Are adequate PROMs used as outcomes in randomized controlled trials? an analysis of 54 trials.

Results by patient-reported outcome measures (PROMs) from randomized controlled trials (RCTs) in musculoskeletal research often influence healthcare strategies. We aimed to evaluate to which extent these RCTs use adequate PROMs, and how this influences the results and conclusions. We identified RCTs of sports research relevance with PROMs as primary outcomes published in 13 preselected journals between January 1, 2008, and November 1, 2019; all journals regularly publish results from musculoskeletal research. Five journals have a high impact factor (>15), and eight with lower impact factors are widely read journals. It was assessed whether the RCTs had used PROMs with high content validity and whether the most adequate PROMs were used (ie, the most well developed and well validated for the patients enrolled in the study). We registered journal impact factor, year of publication, existence of a registered protocol, and whether the study showed significant difference between interventions. A total of 54 RCTs with 56 primary outcomes comprising 26 different PROMs were identified. For 13 RCTs (24%), a protocol was not published. In only 24 of RCTs (44%), the most appropriate PROM had been used as primary outcome, independent of a registered protocol, ranking of the journal, and year of publication. In seven cases, PROMs were used to evaluate a condition that they had not been developed for. RCTs that used the most adequate PROM showed significantly more often (46%) difference in outcomes in contrast to RCTs that used inadequate PROMs (22%) (P = 0.0483). In conclusion, in the majority of RCTs, the most adequate PROM had not been used. Studies, in which the most adequate PROM had been used as outcome, were significantly more likely to show significant difference between interventions. The extent to which protocols were not available was surprisingly high. Journals should request that adequate PROMs are used in RCTs, and if this is not the case that it is discussed how it might influence the results and conclusions. Likewise, it should be requested that a protocol is published or registered.