Randomised controlled trial of rhinothermy for treatment of the common cold: a feasibility study

van de Hei, Susanne; McKinstry, Steven; Bardsley, George; Weatherall, Mark; Beasley, Richard; Fingleton, James

In total 27 participants reported feeling "a lot better" within 10 days of randomisation; 17/20 310 participants from the rhinothermy group and all 10 control group participants. Two participants 311 did not fill in the modified Jackson score on the day they felt "a lot better". Therefore, an 312 estimate of the MCID used the scores of 25 participants, 16 in the rhinothermy group and nine 313 in the control group. We recognised post-hoc that the threshold "a lot better" corresponded to an 314 estimate of substantial clinical benefit rather than the MCID [31,32] and so have estimated the 315 change which represents substantial clinical benefit. The change from baseline modified 316 Jackson score which had the best sensitivity and specificity for the participants stating that they 317 felt a lot better was between 5 and 6 units on the modified Jackson Score on days 4 and 5 318 (Table 4 ). Based on this analysis, we propose that a 5 unit change in modified Jackson score is 319 the substantial clinical benefit threshold for this instrument. 320 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 The difference in modified Jackson score between the rhinothermy group and the control group 327 was greater than the substantial clinical benefit threshold on days three, four, and five, p<0.001 328 (Table 3) . 329