Most trials subject to mandatory reporting do not report within a year

An article in BMJ explores how well registered trials adhere to reporting deadlines.

They found, overall, very low compliance.  Interestingly, industry-funded trials were significantly more likely to report results than other trials:

Of the 738 trials that were classified as subject to mandatory reporting, 163 (22%) had reported results. In comparison, 76/727 (10%) trials covered by the FDAAA but not subject to mandatory reporting had reported results (95% confidence interval for the difference in proportions 7.8% to 15.5%; χ2test, P=2.6×10−9).

The proportion of trials subject to mandatory reporting that had reported results was influenced by the phase of the study (table 1⇓). Fewer phase II trials had reported results compared with phase III and IV trials (χ2test, P=4.4×10−11). We categorised the funder of the trial as industry, mixed, National Institutes of Health/government, or other and found that the funder of the trial influenced the proportion that had reported results (Fisher’s exact test, P=2.2×10−16) (table 2⇓). Industry funded trials were more likely to report results. We therefore grouped trials subject to mandatory reporting into “solely industry funded” and “not solely industry funded.” More solely industry funded studies (126/317; 40%) had reported results than had those not solely industry funded (37/421 (9%); 95% confidence interval for the difference 24.7% to 37.3%; χ2test, P=2.2×10−16).