Patients suffering from obstructive sleep apnea (OSA) experience chronic sleep disturbances and desaturation, factors that have been associated with postoperative delirium and that can be aggravated after anesthesia for complex procedures. We investigated whether OSA is associated with delirium after anesthesia, and whether this association is modified by procedural complexity.
Hospitalized patients ≥60 years who underwent general anesthesia or procedural sedation for procedures of moderate-to-high complexity between 2009 and 2020 at a tertiary health care network in Massachusetts were included. The primary exposure was OSA, defined based on International Classification of Diseases (Ninth/Tenth Revision, Clinical Modification) (ICD-9/10-CM) diagnostic codes, structured nursing interviews, anesthesia alert notes, and a validated risk score (BOSTN [body mass index, observed apnea, snoring, tiredness, and neck circumference]). The primary end point was delirium within 7 days after the procedure. Multivariable logistic regression and effect modification analyses adjusted for patient demographics, comorbidities, and procedural factors were applied.
A total of 46,352 patients were included, of which 1694 patients (3.7%) developed delirium, 537 (3.2%) with OSA, and 1,157 (4.0%) without OSA. In adjusted analyses, OSA was not associated with postprocedural delirium in the overall cohort (adjusted odds ratio [ORadj], 1.06; 95% confidence interval [CI], 0.94–1.20; P = .35). However, a high procedural complexity modified the primary association (P value for interaction = .002). OSA patients had a higher risk of delirium after high-complexity procedures (≥40 work relative value units) such as cardiac (ORadj, 1.33; 95% CI, 1.08–1.64; P = .007, P value for interaction = .005) or thoracic surgery (ORadj, 1.89; 95% CI, 1.19–3.00; P = .007, P value for interaction = .009), but no increased risk after moderate complexity procedures, including general surgery (ORadj, 0.86; 95% CI, 0.55–1.35; P = .52).
Compared to non-OSA patients, a history of OSA is associated with a higher risk after high-complexity procedures such as cardiac or thoracic surgery but not after procedures of moderate complexity.