From analyses of individual patient data ( seven studies , 918 patients ) , we found baseline pain strongly associated with absolute , but not relative , MCID as patients with higher baseline pain needed larger pain reduction to perceive relief .
Conclusions The MCID in acute pain varied greatly between studies and was influenced by baseline pain , definitions of improved patients and study design .
Background The minimum clinical ly important difference ( MCID ) is used to interpret the clinical relevance of results reported by trials and meta-analyses as well as to plan sample sizes in new studies .
However , there is a lack of consensus about the size of MCID in acute pain , which is a core symptom affecting patients across many clinical conditions .
Intravenous acetaminophen for pain after major orthopedic surgery: an expanded analysis.
BACKGROUND AND METHODS From the time that Sinatra et al. ( Anesthesiology . 2005;102:822 ) was published to FDA apaproval of intravenous ( IV ) acetaminophen , an exp and ed analysis of the original raw study data became necessary for the regulatory su bmi ssion . The following analyses were conducted : ( 1 ) sum of pain intensity differences over 24 hours ( SPID24 ) using currently accepted imputation methods to account for both missing data and the effects of rescue ; ( 2 ) efficacy results after the first 6 hours ; ( 3 ) effects of gender , race/ethnicity , age , weight , surgical site , ASA Class , and serotonin antagonists ; and ( 4 ) a stepwise regression analysis of why adverse events of nausea and vomiting were numerically ( although not statistically ) higher in the IV acetaminophen group compared with placebo . RESULTS Sum of pain intensity differences over 24 hours using a 0- to 100-mm visual analog scale was statistically significantly ( P < 0.001 ) in favor of IV acetaminophen  ( n = 49 ) compared with placebo ( n = 52 ) . Time to rescue was found to be 3.9 and 2.1 hours , respectively , for total hip and knee arthroplasty compared with 0.8 hours for the placebo group . Rescue medication consumption , requests , and actual administration were all significantly lower in the IV acetaminophen group compared with placebo for each dosing interval , except in the 6- to 12-hours interval where a numerical trend was observed . Analysis of various subset variables demonstrated similar efficacy for each variable . A stepwise regression analysis demonstrated that AE reports of nausea and vomiting were most likely due to prer and omization events , particularly opioid consumption and presence of nausea prior to r and omization . CONCLUSION Repeated-dose 24-hours end points were found to be as robust as previously published results . IV acetaminophen  efficacy and safety appeared to be unaffected by specific subset variables .
From analyses of individual patient data ( seven studies , 918 patients ) , we found baseline pain strongly associated with absolute , but not relative , MCID as patients with higher baseline pain needed larger pain reduction to perceive relief .
Conclusions The MCID in acute pain varied greatly between studies and was influenced by baseline pain , definitions of improved patients and study design .
Background The minimum clinical ly important difference ( MCID ) is used to interpret the clinical relevance of results reported by trials and meta-analyses as well as to plan sample sizes in new studies .
However , there is a lack of consensus about the size of MCID in acute pain , which is a core symptom affecting patients across many clinical conditions .