Pain Reports 2025 (Dec 12); 11 (1): e1374

Table 3.

GRADE evidence profile for the impact of chiropractic care on initiation of prescription opioids and other patient-important outcomes for noncancer spine pain.

Study characteristics	Quality assessment					Summary of findings			Overall certainty of evidence
No. of studies (participants)	Risk of bias	Inconsistency	Indirectness	Imprecision	Publication bias	Treatment association (95% CI)	Absolute risk
No. of studies (participants)	Risk of bias	Inconsistency	Indirectness	Imprecision	Publication bias	Treatment association (95% CI)	Baseline risk	Risk difference (95% CI)
*Impact of chiropractic care on prescription opioid receipt^ (yes vs no)**
2 RCTs (838)	Serious risk of bias^†	Serious inconsistency (I² = 98%)^‡	Serious indirectness^§	No serious imprecision	NA (only 2 studies)	OR 0.66 (0.50–0.86)	65/100^‖	10 fewer per 100 (−4 to −17)	Very low
Early DC care: 14 cohort studies^¶ (3,487,063)	Serious risk of bias^#	No serious inconsistency (τ² = 0.65)^**	No serious indirectness	No serious imprecision	Undetected; Egger test, P = 0.85	OR 0.33 (0.22–0.51)	24/100^‖	15 fewer per 100 (−10 to −18)	Very low^††
Later DC care: 5 cohort studies^‡‡ (77,548)	Serious risk of bias^#	No serious inconsistency (τ² = 0.09)	No serious indirectness	No serious imprecision	NA (only 5 studies)	OR 0.73 (0.53–0.99)	51/100^‖	8 fewer per 100 (−0.3 to −15)	Very low
Impact of chiropractic care on long-term opioid use^§§ (yes vs no)
6 cohort studies (2,597,028)	Serious risk of bias^#	No serious inconsistency (τ² = 0.45)^**	No serious indirectness	No serious imprecision	NA (only 6 studies)	OR 0.27 (0.15–0.47)	4/100^‖	3 fewer per 100 (−2 to −3.4)	Very low^††
Impact of chiropractic care on pain intensity (10-cm VAS for pain; lower is better; MID = 1.5 cm)
2 RCTs (838)	Serious risk of bias^†	No serious inconsistency (I² = 56%)	No serious indirectness	No serious imprecision	NA (only 2 studies)	WMD –0.64 (−1.01 to −0.28)	20/100^‖‖	8 more per 100 (3–14)	Moderate
Impact of chiropractic care on physical functioning (0–24 point RMDQ scale; lower is better; MID = 3 points)
2 RCTs (838)	Serious risk of bias^†	No serious inconsistency (I² = 0%)	No serious indirectness	No serious imprecision	NA (only 2 studies)	WMD –2.03 (−3.15 to −0.91)	36/100^‖‖	9 more per 100 (3–15)	Moderate
Impact of chiropractic care on nonserious adverse events (yes vs no)^¶¶
2 RCTs (838)	Serious risk of bias^†	No serious inconsistency (I² = 0%)	Serious indirectness^##	No serious imprecision	NA (only 2 studies)	RR 1.97 (1.17–3.34)	5/100^‖	5 more per 100 (1–8)	Low
Impact of chiropractic care on serious opioid-related adverse drug events (yes vs no)
1 cohort study (744,942)	Serious risk of bias^#	NA (only 1 study)	No serious indirectness	No serious imprecision	NA (only 1 study)	RR 0.29 (0.25–0.32)	0.3/100	0.2 fewer per 100 (−0.2 to −0.2)	Very low^††

^* We found a significant subgroup effect in 14 cohort studies.^{6,10,26,40,42,47,52,73,78a-c,79} between early vs later receipt of chiropractic care (moderate credibility; interaction, P < 0.001).
^† Outcomes were subjective (ie, patient-reported) and may have been influenced by the lack of blinding of patients and healthcare providers.
^‡ One study suggests a moderate reduction in the risk of initiating opioids with chiropractic care, and 1 study suggests that no patient receiving chiropractic care will be prescribed opioids.
^§ We rated down for indirectness because the authors in 1 trial³⁴ did not stratify by opioid-naive vs opioid-using or opioid vs nonopioid analgesics (including over-the-counter) in their results.
^‖ Based on the median control group risk across studies. The mean control group risk was used when there were only 2 studies.

^¶ Association in 14 cohort studies between prescription opioid receipt and “early” chiropractic exposure, defined as receipt of chiropractic services within the first 30 d after an index visit for an acute or chronic noncancer spine pain diagnosis.
^# Most included cohort studies (94%) were at high risk of bias due to insufficient control of confounding. We did not rate down an additional level for risk of bias because our subgroup analyses found no credible subgroup effects between the pooled estimate and other risk-of-bias components.
^** We did not rate down for inconsistency because all studies suggest benefit with chiropractic care, and uncertainty appears to be the magnitude of association rather than whether there is an association.
^†† The measure of association showed large effects, but we elected not to rate up our certainty in the evidence as the studies contributing to the pooled estimate were at high risk of bias.
^‡‡ Association in 5 cohort studies between prescription opioid receipt and “later” chiropractic exposure, defined as receipt of chiropractic services >30 d after an index visit for an acute or chronic noncancer spine pain diagnosis.
^§§ Defined as receiving at least 5 opioid prescriptions, or the equivalent of 144 days' supply of opioids, over a 12-month period.
^‖‖ Based on the mean control group probability of achieving at or above the MID across studies.
^¶¶ Adverse events attributed to chiropractic care in 1 trial³⁴ included muscle soreness or stiffness (n = 37), or transient paresthesia (n = 1). Adverse events reported for usual medical care were related to prescribed medications (n = 3), epidural injections (n = 4), or muscle or joint stiffness (n = 12) attributed to physical therapy or self-care recommendations.³⁴
The second trial¹¹ reported that there were no adverse events to chiropractic treatment.
^##
We rated down for indirectness because the authors in 1 trial¹¹ did not report adverse events for the control group.
CI, confidence interval;
DC, doctor of chiropractic;
GRADE, grading of recommendations assessment, development, and evaluation;
MID, minimally important difference;
NA, not applicable;
OR, odds ratio;
RCT, randomized controlled trial;
RMDQ, Roland-Morris Disability Questionnaire;
RR, relative risk;
VAS, visual analogue scale;
WMD, weighted mean difference.