Poorly controlled diabetes: Glycosylated hemoglobin (HA1c) levels >8% are the tipping point for significantly worse outcomes following hip fracture in the geriatric population

Abstract

The presence of diabetes has been associated with increased mortality risk after hip fracture, however, little has been published about the lab values of these diabetic patients and the role high labs play in morbidity and mortality. The purpose of this study is to quantify the severity of diabetes that is associated with worse outcomes in hip fracture patients. A consecutive series of 2430 patients >55 years old who sustained a hip fracture between October 2014-November 2021 were reviewed for demographics, hospital quality measures, and outcomes. Each patient with a diagnosis of diabetes mellitus (DM) was reviewed for hemoglobin-A1c (HA1c) and glucose values at admission. Univariable comparisons and multivariable regression analyses were conducted to assess the impact of diabetes and elevated lab values (HA1c) on outcomes such as hospital quality measures, inpatient complications, readmission rates, and mortality rates. 565 patients (23%) carried a diagnosis of diabetes mellitus at the time of their injury. Considerable demographic and comorbidity differences between diabetic and non-diabetic cohorts indicated that the diabetic cohort was less healthy. The diabetic cohort had longer hospitalizations, higher rates of minor complications, readmissions within 90-days, and mortality within 30-days/1-year. Stratification by HA1c levels found patients with a HA1c>8% had a significantly higher rate of major complications, and mortality at all time points (inpatient/30-day/1-year). Multivariable regression found HA1c>8% to be independently associated with a higher rate of inpatient/30-day/1-year mortality in comparison to a diagnosis of diabetes alone which was not independently significant. While all patients with DM experienced worse outcomes than those without, those with poorly controlled diabetes (HA1c>8%) at the time of hip fracture injury experienced poorer outcomes compared to those with well-controlled diabetes. Treating physicians must recognize these patients with poorly controlled DM at the time of arrival to adjust care planning and patient expectations accordingly.