Association of Frailty and Delirium with Hospitalization Outcomes Among Older Adults With Rheumatic Diseases

We investigated the association of frailty and delirium, both independently and in combination, with in-hospital mortality and nonroutine discharge among hospitalized older adults with rheumatic diseases.

We performed a retrospective study using data from the Nationwide Inpatient Sample, spanning 2016 to 2022. Adults aged ≥65 years with a diagnosis of select inflammatory rheumatic diseases were identified using International Code of Diseases, Tenth Revision (ICD-10) codes. Frailty was ascertained using the Hospital Frailty Risk Score (categorized into three levels: low [<5], moderate [5-15], and high [>15] frailty risk), and delirium was determined by ICD-10 codes. Multivariable logistic regressions adjusted for demographics and comorbidities were used to assess the association of delirium and frailty individually and combined with coprimary outcomes: in-hospital mortality and nonroutine discharge. Comorbidities were identified using the Elixhauser Comorbidity Index. Sensitivity analysis evaluated associations among patients with rheumatoid arthritis only and with varying case definitions of rheumatic diseases.

Among 938,595 weighted hospitalizations of older adults with rheumatic diseases (mean age 76.0 years, 74.6% female), 2.6% were classified as highly frail and 3.5% experienced delirium. Both delirium and high frailty independently increased the odds of in-hospital mortality (odds ratio [OR] 4.99, 95% confidence interval [CI] 4.16-5.99 and OR 6.80, 95% CI 5.45-8.48, respectively) and nonroutine discharge (OR 3.14, 95% CI 2.95-3.35 and OR 5.69, 95% CI 5.26-6.16, respectively). The combined presence of delirium and high frailty conferred the highest risk of mortality (OR 16.2, 95% CI 11.5-22.9) and nonroutine discharge (OR 11.1, 95% CI 8.78-14.0) and associations remained consistent across sensitivity analyses.

Among hospitalized older adults with rheumatic diseases, both frailty and delirium were independently linked to poorer outcomes, including higher in-hospital mortality and increased likelihood of discharge to a nonhome setting. Notably, patients with both conditions faced the greatest risk.