The study’s three primary outcomes of hip pain severity 2 weeks after the injection on a 0-10 scale at rest and during walking and on the WOMAC pain subscale revealed inconsistent results with the treatment.
At the 2-week follow-up, patients who had received the IM glucocorticoid injection had a significant and clinically relevant difference in hip pain at rest (between-group difference = –1.3; 95% confidence interval, –2.3 to –0.3; P = .01). But at this time point there were no significant associations between glucocorticoid injection and hip pain during walking (difference = –0.9; 95% CI, –1.9 to 0.1; P = .07) and WOMAC pain subscale score (difference = –6.1; 95% CI, –13.4 to 1.2; P = .10), the researchers reported.
At 2-week follow-up, recipients of the glucocorticoid injection were significantly more likely to perceive improvement (relative risk = 1.7; 95% CI, 1.1 to 2.7; P = .02) or achieve OMERACT-OARSI level of response (RR = 2.0; 95% CI, 1.1 to 3.6; P = .03).
The authors described this finding as “surprising,” speculating that the 7-point Likert scale used to measure perceived improvement could have resulted in less power.