Table 1.
Compatibilities and limitations for including studies in the meta-analysis
| Clinical comparison and trials | Compatibilities | Limitations |
|---|---|---|
| Antivenom vs. placebo (old world scorpions) | ||
| Abroug et al. [15] and Belghith et al. [16] | Both trials are from the same geographical region | Other treatment had been prescribed at clinicians discretion |
| Both trials conducted in the same time frame | Findings are only applicable to the mentioned scorpion species and the particular antivenom tested | |
| The antivenom was produced against the same scorpion species: A. australis and B. occitanus | Both trials had been published over 15 years ago | |
| Dosage of antivenom was similar and was capable of neutralizing more than 10LD50 of venom/ml | ||
| Both trials were randomized prospective clinical trials | ||
| Severity grading of scorpion stings was similar | ||
| Antivenom vs. placebo (new world scorpions) | ||
| Two trials by Boyer et al. [19, 20] and one trial by LoVecchio et al. [18] | All three trials conducted in close geographical range (Arizona, USA and Mexico) | Severity grading on admission done by LoVecchio et al. only. Both other studies report venom concentration on admission by assays and give a descriptive analysis of symptoms |
| All three trials used antivenom against Centruroides sp. | The neutralizing capacity of (LD50 equivalent in mice) administered antivenom reported in one trial only (Boyer et al. 2013) | |
| Symptom resolution at 4 h is reported in two trials and can be inferred by reported data in the third trial (LoVeccio et al.) | The differences in study design of the included studies are explained in Table 1 | |
| All trials were on children or young adults (2 trials enrolled within an age range of 6 months to 18 years while the third included children under 2 years) | Trial findings and recommendations are limited to Centruroides sp. In Central America and Southern States of USA | |
| Antivenom and prazosin vs. prazosin alone | ||
| Bawaskar et al. [23], Natu et al. [22] and Pandi et al. [24] | All trials have been conducted in India | Heterogeneity in age groups (however, antivenom dosage was not dependent on age) |
| All trials included antivenom against M. tamulus | Other differences in study design are explained in Table 2 | |
| All trials report the mean time to resolution of symptoms | Two trials used the same protocol for antivenom administration and severity grading while the third (Natu et al.) used a different protocol | |
| All trials have used the same monovalent antivenom from the same company | Interpretations and recommendations limited to M. tumulus in India | |
| The maximum amount of venom injected per sting by M. tamulus is 1.5 mg and each ml of antivenom neutralized 1.2–1.5 mg of venom. All trials used at least 30 ml of venom per patient irrespective of the age | ||