Pyroptosis Endotypes and Malnutrition in Older Adults with Community-Acquired Pneumonia

14 Apr 20264 min read0 viewsJournal Feed

GIST

BackgroundDespite their disproportionately high mortality from community-acquired pneumonia (CAP), older adults remain understudied regarding inflammasome-mediated cell death pathways. We sought to determine whether distinct pyroptosis activation patterns exist in this population and how nutritional status modifies their prognostic impact.MethodsThis retrospective cohort study enrolled 282 patients aged ≥75 years hospitalized for CAP.

We quantified circulating pyroptosis effectors (gasdermin D [GSDMD], NLRP3, caspase-1) and assessed nutritional status using the Mini Nutritional Assessment-Short Form (MNA-SF). K-means clustering identified biological endotypes; generalized additive models (GAMs) characterized nonlinear biomarker-mortality relationships.

The primary endpoint was 28-day all-cause mortality.ResultsThree pyroptosis endotypes emerged with markedly divergent outcomes: hyper-pyroptotic (n=73; mortality 57.5%), intermediate-pyroptotic (n=128; mortality 10.2%), and hypo-pyroptotic (n=81; mortality 1.2%). The hyper-pyroptotic endotype was characterized by severe malnutrition (48.2% with MNA-SF ≤7) and elevated cytokines (median IL-6: 98.4 pg/mL).

GAM analysis revealed threshold-dependent, nonlinear relationships—mortality risk escalated sharply when GSDMD exceeded 3.5 ng/mL but showed attenuation at extreme values. Notably, two-dimensional analyses demonstrated supra-additive risk in patients with concurrent nutritional compromise and pyroptosis activation.

Clinical Editorial

Study design and population

Retrospective cohort of 282 patients aged 75 years or older hospitalized for community-acquired pneumonia (CAP).
Assessed circulating pyroptosis effectors (gasdermin D [GSDMD], NLRP3, caspase-1) and nutritional status via Mini Nutritional Assessment-Short Form (MNA-SF).
Endotyping employed K-means clustering; nonlinear biomarker–mortality relationships were explored with generalized additive models (GAMs).
Primary outcome: 28-day all-cause mortality.

Biological endotypes and associated outcomes

Three pyroptosis endotypes emerged:
Hyper-pyroptotic (n=73): mortality 57.5%.
Intermediate-pyroptotic (n=128): mortality 10.2%.
hypo-pyroptotic (n=81): mortality 1.2%.
The hyper-pyroptotic group exhibited notable malnutrition (48.2% had MNA-SF ≤7) and elevated inflammatory signaling (median IL-6 98.4 pg/mL).

Nonlinear relationships and interaction with nutrition

GAM analyses demonstrated threshold-dependent, nonlinear associations between markers and mortality.
Mortality risk rose sharply when GSDMD exceeded 3.5 ng/mL but attenuated at extreme biomarker values.
Two-dimensional analyses indicated supra-additive mortality risk in patients with both nutritional compromise and pyroptosis activation, suggesting effect modification by nutritional status.

Prognostic implications and comparative performance

An integrated prognostic model combining pyroptosis markers and clinical data achieved an AUC of 0.898 (95% CI: 0.847–0.943), outperforming the Pneumonia Severity Index alone (AUC 0.793; P<0.001).
The model demonstrated superior net benefit across clinically relevant decision thresholds (10–30%).

Limitations and uncertainties

The study is retrospective and based on a single older adult CAP cohort; generalizability to other populations is not established.
Specific numeric interaction effects and all potential confounders are not fully delineated in the summary provided.

Context and conclusions

The findings identify biologically distinct pyroptosis endotypes in geriatric CAP and indicate that malnutrition amplifies the prognostic relevance of pyroptosis markers.