Are perioperative therapeutic doses of statins associated with postoperative pain and opioid consumption after hip surgery under spinal anaesthesia?

Background. The anti-inflammatory effects of statins have been suggested to relieve postoperative pain. This retrospective study tested the association between the perioperative routine use of statins in therapeutic doses, and opioid requirements and pain scores, after hip replacement surgery. Methods. With IRB approval, data was obtained for adult patients who had elective hip replacement surgery under spinal anaesthesia at Cleveland Clinic between 2005 and 2015. Patients were compared using a joint hypothesis framework. We used the inverse probability of treatment weighting method to control for observed confounding factors (a total of 26). Results. We included 611 statin users and 780 non-statin users. Pain score during the initial 72h after surgery was 0.07 higher (95% CI:-0.02, 0.17) in statin users (noninferiority test in both directions P<0.001). The estimated ratio of geometric means in the cumulative i.v. morphine equivalent opioid consumption was 1.01 (95% CI: 0.93, 1.10) for statin vs non-statin users (noninferiority test P=0.001 in the hypothesized direction and<0.001 in the other direction) during the initial 72h after surgery. The statin and non-statin patients were deemed equivalent on postoperative opioid consumption and pain score. Conclusions. This is the first large retrospective clinical study that investigates the effects of statin use on postoperative pain and opioid consumption. We observed no difference between statin users and non-users during the initial 72h after hip surgery. Our findings do not support the routine use of statins as part of an analgesic regimen.