Health care resource use measured at discharge following CEA increases with age. Length of stay after CEA increases independently per decade starting at 70–79 years. Age dichotomized at 80, a typical age cut-off for high surgical risk, was also associated with increased post-operative length of stay, hospital costs and discharge to a SNF. In addition to age, comorbid conditions also increased health care utilization. However, increased health care resource use was not due to increased post-operative stroke in octogenarians.
We confirmed an association between age dichotomized at 80 years and in-hospital mortality.[8
] We found no significant association between age per decade or age dichotomized at 80 years and in-hospital post-operative stroke. This finding is consistent with an analysis of the 2005 NIS which also failed to identify an association of age, when divided into three levels (<60, 60–69, >70), and post-operative stroke.[5
] Lastly, a systematic review showed no increase in peri-operative stroke with increasing age.[9
] There was no association between age and the combined endpoint of in-hospital post-operative stroke or mortality. This analysis extends an observation that stroke or MI rates after CEA were higher in black subjects by demonstrating greater in-hospital resource use among those of non-white race.[10
Disease etiology may explain the u-shaped relationship between the length of stay from procedure to discharge and age. Carotid artery disease at younger ages may represent extreme atherosclerosis, familial hypercholesterolemia, or thrombus evacuation. Previously, individuals <50 years who underwent CEA were more likely to be smokers, have low HDL levels or consume alcohol.[11
] However, the increased time from procedure to discharge for 30–39 year olds compared to the 60–69 age group did not reach statistical significance ().
The data have the following limitations. The outcomes analysis is limited to the duration of the hospital stay. Use of 997.02 as the ICD-9 code for post-operative stroke, or codes for tobacco use may not be consistent between hospitals, thus in-hospital post-operative stroke may be under-represented. This analysis does not account for 30-day morbidity and mortality or duration of SNF admission. Analyzing hospital charges is not an accurate reflection of the cost to the health care system. We compensated for this shortcoming using cost-to-charge ratios. Hospital payments reflect operating and capital costs better than charges. Two similar hospitals based on location, size and teaching status may have radically different charges but receive similar Medicare payments as cost-to-charge ratios ranged from 19.9% to 95.8%.
The proportion age of 80 and older discharged to SNFs is intriguing. The percent of subjects admitted from such a facility did not vary with age and neither did the post-operative stroke rate. For those subjects age 80–98: 4.3% had an infarct yet were considered healthy enough for CEA; 1% had a post-operative stroke; and <1% came from a SNF. Assuming no overlap, this 5.3% did not equal the 9.7% of subjects that were discharged to a SNF. The increased odds of discharge to a SNF were independent of comorbidities, post-operative stroke, symptom status and admission source. On the other hand, over 90% of the procedures were for asymptomatic stenosis, regardless of age. An additional 4.1% of subjects age 80 and older compared to younger subjects (9.8% versus 5.7%, respectively) were discharged with home health care. Thus, reinforcing the question of why was discharge disposition different for older subjects?
The increased likelihood of discharge to an SNF for subjects ≥80 years of age reflects some type of increased post-operative morbidity or pre-existing health condition that could not be identified by this analysis. Moreover, ACST illustrated that older individuals, defined by an age cut-off of 75 years (n=650 subjects ≥75), would not likely benefit from immediate CEA.[13
] AAN guidelines reflect this position, recommending asymptomatic CEA for those 40–75 years.[14
] Possible explanations for these findings may include that stroke severity, postoperative myocardial infarction or other hospital acquired conditions increase with age. Stroke severity was not part of the NIS and could not be analyzed. Nevertheless, the potential for increased morbidity must be addressed with octogenarians considering prophylactic endarterectomy for asymptomatic stenosis.
Age is associated with increased health care resource use following CEA, including longer length of stay, higher costs and increased likelihood of being discharged to a SNF. Resource planning must ensure sufficient hospital beds for aging sick populations, sufficient skilled nursing or intermediate care beds, sufficient home health care and sufficient dollars for operating costs to meet the needs of an aging population.