Association of Inpatient Diabetes Specialist Consultation with Clinical Outcomes in Patients with Diabetes Hospitalized for Lower Respiratory Tract Infections: A Retrospective Cohort Study.

Background

Diabetes mellitus (DM) is associated with an increased susceptibility to lower respiratory tract infections (LRTIs) and more severe clinical courses, including prolonged hospitalization and increased mortality. During LRTI-related hospitalizations, clinical management often prioritizes the acute respiratory condition, potentially under-recognizing DM-related multimorbidity. We evaluated whether inpatient diabetes specialist consultation is associated with improved outcomes in this high-risk population.

Methods

We conducted a retrospective cohort study of 677 adults with DM admitted for LRTI. Specialist consultation was defined as involvement of an endocrinology and/or diabetes nurse specialist during index hospitalization. Outcomes included length of hospital stay (LOHS) and 90-day mortality. Multivariable zero-truncated negative binomial regression (LOHS) and logistic regression (mortality) were adjusted for age, sex, Charlson Comorbidity Index (CCI), National Early Warning Score (NEWS), and pre-admission insulin use, hypoglycemic events, and admission laboratory parameters. Inverse probability of treatment weighting (IPTW) based on propensity scores was performed as a sensitivity analysis.

Results

Among 677 patients, 84 (12.4%) received diabetes specialist consultation. Patients receiving consultation had lower unadjusted 90-day mortality (4.8% vs. 17.5%, p = 0.001) but longer median LOHS (9 vs. 7 days, p < 0.001). After multivariable adjustment, diabetes specialist consultation was associated with lower 90-day mortality (OR 0.23, 95% CI 0.08-0.68, p = 0.008) and longer LOHS (IRR 1.27, 95% CI 1.12-1.44, p < 0.001). The results were consistent in IPTW sensitivity analyses.

Conclusions

In this retrospective cohort of patients with DM hospitalized for LRTIs, inpatient diabetes specialist consultation was associated with lower 90-day mortality, but longer hospital stay. These findings suggest that structured inpatient diabetes specialist involvement may contribute to improved medium-term outcomes in high-risk multimorbid patients. Prospective studies are required to determine causality and evaluate the impact of consultation timing and referral strategies.