific survival (HbA1c 6.5%: p = .014 and .002, respectively; HbA1c 7.0%: p = .036 and .013, respectively). Conclusions Oral squamous cell carcinoma patients with higher preoperative HbA1c levels had longer hospitalization and worse survival outcomes.