Incidence and risk factors for pneumonia following anterior cervical decompression and fusion procedures: an ACS-NSQIP study

Background context: Postoperative pneumonia has important clinical consequences for both patients and the health-care system. Few studies have examined pneumonia following anterior cervical decompression and fusion (ACDF) procedures.

Purpose: This study aimed to determine the incidence and risk factors for development of pneumonia following ACDF procedures.

Study design/setting: A retrospective cohort study of data collected prospectively by the American College of Surgeons National Surgical Quality Improvement Program was carried out.

Patient sample: This study comprised 11,353 patients undergoing ACDF procedures during 2011-2013.

Outcome measures: The primary outcome was diagnosis of pneumonia in the first 30 postoperative days.

Methods: Independent risk factors for the development of pneumonia were identified using multivariate regression. Readmission rates were compared between patients who did and did not develop pneumonia using multivariate regression that adjusted for all demographic, comorbidity, and procedural characteristics.

Results: The incidence of pneumonia was 0.45% (95% confidence interval=0.33%-0.57%). In the multivariate analysis, independent risk factors for the development of pneumonia were greater age (p<.001), dependent functional status (relative risk [RR]=5.3, p<.001), chronic obstructive pulmonary disease (RR=4.4, p<.001), and greater operative duration (p=.020). Patients who developed pneumonia following discharge had a higher readmission rate than other patients (72.7% vs. 2.4%, adjusted RR=24.5, p<.001). In total, 10.2% of all readmissions were caused by pneumonia.

Conclusions: Pneumonia occurs in approximately 1 in 200 patients following ACDF procedures. Patients who are older, are functionally dependent, or have chronic obstructive pulmonary disease are at greater risk. These patients should be counseled, monitored, and targeted with preventative interventions accordingly. Greater operative duration is also an independent risk factor. Approximately three in four patients who develop pneumonia following hospitalization for ACDF procedures are readmitted. This elevated readmission rate has implications for bundled payments and hospital performance reports.