Researchers analyze spine surgery patients' existing comorbdities in relationship to hospital stay, costs

It is estimated that between 75 and 85 percent of all Americans will suffer from low back pain and/or neck pain at some point in their lives. An estimated 12 million Americans suffer from degenerative disc disease, with over one million patients undergoing surgery each year. The cost of treating back pain is currently estimated at more than $100 billion annually in the U.S. Many patients with back pain have comorbidities that impact spine surgery. Comorbidity is the presence of one or more disorders (or diseases) in addition to a primary disease or disorder; or the effect of such additional disorders or diseases.

Previous research has suggested that among spine surgery patients, comorbidities may increase the length of stay and hospital cost. "This issue is of substantial importance in an era of economic restraint and frequent operative spine procedures. In order to study the prevalence of comorbidities among patients undergoing costly spine surgery and verify the impact of these factors on length of stay and hospital cost, an in-depth study was conducted on nearly 600 patients undergoing spine surgery at our institution," stated Joe S. Robinson Jr., MD, FACS, senior author of the study.

Researchers at the Georgia Neurosurgical Institute in Macon, Ga., analyzed spine surgery patients' existing comorbdities in relationship to hospital stay and costs. The results of this study, Comorbidities in Spine Surgery Patients and Impact on Length of Stay and Hospital Cost, will be presented by Dr. Robinson, 4:44 to 4:51 pm, Tuesday, May 4, 2010, during the 78th Annual Meeting of the American Association of Neurological Surgeons in Philadelphia. In addition to lead author Muhammad S. Walid, MD, PhD, co-authors are Edward R. M. Robinson, BA, and Joe S. Robinson III, BA.

Fifteen major comorbidities and age-adjusted Charlson Comorbidity Index scores were retrospectively analyzed in 578 randomly selected patients who underwent spine surgery from 2005-2007 at the Georgia Neurosurgical Institute. Treatment costs (hospital charges) and length of hospital stay were analyzed.

Three common types of spine surgery were included:

•Lumbar microdiskectomy: 154
•Anterior cervical decompression and fusion: 297
•Lumbar decompression and fusion: 127

Patient demographics

•Age of patients: 21-92 with 41 percent over age 60
•Equal number of males and females
•Caucasians: 78 percent, African Americans: 21 percent

Comorbidity patient demographics

•Hypertension: 78 percent
•History of diabetes mellitus or an elevated glycosylated hemoglobin: 35 percent
•High cholesterol: 31 percent
•Coronary heart disease: 20 percent
•History of hypothyroidism: 10 percent
•History of chronic obstructive pulmonary disease: 8 percent
•An active malignant disease: 2.5 percent
•Epilepsy: 1.6 percent
•Rheumatoid arthritis or lupus erythematosis: 1.4 percent
•Advanced or chronic renal disease: 1.4 percent
•Additionally, 25.4 percent of all patients were on antidepressants.

The study yielded the following results:

•Half of the patients had a Charlson Index Score of zero and 11.3 percent had a ≥5 score. Charlson Index correlated with length of stay>

•Comorbidities had an additive effect on length of stay and hospital cost in the lumbar decompression and fusion patients:

   -The average hospital cost in patients without diabetes mellitus/elevated HbA1c or hypothyroidism: $46,360

   -The average hospital cost in patients with diabetes mellitus/elevated HbA1c or hypothyroidism: $54,228

   -The average hospital cost in patients with both cormorbidities: $61,221

   -The average hospital cost in patients with diabetes mellitus/elevated HbA1c, hypothyroidism and depression: $68,203.

Comorbidities also were tied to an increase in Medicare costs (2008 figures). The cost of DRG 460 and 459 Spinal Fusion was analyzed. In patients with no comorbidities, compensation was $17,131.42. In patients with major complication or comorbidity, compensation was $23,915.70.

"It is important that strategies are devised which include appropriate preoperative screening to help contain comorbidity-related hospital costs. With a large number of older patients undergoing spine surgery every year and the government struggling to contain Medicare costs, the presence of comorbidities is an issue that needs to be taken into consideration prior to surgery," remarked Dr. Walid.

"Further, compensation to physicians must take into account the presence of comorbidities, so that reimbursement amounts are not arbitrarily established," concluded Dr. Robinson.