Warm-Needling Acupuncture Plus Tuina for Knee Osteoarthritis: Considerations Regarding Effect Estimates, Comparator Design, and Assay Standardization [Letter]

We read with great interest the recent systematic review and meta-analysis by Dong et al, which evaluated the effects of warm-needling acupuncture (WNA) combined with Tuina on inflammatory and cartilage biomarkers in patients with knee osteoarthritis (KOA). 1 The authors are to be commended for redirecting the evaluative focus away from subjective patient-reported outcome measures-such as visual analog scale (VAS) or Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores-toward objective circulating and synovial biochemical markers.Synthesizing data on critical pro-inflammatory cascades alongside a pivotal cartilage matrix degradation enzyme (MMP-3) offers valuable translational insights into non-pharmacological pain management.Nevertheless, several methodological, statistical, and laboratory considerations warrant further scrutiny, as they directly bear on the validity and interpretation of these findings.First, plausibility of large effect sizes and unstandardized biospecimen sampling.The extraordinary magnitude of the pooled standardized mean differences (SMDs) raises pressing questions regarding biological plausibility and potential effect-size inflation.The authors reported massive pooled reductions across serum CRP (SMD = -2.58),IL-6 (SMD = -2.19),IL-17 (SMD = -2.06),IL-1/IL-1β (SMD = -1.73),TNF-α (SMD = -1.63),and MMP-3 (SMD = -2.77).In clinical trials of chronic musculoskeletal pain, SMDs exceeding 1.5 to 2.0 standard deviations are exceedingly rare, even under intensive targeted biological therapies.As the authors transparently acknowledged, these findings were accompanied by extreme statistical heterogeneity (I 2 ranging from 93.7% to 97.1%) and low to very low GRADE certainty ratings. 1 However, the review did not report the distribution of study-level SMDs, individual study weighting contributions, or sensitivity analyses omitting statistical outliers.Furthermore, the lack of standardized pre-analytical reporting may account for much of this unexplained heterogeneity.Circulating and local inflammatory cytokines are exquisitely sensitive to pre-analytical handling, storage conditions, and circadian rhythms.The review did not specify whether laboratory assessors were blinded, whether the timing of biospecimen collection relative to the final treatment session was standardized, whether fasting status was controlled, or whether identical assay platforms were utilized.Notably, vigorous manual Tuina can induce transient mechanical soft-tissue stress and an acute-phase inflammatory surge; absent standardized collection windows, posttreatment biomarker concentrations may be substantially confounded by procedural timing.We suggest that the authors provide study-level effect distributions, perform outlier-restricted sensitivity analyses, and detail these laboratory parameters across the primary studies to better contextualize the biochemical findings.Second, Methodological Implications of Using Endpoint Concentrations Rather Than Baseline-Adjusted Change Scores.The analytical decision to synthesize post-treatment endpoint concentrations rather than change-from-baseline