Baseline nutritional-inflammatory status, rather than in-hospital biochemical deterioration, is associated with swallowing recovery in patients with pneumonia: A retrospective cohort study

Background & aims Dysphagia is common in patients hospitalized for pneumonia and is closely associated with nutritional status. Although poor nutritional status at admission is associated with adverse outcomes, the relationship between short-term in-hospital changes in biochemical nutritional-inflammatory indices and swallowing recovery remains unclear and is difficult to evaluate because such changes are defined using discharge measurements, whereas recovery often occurs earlier. We examined baseline nutritional-inflammatory status as the primary exposure and evaluated longitudinal swallowing trajectories according to eventual in-hospital biochemical deterioration. Methods This retrospective, single-center cohort study included 199 adult patients hospitalized for pneumonia. The Functional Oral Intake Scale (FOIS; range 1-7) was assessed at admission, weekly thereafter, and at discharge. Modified Controlling Nutritional Status (mCONUT; range 0-12) scores were calculated at admission and discharge. The primary exposure was baseline mCONUT, and the primary outcome was time to first achievement of FOIS ≥ 4. The Cox analysis was restricted to patients with baseline dysphagia (FOIS < 4; n = 113, 61 events) and adjusted for baseline covariates. A linear mixed-effects model using repeated FOIS measurements across five timepoints (n = 199 patients, 762 observations) examined whether the rate of FOIS change differed according to eventual mCONUT-worsening status. Results Higher baseline mCONUT showed a directionally consistent association with delayed achievement of FOIS ≥ 4, although the association did not reach conventional statistical significance (adjusted hazard ratio 0.88 per 1-point increase, 95% confidence interval 0.77-1.01, p = 0.068). FOIS improved significantly over time (β = +0.060/day, p < 0.001). Higher baseline mCONUT (β = -0.142, p = 0.036) and greater pre-hospital frailty (β = -0.379, p < 0.001) were associated with lower longitudinal FOIS levels. No significant time × mCONUT-worsening interaction was observed (β = +0.009, p = 0.537), providing no evidence that the rate of FOIS change differed according to eventual in-hospital mCONUT-worsening status. Conclusion Higher baseline mCONUT showed a directionally consistent association with delayed swallowing recovery and was associated with lower longitudinal FOIS levels, while greater pre-hospital frailty was also associated with lower FOIS levels over time. No statistically significant difference in the rate of FOIS change was observed according to eventual in-hospital mCONUT-worsening status. Because in-hospital mCONUT change was defined using discharge measurements, associations with early swallowing recovery should be interpreted cautiously owing to temporal-ordering limitations.