Lack of Efficacy of Acetaminophen in Treating Symptomatic Knee Osteoarthritis
Bibliographic record
Abstract
BACKGROUND: Recommendations state that acetaminophen should be used in preference to nonsteroidal anti-inflammatory drugs in the initial treatment of symptomatic osteoarthritis (OA) of the hip or knee, because of lesser toxicity and the pervasive belief that acetaminophen is not only effective in treating OA pain but is of equal analgesic efficacy as nonsteroidal anti-inflammatory drugs. METHODS: This was a randomized, double-blind, placebo-controlled trial of diclofenac sodium, 75 mg twice daily, vs acetaminophen, 1000 mg 4 times daily, in 82 subjects with symptomatic OA of the medial knee. Osteoarthritis was quantitated radiographically, and subjects met stringent baseline pain criteria. The primary evaluation of efficacy used the Western Ontario and McMaster Universities Osteoarthritis Index, with evaluations at screening, baseline, and 2 and 12 weeks after treatment. Intention-to-treat analysis was used. RESULTS: Twenty-five subjects were randomized to diclofenac, 29 to acetaminophen, and 28 to placebo. The groups were closely matched for age, sex, body mass index, prior use of OA medications, baseline pain, and radiographic features. At 2 and 12 weeks, clinically and statistically significant (P<.001) improvements were seen in the diclofenac-treated group; however, no significant improvements were seen in the acetaminophen-treated group (P =.92 at 2 weeks and.19 at 12 weeks). Stratification of subjects according to baseline pain, prestudy OA medication, and radiographic grade showed no clear pattern of preferential response to diclofenac, and did not reveal a subset of subjects who responded to acetaminophen. CONCLUSIONS: Diclofenac is effective in the symptomatic treatment of OA of the knee, but acetaminophen is not. A review of the literature reveals that there is scanty published evidence for a therapeutic effect of acetaminophen relative to placebo in patients with OA of the knee, because most published studies use active comparators (ie, nonsteroidal anti-inflammatory drugs) only. The advocacy of acetaminophen use in subjects with OA of the knee should be reconsidered pending further placebo-controlled studies.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".