Gender Differences in Preoperative Opioid Use in Spine Surgery Patients: A Systematic Review and Meta-analysis.

OBJECTIVE Opioids are frequently used in spine surgeries despite their adverse effects, including physical dependence and addiction. Gender difference is an important consideration for personalized treatment. There is no review assessing the prevalence of opioid use between men and women before spine surgeries. DESIGN We compared the prevalence of preoperative opioid use between men and women. SETTING Spine surgery. SUBJECTS Comparison between men and women. METHODS PubMed, Embase, and Cochrane were searched from inception to November 9, 2018. Clinical characteristics and prevalence of preoperative opioid use were collected. Where feasible, data were pooled from nonoverlapping studies using random-effects models. RESULTS Four studies with nonoverlapping populations were included in the meta-analysis (one prospective, three retrospective cohorts). The prevalence of preoperative opioid use was 0.64 (95% CI = 0.40-0.83). Comparing men with women, no statistically significant difference in preoperative opioid use was detected (relative risk [RR] = 0.99, 95% CI = 0.96-1.02). Surgery location (cervical, lumbar) and study duration (more than five years or five years or less) did not modify this association. All involved open spine surgery. Only one secondary analysis provided data on both pre- and postoperative opioid use stratified by gender, which showed a borderline significantly higher prevalence of postoperative use in women than men. CONCLUSIONS The prevalence of opioid use before spine surgery was similar between men and women, irrespective of surgery location or study duration. More studies characterizing the pattern of opioid use between genders are still needed.