Association Between Charlson Comorbidity Index and Pressure Injury Stage: A Retrospective Cohort Study.

Pressure injuries (PIs) are a major clinical burden in patients with multiple comorbidities. The Charlson Comorbidity Index (CCI) is a validated comorbidity measure; however, its quantitative association with PI severity remains poorly characterised. To evaluate the association between CCI scores and PI stage, and to identify individual CCI component diseases independently associated with higher PI stage. This retrospective cohort study included 454 PI patients at a tertiary university hospital (July 2023-December 2025). PI severity was classified into stages 1-4. Both the original and updated CCI were calculated from comorbidities only, without the Charlson age adjustment. Ordinal logistic regression assessed associations between CCI and PI stage, adjusting for age and sex. The median patient age was 73 years (range, 17-95); 63.2% were male. Stage 2 PIs were most prevalent (70.5%). Each 1-point increase in original CCI was associated with 1.10-fold higher odds of a more advanced PI stage (95% CI: 1.02-1.20; p = 0.015) after adjusting for age and sex. Among individual CCI components, rheumatic disease (OR = 2.20; 95% CI: 1.04-4.65; p = 0.039) and hemiplegia/paraplegia (OR = 1.72; 95% CI: 1.07-2.77; p = 0.024) were independently associated with higher PI stage; moderate-to-severe renal disease showed an association of similar direction that did not reach statistical significance (OR = 1.63; 95% CI: 0.99-2.69; p = 0.056). A higher CCI was associated with higher PI severity in this cohort, although the effect size was modest. In a mutually adjusted multi-variable model, rheumatic disease and hemiplegia/paraplegia were independently associated with higher PI stage. These associations are observational and require prospective confirmation before any clinical application can be considered.