Background: Financial conflict of interest has been associated with
an increased likelihood that authors will report positive study outcomes. The
purpose of this study was to investigate the association between types of
declared conflict of interest and reported study outcomes in orthopaedic
research.
Methods: The abstracts of all podium presentations given at the 2001
and 2002 Annual Meetings of the American Academy of Orthopaedic Surgeons were
analyzed by three orthopaedic surgeons with advanced training in clinical
epidemiology. The findings reported in each abstract were graded as positive,
negative, neutral, or not applicable. Self-reported conflict of interest was
recorded and classified.
Results: Conflicts of interest were reported in 40.8% (212) of 519
abstracts. The interobserver reliability of the grading of the study findings
was acceptable (intraclass correlation coefficient, 0.725). Rates of conflict
of interest related to royalties, stock options, or consultant or employee
status varied significantly by subspecialty field (p < 0.001). The overall
rate of positive study findings was 84.0% (436 of the 519 abstracts). Positive
findings were more common in studies authored by individuals with a conflict
of interest related to royalties (98.4% [sixty of sixty-one] compared with
88.0% [381 of 433] for studies authored by individuals without a conflict of
interest related to royalties; relative risk = 1.1 [95% confidence interval =
1.0 to 1.1]; p = 0.02), in studies authored by individuals with a conflict of
interest related to stock options (100.0% [twenty-nine of twenty-nine]
compared with 84.7% [394 of 465]; relative risk = 1.2 [95% confidence interval
= 1.0 to 1.3]; p = 0.04), and in studies authored by individuals with a
conflict of interest related to consultant or employee status (97.8%
[ninety-one of ninety-three] compared with 89.0% [357 of 401]; relative risk =
1.1 [95% confidence interval = 1.0 to 1.2]; p = 0.01). Positive findings were
not more common in studies authored by individuals with a conflict of interest
related to research or institutional funding (93.5% [143 of 153] compared with
91.8% [313 of 341]; relative risk = 1.0 [95% confidence interval = 0.95 to
1.5]; p = 0.65). In the multivariate analysis, the factors that remained
significant predictors of positive outcomes were royalties (p = 0.002) and
consultant or employee status (p = 0.038).
Conclusions: Self-reported conflicts of interest are common in
orthopaedic research, particularly in the subspecialty fields of adult
reconstruction of the knee, adult reconstruction of the hip, and spine.
Presentations authored by individuals with a conflict of interest related to
royalties, stock options, or consulting or employee status were significantly
more likely to describe positive findings. While there may be distinct
benefits associated with industry support of orthopaedic research, safeguards
must be established to maintain public trust in the medical research
establishment.