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 .
Responsiveness of efficacy endpoints in clinical trials with over the counter analgesics for headache
Aim : To quantify and compare the responsiveness within the meaning of clinical relevance of efficacy endpoints in a clinical trial with over the counter ( OTC ) analgesics for headache . Efficacy endpoints and observed differences in clinical trials need to be clinical ly meaningful and mirror the change in the clinical status of a patient . This must be demonstrated for the specific disease indication and the particular patient population based on the application of treatments with proven efficacy . Methods : Patient ’s global efficacy assessment during two study phases ( pre-phase and treatment phase ) was used to classify patients as satisfied or non-satisfied with the efficacy of their medication . The analysis is based on 1734 patients included in the efficacy analysis of a r and omized , placebo-controlled , double-blind , multi-centre parallel group trial with six treatment arms . Based on this classification and the pain intensity recorded by the patients on a 100 mm visual analogue scale , group differences by assessment categories and receiver operating characteristic ( ROC ) curve methods were used to quantify responsiveness of the efficacy endpoints ‘ time to 50 % pain relief ’ , ‘ time until reduction of pain intensity to 10 mm ’ , ‘ weighted sum of pain intensity difference ’ ( % SPIDweighted ) , ‘ pain intensity difference ( PID ) relative to baseline at 2 hours ’ , and ‘ pain-free at 2 hours ’ . Results : Clinical ly relevant differences between patients satisfied and non-satisfied with the treatment were observed for all efficacy endpoints . Patients with the highest rating of efficacy had the fastest and strongest pain relief . In comparison , patients assessing efficacy as ‘ less good ’ reached a 50 % pain relief on average nearly an hour later than those scoring efficacy as at least ‘ good ’ . Simultaneously , their extent of pain relief was only half as great 2 hours after medication intake . Patients scoring efficacy as ‘ poor ’ experienced practically no pain relief within the 4 hour observation interval . ROC curve calculations confirmed an adequate responsiveness for all continuous endpoints . The following cut-off points for differentiating between satisfied and non-satisfied patients were deduced from the data in the pre- and treatment phase , respectively : ‘ time to 50 % pain relief ’ 1:10 and 1:31 h : min , ‘ time until reduction of pain intensity to 10 mm ’ 2:40 and 3:00 h : min , ‘ % SPIDweighted ’ 68 and 64 % , ‘ PID at 2 hours ’ 35 and 35 mm . The sensitivity and specificity based on these cut-off points ranged from 70 to 79 % . The binary endpoint ‘ pain-free at 2 hours ’ showed a clearly higher specificity ( 80 and 87 % ) than sensitivity ( 65 and 61 % ) in the pre- and treatment phase , respectively . Conclusions : When global assessment of efficacy by the patient was used as external criterion , ROC curve calculations confirmed a high responsiveness for all efficacy endpoints included in this study . Clinical ly relevant differences between patients satisfied and non-satisfied with the treatment were observed . The endpoint ‘ % SPIDweighted ’ proved slightly but consistently superior to the other endpoints . SPID and % SPIDweighted are not easy to interpret and the time course of pain reduction is of high importance for the patients in the treatment of acute pain , including headache . The endpoint ‘ pain-free at 2 hours ’ showed the expected high specificity , but at the cost of a concurrently low sensitivity and clearly makes less use of the available information than the endpoint ‘ time to 50 % pain reduction ’ , which combines the highly relevant aspects of time course and extent of pain reduction . Responsiveness , the ability of an outcome measure to detect clinical ly important changes in a specific condition of a patient , should be added in future revisions of IHS guidelines for clinical trials in headache disorders
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 .