Clinical features associated with occult pneumonia among older adults with community-acquired pneumonia: a descriptive retrospective study
- 1Department of General Practice, The Fifth Clinical Medical College of Henan University of Traditional Chinese Medicine (Zhengzhou People's Hospital), Zhengzhou, China
Abstract
Background: Pneumonia is a major global health burden and a substantial threat to older adults. Because pneumonia in this population may present insidiously without typical respiratory symptoms, occult pneumonia can be easily overlooked, resulting in delayed treatment and an increased risk of severe disease and death. This study aimed to identify clinical features associated with occult pneumonia.
Methods: We retrospectively reviewed the medical records of 334 older adults with pulmonary infections admitted to our hospital between January 2023 and January 2025. Patients were randomly assigned to a development cohort (n = 234) and an internal validation cohort (n = 100) at a 7:3 ratio. The development cohort comprised 80 patients with occult pneumonia and 154 with typical pneumonia. Univariate and multivariable logistic regression analyses were performed to identify factors independently associated with occult pneumonia.
Results: LASSO logistic regression with 5-fold cross-validation and backward-stepwise logistic regression identified five independent predictors of occult pneumonia: age ≥80 years (OR = 2.584, 95% CI: 1.350–4.948), diabetes mellitus (OR = 3.392, 95% CI: 1.696–6.782), cerebrovascular disease (OR = 2.116, 95% CI: 1.027–4.357), decreased appetite (OR = 4.982, 95% CI: 2.609–9.513), and WBC count (OR = 2.797, 95% CI: 1.290–6.067; all P < 0.05). The association with WBC count was positive and graded: WBC counts were higher in patients with occult than typical pneumonia (median 6.92 vs. 6.06 × 10⁹/L, P = 0.002), and in sensitivity analyses each 1 × 10⁹/L increase in WBC count was associated with an 18% increase in the odds of occult pneumonia (OR = 1.184, 95% CI: 1.051–1.334) without evidence of non-linearity (P = 0.920). The model achieved AUCs of 0.799 (95% CI: 0.739–0.854) in the development cohort and 0.799 (95% CI: 0.699–0.886) in the internal validation cohort. Calibration was assessed using the calibration intercept, slope, and Brier score, which indicated good agreement between predicted and observed probabilities.
Conclusion: Age ≥80 years, diabetes mellitus, cerebrovascular disease, decreased appetite, and WBC count were independently associated with occult pneumonia in older adults. These factors characterize the occult presentation phenotype and may help clinicians recognize occult pneumonia among older adults with CAP to support appropriate evaluation and management.
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BibTeX
@article{panpan2026clinical,
title = {{Clinical features associated with occult pneumonia among older adults with community-acquired pneumonia: a descriptive retrospective study}},
author = {Liu Panpan and Lei Manman and Qin Fufang},
journal = {Frontiers in Medicine},
year = {2026},
month = oct,
doi = {10.3389/fmed.2026.1966431},
url = {https://doi.org/10.3389/fmed.2026.1966431},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Clinical features associated with occult pneumonia among older adults with community-acquired pneumonia: a descriptive retrospective study
AU - Liu Panpan
AU - Lei Manman
AU - Qin Fufang
PY - 2026
DA - 2026/10/21
JO - Frontiers in Medicine
DO - 10.3389/fmed.2026.1966431
UR - https://doi.org/10.3389/fmed.2026.1966431
AB - Background: Pneumonia is a major global health burden and a substantial threat to older adults. Because pneumonia in this population may present insidiously without typical respiratory symptoms, occult pneumonia can be easily overlooked, resulting in delayed treatment and an increased risk of severe disease and death. This study aimed to identify clinical features associated with occult pneumonia. Methods: We retrospectively reviewed the medical records of 334 older adults with pulmonary infections admitted to our hospital between January 2023 and January 2025. Patients were randomly assigned to a development cohort (n = 234) and an internal validation cohort (n = 100) at a 7:3 ratio. The development cohort comprised 80 patients with occult pneumonia and 154 with typical pneumonia. Univariate and multivariable logistic regression analyses were performed to identify factors independently associated with occult pneumonia. Results: LASSO logistic regression with 5-fold cross-validation and backward-stepwise logistic regression identified five independent predictors of occult pneumonia: age ≥80 years (OR = 2.584, 95% CI: 1.350–4.948), diabetes mellitus (OR = 3.392, 95% CI: 1.696–6.782), cerebrovascular disease (OR = 2.116, 95% CI: 1.027–4.357), decreased appetite (OR = 4.982, 95% CI: 2.609–9.513), and WBC count (OR = 2.797, 95% CI: 1.290–6.067; all P < 0.05). The association with WBC count was positive and graded: WBC counts were higher in patients with occult than typical pneumonia (median 6.92 vs. 6.06 × 10⁹/L, P = 0.002), and in sensitivity analyses each 1 × 10⁹/L increase in WBC count was associated with an 18% increase in the odds of occult pneumonia (OR = 1.184, 95% CI: 1.051–1.334) without evidence of non-linearity (P = 0.920). The model achieved AUCs of 0.799 (95% CI: 0.739–0.854) in the development cohort and 0.799 (95% CI: 0.699–0.886) in the internal validation cohort. Calibration was assessed using the calibration intercept, slope, and Brier score, which indicated good agreement between predicted and observed probabilities. Conclusion: Age ≥80 years, diabetes mellitus, cerebrovascular disease, decreased appetite, and WBC count were independently associated with occult pneumonia in older adults. These factors characterize the occult presentation phenotype and may help clinicians recognize occult pneumonia among older adults with CAP to support appropriate evaluation and management.
SN - 2296-858X
ER -