Human umbilical cord blood-derived mesenchymal stem cell therapy in experimental spinal cord injury: A systematic review and meta-analysis

Table 2 GRADE evidence profile for human umbilical cord blood-derived mesenchymal stem cells therapy in experimental spinal cord injury

Outcome (population)	Study IDs (number of animals)	Effect estimate (95%CI)	I2	Certainty (GRADE)	Key limitations (reasons for downgrading)
Functional recovery
Rat (BBB scale)	R1, R3, R5 (102)	SMD 2.32 (-2.14 to 6.78)	91.4%	Low	Serious inconsistency (I2 > 80%), serious imprecision (wide CI crossing zero)
Canine	R2, R4 (16)	SMD 1.75 (1.21-2.28)	0%	Very low	Very serious imprecision (very small sample size, n = 16); serious risk of bias
Rabbit (Reuter)	R6 (14)	SMD 3.79 (2.04-5.54)	N/A	Very low	Very serious imprecision (very small sample size, n = 14); serious indirectness (scale transformation)
Safety
Mortality (all species)	R1, R2, R3, R4, R5, R6 (172)	RR 1.20 (0.60-2.40)	30%	Very low	Very serious imprecision (CI includes both appreciable harm and no difference), serious risk of bias (inadequate AE reporting)

Note: (1) For the Reuter score (originally lower-is-better), means were multiplied by -1 prior to analysis so that a positive standardized mean difference indicates a treatment benefit; (2) The “serious imprecision” rating reflects wide confidence intervals or small sample size, indicating uncertainty about the precise magnitude of the treatment effect; and (3) The “low” overall rating for functional recovery reflects serious inconsistency (I² = 81.8%) and serious imprecision. Risk of bias was not further downgraded because unclear judgments primarily reflected poor reporting rather than confirmed high risk. BBB: Basso, Beattie, and Bresnahan; CI: Confidence interval; SMD: Standardized mean difference; RR: Risk ratio; N/A: Not applicable; AE: Adverse event.