Risk Factors for Community-Acquired Pneumonia in Adults: A Systematic Review of Observational Studies
Bibliographic record
Abstract
We performed a systematic review of the literature to establish conclusive evidence of risk factors for community-acquired pneumonia (CAP). Observational studies (cross-sectional, case-control, and cohort studies) the primary outcome of which was to assess risk factors for CAP in both hospitalized and ambulatory adult patients with radiologically confirmed pneumonia were selected. The Newcastle-Ottawa Scale specific for cohort and case-control designs was used for quality assessment. Twenty-nine studies (20 case-control, 8 cohort, and 1 cross-sectional) were selected, with 44.8% of them focused on elderly subjects ≥65 years of age and 34.5% on mixed populations (participants' age >14 years). The median quality score was 7.44 (range 5-9). Age, smoking, environmental exposures, malnutrition, previous CAP, chronic bronchitis/chronic obstructive pulmonary disease, asthma, functional impairment, poor dental health, immunosuppressive therapy, oral steroids, and treatment with gastric acid-suppressive drugs were definitive risk factors for CAP. Some of these factors are modifiable. Regarding other factors (e.g., gender, overweight, alcohol use, recent respiratory tract infections, pneumococcal and influenza vaccination, inhalation therapy, swallowing disorders, renal and liver dysfunction, diabetes, and cancer) no definitive conclusion could be established. Prompt assessment and correction of modifiable risk factors could reduce morbidity and mortality among adult CAP patients, particularly among the elderly.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.010 | 0.041 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.008 | 0.007 |
| Bibliometrics | 0.013 | 0.015 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".