Prevalence of opioid dependence in spine surgery patients and correlation with length of stay.

OBJECTIVE

We addressed the prevalence of opioid dependence (OD) in spine surgery patients and its correlation with length of stay (LOS) as the most important determinant of hospital cost.

METHODS

The study took place at Georgia Neurosurgical Institute and the Medical Center of Central Georgia between March 2006 and January 2007. A prospective convenience sample of 150 spine surgery patients (48 lumbar diskectomy, 60 cervical decompression and fusion, and 42 lumbar decompression and fusion [LDF]) was assembled. Patients were interviewed before surgery using a questionnaire designed in accordance with the World Health Organization and DSM-IV-TR criteria for the diagnosis of OD. The prevalence of OD was calculated based on questionnaire results. Pain intensity was quantified during admission using a 0-to-10 pain scale. We used pain intensity multiplied by duration of pain in months (WR index) as a new parameter. Lengths of stay were collected following patients' discharge from hospital. Pearson correlation and regression analysis were performed using SPSS software.

RESULTS

Thirty (20.00 percent) patients were opioid dependent. The prevalence was highest among LDF patients (23.81 percent), females (22.78 percent), and, to a lesser degree, Caucasians (20.87 percent). There was no correlation between OD and age (r = 0.08, p > 0.1) or between OD and LOS (r = 0.09, p > 0.1). This study proved a very significant positive correlation between OD and pain intensity (r = 0.24, p < 0.01) and between OD and the WR index (r = 0.30, p < 0.01). On the other hand, there was a significant positive correlation between LOS and age (r = 0.42, p < 0.01), between LOS and the number of previous spine surgeries (r = 0.28, p < 0.01), and between LOS and duration of pain (r = 0.18, p < 0.05). Regression analysis showed that age, ethnicity, and type of surgery were the main determinants of LOS.

CONCLUSIONS

Chronic pain and prolonged use of opioids raise the prevalence of OD in spine surgery patients to 20 percent. The lack of effect of OD on LOS after surgical intervention means that efforts to decrease LOS by trying to satisfy patients' craving for opioids will not be fruitful. Older, African-American LDF patients with a lengthy history of pain and multiple spine surgeries in the past are the most likely to stay longer in hospital.