How does chronic endocrine disease affect cost in spine surgery?

Previous research has suggested that increases in length of stay and hospital cost in patients undergoing spine surgery can be due to comorbidities, especially diabetes mellitus. To study how endocrine comorbidities impact spine surgery cost, we conducted the further analysis.

We reviewed the charts of 787 patients operated between 2005 and 2008 and their treatment cost. Patients underwent one of three of the most common types of spine surgery: lumbar microdiskectomy (N = 237), anterior cervical decompression and fusion (N = 339), and lumbar decompression and fusion (N = 211). Patients were 14 to 92 years of age (mean 54.5 years), nearly equally divided by gender and mostly white. Demographics, body mass index, and comorbidities were studied versus length of stay and hospital charges. Data were analyzed using the Mann-Whitney and Pearson χ(2) tests with the help of the SPSS v16 software.

Among the 653 patients who had their glycosylated hemoglobin (HbA1c) level measured, 32.5% had an HbA1c level ≥6.1% and 4.3% had high HbA1c level and hypothyroidism. These two comorbidities increased with age. Cost analysis showed that in the lumbar decompression and fusion group, length of stay and hospital cost significantly increased with these comorbidities. Without HbA1c elevation or hypothyroidism, the average length of stay for lumbar decompression and fusion patients was 5 days. This increased to 6 days with hypothyroidism. With both comorbidities the average length of stay increased to 8 days (P < .01). Regarding hospital cost, without these comorbidities the average was approximately $52,449. With elevated HbA1c the cost increased to $56,176 and with hypothyroidism to $63,278 (P < .01 and P < .05, respectively). When both comorbidities were present the average hospital cost was $71,352. It was also noted that 89.7% of the patients with hypothyroidism were women. Cost and length of stay increased with age in the female lumbar decompression and fusion group. In addition, there was a surge in length of stay and cost in the ≥70-year-old female group with hypothyroidism undergoing anterior cervical decompression and fusion.

HbA1c elevation and hypothyroidism have an additive effect on hospital cost in lumbar decompression and fusion female patients. The finding of a surge in hospital cost parameters in elderly female hypothyroid patients undergoing surgery on their cervical spine needs more investigation.