The occurrence of Hospital-Acquired Pneumonia is independently associated with elevated Stress Hyperglycaemia Ratio at admission but not elevated blood glucose

Background: The association between stress-induced hyperglycaemia (SIH) and increased infection rates in hospitalised subjects is well-known. It is less clear if SIH at admission independently drives new-onset infections. We assessed the relationship between early exposure at admission to both the Stress Hyperglycaemia Ratio (SHR) and Blood Glucose (BG) with Hospital-Acquired Pneumonia (HAP). 

Methods: This observational retrospective study included those with length-of-stay > 1 day, BG within 24 h of admission and recent haemoglobin A1c. SIH was defined as BG ≥ 10 mmol/L, or SHR ≥ 1.1, measured at both admission and as a 24-hour maximum. Multivariable analyses were adjusted for length-of-stay, age, mechanical ventilation, and chronic respiratory disease. 

Results: Of 5,339 eligible subjects, 110 (2.1%) experienced HAP. Admission SHR ≥ 1.1 was independently associated with HAP (OR 3.04, 95% CI 1.98–4.68, p < 0.0001) but not BG ≥ 10 mmol/L (OR 0.65, 95% CI 0.41–1.03, p = 0.0675). The association with SHR strengthened using maximum 24-hour values (OR 3.37, 95% CI 2.05–5.52, p < 0.0001) while BG ≥ 10 mmol/L remained insignificant (OR 0.96, 95% CI 0.63–1.46, p = 0.86). Of those experiencing HAP 40 (36.4%) occurred in subjects with no recorded BG ≥ 10 mmol/L but SHR ≥ 1.1. 

Conclusion: SIH at admission defined as SHR ≥ 1.1, but not the conventional marker of BG ≥ 10 mmol/L, was independently associated with the subsequent onset of HAP, commonly at BG < 10 mmol/L.