Sex differences in characteristics of smokers with chronic pain undergoing multidisciplinary pain rehabilitation

Objective. The primary aim of this study was to determine the influence of sex and the interactions between sex and smoking status on the immediate treatment outcomes of patients undergoing multidisciplinary pain treatment. Design. A retrospective, repeated measures design. Setting. Multidisciplinary pain rehabilitation center at a tertiary referral medical center. Patients. The cohort (N = 1,241) included 928 women and 313 men of whom 313 were current smokers, 294 were former smokers and 634 were never smokers consecutively admitted from September 2003 through February 2007. Interventions. A 3-week outpatient multidisciplinary pain rehabilitation program. Outcome Measures. The Multidimensional Pain Inventory, Short Form-36 Health Status Questionnaire, Center for Epidemiologic Studies-Depression scale, Pain Anxiety Symptom Scale, and Pain Catastrophizing Scale were administered at admission and dismissal. Results. Women experienced significantly greater improvement in depressive symptoms compared with men (P = 0.023). Smokers experienced significantly greater improvements in depression (P = 0.039), pain catastrophizing (P = 0.010), and anxiety (P = 0.037) compared with former and never smokers. No significant interaction effects between treatment by sex by smoking status were observed. A significant sex by smoking status interaction was observed for daily morphine equivalent dose (mg/d) where male smokers consumed greater quantities of opioids compared with female smokers at program admission (P < 0.001). Conclusions. The effects of smoking status on the immediate treatment outcomes of multidisciplinary pain treatment are not modified by sex. However, women experienced significantly greater improvement in depression than men and male smokers consumed significantly greater quantities of opioids compared with female smokers at admission.