Age, sex, race and ethnicity representativeness of randomised controlled trials in peri-operative medicine

The applicability of the results of any clinical trial will depend to a large extent on whether the study population is representative of the population seen in clinical practice. The growing older surgical population presents challenges for peri-operative researchers to ensure there is adequate representation of patients in terms of their age, sex, race and ethnicity in clinical trials. A review of purposively sampled published randomised controlled trials was performed to establish the age, sex, race and ethnicity of study participants. These data were compared with national registry data for the relevant surgical populations. We included 224 peri-operative trials that were cited in 469 retrieved meta-analyses. Of these, 50 (22.3%) had an upper age limit to recruitment. The median (range [IQR]) difference in study population age from the registry population age was: -2.4 (-6.2 to 1.0 [-34.7 to 14.5]) years for all randomised controlled trials; -6.2 (-9.4 to -2.8 [-18.6 to 4.6]) years for randomised controlled trials of patients undergoing hip arthroplasty; and -3.4 (-9.6 to -1.1 [-34.7 to 2.9]) years for randomised controlled trials of patients undergoing hip fracture surgery. In 92 (41.1%) randomised controlled trials, the proportion of each sex in the study population was more than 25% different from the proportion in the registry population. Only 5 (2.2%) trials published data on the race or ethnicity of participants. We conclude that peri-operative randomised controlled trials are unlikely to be representative of the age and sex of clinically treated surgical populations. Researchers must endeavour to ensure representative study populations are recruited to future clinical trials.